Sennheiser IE 600

Sennheiser IE600 was a groundbreaking release for Sennheiser. They restored their position in the IEM market which Chi-Fi saturated. In 2024, do they still hold the place to challenge other IEMs with a heavy year-long discount? Let’s see

Sennheiser as an IEM Company​

Sennheiser is the most reputed audio brand in the world. But they always struggled with their IEMs. Their mid-tier IE300 was good enough for its time but struggled in the Chi-Fi-dominated market. Their flagship IE900 recently became popular among audiophiles worldwide for its technical capabilities and resolution but was neglected due to the tuning choice they followed.
They always established themselves as the pioneer of Research and Development. Two years ago they introduced the world with their latest 7mm DD-equipped masterstroke named IE600. The market flooded with praises and compliments. But do they hold up in 2024? Let’s see.

Pros​

• It is the most comfortable IEM I have ever tried
• The resolution is excellent
• Technicalities are well-implemented
• The Sub-bass is addictive
• The construction of the shell is very well done

Cons​

• MMCX Connection
• Timber could be a hit-or-miss
• Treble might be too much for some

Burn In is real​

First Audition​

A little story I must tell before starting the review. This is my second review of the IE600, first time I listened to it in 2023-Nov and disliked this IEM tonally, in almost every way. Everything with this IEM felt wrong. I thought it was my psychoacoustics but I listened to it for more than 95 hours and tested it with another reviewer too (Shabtab Quaiser). OnFacebook published a full review from my personal FB account and got backslashed a lot. I always had second thoughts since then.​

Second Audition​

In March 2024 I got to try this IEM once again and my god – it has changed. It jumped from my B- Tier to A+ tier straight. So what happened in the meantime, keeping the source, tips & wire unchanged? Burn In. I get some of you might disagree with the term like me (before the incident).​

So this is the review of Sennheiser IE600 from my perspective​

Dig a little deeper into the tuning methodologies​

IE600 is a very fun IEM to start with. It is tuned having a different tuning philosophy in mind than the Sennheiser IE900. You can watch the interview of Jermo with Doug on the YouTube channel DMS. The first time you put this IEM in your ears, everything would sound very fun, from bass to treble. So throw neutrality out of the window and spectate this IEM as if you are in for fun.


Let’s start the discussion with its timber characteristics. (It is the worst part of this IEM still I would suggest you to not judge it with its timber only).

Timber​

Violin – Sounds transient and very fast. They do miss a little bit of low-end that gives them a fuller body. The upper registers are clear as glass and vividly detailed.

Acoustic Guitar – They sound more digitized than the neutral. They hold the sub-bass in great quantity and the details are excellent but they lack the lifelike feel and you might imagine it as a Contrasting image than a natural one.

Drums – Decay and attack of drums are exceptional. They feel organic and very satisfying in general. They also do not sound very original. Although you will enjoy drums on this IEM a lot just to give it a reference, it sounds less realistic than Softears RSV. Cymbals are very airy and full of details. Trailing edges are exceptionally expressed in this IEM.

Classical Guitar – Classical guitar is not optimal for this IEM, it makes the classical guitar sound body-less and note weights are not well presented.

Cello/Bass – The bass on this IEM sounds very average too. The midrange recession is to blame here. They are full of details but they lack the natural feel too.

Wind Instruments – Wind instruments sound amazing in this IEM. Everything is full of air, full of details and the transient nature is extremely satisfying.

Getting straight to the tonality of this IEM​

Don’t trust graphs alone, without listening first.
Duggu

Click to expand...

Tuning Analysis​

Sub-bass​

The sub-bass of this IEM is extremely good. I am astonished at how they could pull out this performance from a 7mm driver. The attack is full of air, thump is real and authoritative. Attacks are full-bodied and won’t miss a spot in your ambience. In one word the subbass is addictive. I do sometimes EQ the sub-bass 2 / 2.5 db just for extra fun and even then they don’t sweat a bit.

Mid-bass​

The midbass is not as authoritative as the sub-bass but it holds a great body and the fall of the sub-bass never feels unnatural. It was there when needed, and provided the entire spectrum to have a very happy base to play.

Lower Mids ( & Male Voice)​

Lower mids are recessed but they hold the resolution in return. Of course, this is not a mid-focused IEM and you should not expect very much at this price point but even then they do not fail to provide. I am a very mid-centric listener and even then it was not bothersome to me.

Upper Mids ( & Female Vocals)​

Upper mids are very forward in a good way. Anything that occupies the range produced the instrument with excellent resolvability and forwardness. Upper mids flowed like a liquid without giving any harshness to my ears.

Treble​

The treble of this IEM is the showstopper again. Full with resolution and details. Airy as an open field. The extension is excellent for the price. Not only did it give a shining and glittering effect to sound but it held the trailing edges of instruments for decades. Everything was fluid like liquid and effortless handling of the post 10Khz range kept me in awe.

Cable Rolling​

Effect Audio Eros S Cable​

With this cable, Midbass got a boost, which made the mid-range more recessed. But the overall low-end got fuller and more authority is there. Midrange texture improved but they became somewhat pushed back a bit.

The metallic and sizzling feeling that came with this IEM somewhat vanished. It became more organic. The soundstage although got a massive ~15-20% increment.

Everything sounds so cohesive. But mid-range took a backseat tonally.


Now let’s discuss its compatibility with different genres of music.

POP​

This IEM is well suited for Western pop music. The shimmer and shine might be more than enough in some songs but the overall fun element of the genre can be felt in great proportion. This is mainly achievable because of its low-end performance.

Music 1: Loving on Me

Voices are dry and feel over-recessed. Subbass is pure fun. Midbass is very tasteful in proportion. Attack and Slam are on point that it doesn’t bleed into basshead territory. Treble is a bit much for treble-sensitive people.

Music 2: Paint the town red

Highly detailed. Upper registers are sculpted tonally to perfection in this price range. The vocals are very well done & sit perfectly on the mix. Treble is spacious and airy and won’t give you a chance to complain.

Music 3: Death of a Bachelor

Vocals are textured. The upper registers of vocals are very nicely done. Although mids sound a bit recessed. Sizzles and Shines in the whole album is inoffensive and doesn’t overpower the upper mids.

BLUES​

I find this IEM to be extremely good in this genre. The midbass and treble perfectly match the genre. Crispiness is very well provided and the transient nature is a match made in heaven.

Music 1: Do I Move You

Feels spacious enough but not extremely, balanced enough to not feel intimate or huge. I like this Spatial presentation which is a jack of all trades. The treble and resolution are excellent. The vocals lack a bit of texture but feel very natural in the mix.

Music 2: Hummingbird

Feels highly detailed. The bass is just perfect in ambience. Voices are placed beautifully in the mix. Everything in this song feels amazing with this IEM. The treble crispiness showed its ability in a great sense. Everything just snapped, from little cymbal hots to snare drums.

Music 3: Layla Acoustic Live

The same as above. Great attacks and decay, feels tactile and fast. Clean yet it is clinical or inorganic. Treble on this IEM is addictive, to say the least.

ROCK​

This genre might be a hit or miss according to your library. For my library it was average. Never felt that I was missing something but never got the full-bodied feeling that I often look for from this genre.

Music 1: Dreams

The bass is very satisfying, full and thumpy. Voices are very natural in the mix. Spatial elements are very well placed. The acoustic guitar on the left sounds a bit sizzling with a bit of metallic timbre. Again very detailed sounding.

Music 2: Hotel California

Very detailed again. The vocals are slightly recessed but fit well with the mix. Electric guitar misses the time to shine here as the timber is kind of not accurate. Too much treble and less body is there in the guitar. Cymbals are a bit spicy too.

Music 3: Comfortably Numb

Feels spacious enough to enjoy but not too much to lose intimacy. Again very detailed, the nuances are present everywhere. Drums are very well dictated in this song. Midrange texturing is well done too. The guitar solo was excellent too. Atmospheric, had a body, full of details.

HIP-HOP​

For Hip-Hop this IEM is excellent, the sub-bass in this IEM makes the genre so much more enjoyable that 70% of the time after review, I only listen to this genre. The details and resolution capabilities of this IEM greatly go hand in hand with this genre too. Vocals are a very nicely placed mix.

WESTERN ORCHESTRA​

This IEM fits this genre very nicely too. The halls feel spacious and large-sounding. The position of the instruments is very accurately done, and air frequencies are present in a great margin. The resolution of this IEM matches with the textural information in the tracks very well. Every instrument is well-defined and can be isolated from the other ones. For the discounted price of $534 in India, it is hard to find anything that competes with this regarding this genre.

Technicalities​

Soundstage​

Soundtaging on Sennheiser IE600 is a pretty tricky thing to achieve. I am glad to say that this IEM did a very good job of providing a large enough stage and not too large to feel disconnected from the emotion of the songs like the IEM Yanin Aladdin. It is round and projects instruments on the stage very precisely. It is slightly less than or on par with Aful Performer 8 depending on HRTF.

Imaging​

Imaging is very natural for its price. It does not project fake imaging nor it is very precise to a point. The localisation is good enough for the price and will feel very natural and not microscopic. Artists like Amber Rubarth are a joy to listen to on this IEM.

Resolution​

The resolution of this IEM is excellent. It eliminates IEM far beyond its discounted price point in terms of sheer resolution. It is more resolving than something like Aful Performer 8 and on par with something like Monarch MKII.

Drivability​

This IEM scales. And it requires a clean and powerful source to show its potential. It wouldn’t run properly on something like the Abigail Pro dongle. The bare minimum of this IEM is Moondrop Dawn Pro or AFUL Snowy Night. DAPs like Aune M1P matched great with this IEM and Hiby R6 Pro II matched well too.

Conclusion​

I thoroughly enjoyed this IEM even in 2024. And I can recommend this IEM left and right for its discounted price of $530. The sheer amount of fun I had with this Sennheiser IE600 is not something I am ignoring and I am optimistic about the next releases from Sennheiser’s IEM lineup. If you are a neutral listener and trying to break into the fun side of audio, I think it is a perfect entry point for that.


Ratings

Sub Bass – 7.5/10
Bass – 6/10
Lower Mid – 5/10
Upper Mid – 6.5/10
Lower Treble – 6.5/10
Upper Treble – 7.5/10
Timber – 5.5/10
Resolution – 7/10
Imaging – 6.25/10
Soundstage – 6.5/10
Overall Rating – 7.05/10

Tonality = A-

Technicality = A/A+

IE 600​

Here's the second of my reviews of my collection, the quite popular IE 600. I bought my pair at launch in early 2022, for the full MSRP of $800, as a more comfortable alternative to the IER-Z1R that I daily drove at the time. While comfort was certainly a massive improvement, there were a few significant drawbacks. Note that this review was done with the Final Audio E Type tips. While I generally try to use stock tips, that was impossible in this case. No pictures again, cause I need to take better photos.

Build & Comfort​

The actual build portion of the IE 600 is absolutely superb - it's small, comfortable, and clearly built to last. Even the proprietary MMCX was designed with durability in mind, although at massive cost to replaceability. The zirconium alloy shells, being solid, strong, and textured, feel practically indestructible. In the ~1.5 years I've owned my pair, there's not been a single scratch or blemish on them. And while the nozzle is plastic, Sennheiser's history with plastic suggests there is nothing to worry about there.

In isolation, the IE 600 is extremely comfortable being one of the smallest high-end IEMs out there. The shape also lends itself well to setting deep in your ear, without being an overly-deep insertion. The nozzle, while being a little wider than many other IEMs, also doesn't go far enough in to be an issue. The actual isolation isn't incredible though, which leads us into the most serious problem with the IE 600...

A solid 9/10. Would be 10 if the isolation was better.

The Accessories (and related issues)​

The IE 600, with little exception, comes with some of the worst accessories I've ever seen in an IEM. And not just for expensive HiFi, but in general. Seriously, ~$30 earbuds I bought from JLabs 10+ years ago had better accessories. The only thing in recent memory that was equally bad was the BL03, an IEM that goes for 1/20th what I paid for the IE 600. This has been an issue on every Sennheiser IEM I've owned, since the IE 80, and it's sad to see that they've failed miserably to rectify it after all these years.

Now, those are some awfully harsh words, but words I fully intend to back up. Let's start with the ear tips. The IE 600 comes with a nice selection of foam and silicone tips. The foams are a collaboration with Comply, while the silicones are Sennheiser's own in-house design, and both types have a thin filter attached – a nice way to keep earwax/dust out of the IEMs.

This is where the problems begin. The filter, thin as it may seem, is an essential part of the IE 600's tuning and keeps the treble from being piercing and sibilant. Meanwhile, the foam ear tips will blunt the micro details while in typical Comply fashion also degrade in the span of just a month. Never mind how you'll only have 1 pair in your size, and they're not even as comfortable as regular Comply tips.

The silicone tips however, are somehow even worse. It is almost impossible for me (and it seems most other people) to get a consistent seal with them. They're way too thin and thus when squished will collapse instead of filling your ear canal like normal silicone tips. And seeing as how human ear canals aren't perfectly cylindrical, this will consistently happen unless you're extremely careful with the insertion depth. I don’t think I ever once got them to seal perfectly in both ears and actually stay sealed.

The solution might seem obvious - 3rd party ear tips! But this is when that filter comes back to haunt us. Without it, the already spicy treble will be sibilant and piercing on many of the 3rd party tips out there. I've settled on the Final Audio E types, the best of a bunch of poor choices, but your results may vary. Do let me know if you’ve found something that works better than the E Types though, I’m always open to improvements (just not so much paying for the experimentation).

This isn't even mentioning the stock cable(s), which come in 3.5mm and 4.4mm balanced. These cables are absolutely atrocious. They're poorly behaved, prone to tangling, uncomfortable, and even worse, microphonic. The shapable (yet non-removable) ear hooks are a huge part of the problem here. It's difficult enough to shape them properly for your ears, until they change shape the moment you take the IE 600 off or wrap them for storage. The cables and ear hooks will also pull on the shells, breaking the seal on the ear tips.

But it gets even worse. The MMCX connector on the IE 600 is actually proprietary, with an extra lip that means regular MMCX connectors will be too short to make a proper connection. It might be better for durability, but this gave me hell when trying to find 3rd party replacements. It's a little better now that they've been on the market for a while, but most compatible cables will either be more expensive, or you'll need to take your chances with random AliExpress cables.

It's almost like every product Sennheiser makes has to have a proprietary cable or they won't approve it. HD600 2-pin, HD800 janky thing, IE80's weird semi-circle 2 pin, now the IE_00 line and their recessed MMCX connectors.

I find it absolutely mind boggling that Sennheiser, a huge powerhouse in the audio industry, would somehow let an $800 ($1200 if you consider that the IE 900 comes with the same accessories) product leave the lab with such terrible tips and cables. Especially when the tips and fit directly impact the sound so significantly.

The included carrying case is better, being a nice zip up hard shell. It's a little on the small side, however, and would only hold the IE 600 and your choice of USB C dongle. Anything larger and you'd run into difficulty zipping it up and possibly crush a connector. Not terrible, just not ideal.

0/10 - I'd give it a -2/10 if the case wasn't a little useful. It's like nobody even tried to use them before shipping them out.

Anyways, enough griping about the accessories, here's:

Sound Quality​

Overall, the IE 600 is a high performer, with a V-shape sound that extends well into both ends of the frequency response. While it's not my favorite type of sound, the IE 600 does what it does well really well.

Bass​

The bass digs deep into the subbass, with clear impacts and good delineation from the mid-bass and mid-range. There is no bloat or muddiness either. Overall, the IE 600 has very high-quality bass, and is relatively bassy, but keeps away from being warm or laid back. On my standard bass test track, Free Tibet (Vini Vici Remix), the IE 600 truly shows this off. At 1:40, when the bass kicks in, you can clearly feel each individual bass hit and subbass fluctuation. There’s really not much to say here, it’s just really great bass.

10/10

Mids​

The mids however are a little more recessed than I would like, even more so depending on the singer’s voice. Deeper male voices generally sound more natural, although still more pulled back than I’d like, with good rumble and gravel where expected. Brighter voices, especially brighter female vocals, however, show some issues. They tend to be a little hollow on the lower end, due to the mid-range scoop on the IE 600’s FR. On the higher end, the voices will be a little too shrill and piercing at times. Combined, this creates a sense of unevenness in the vocals – you can sometimes hear voices exhibit this as a singer moves up the frequency range.

7/10

Treble​

Finally, the treble is a little too sharp and piercing, depending on the ear tips that you’re using. This is where the horrible stock tips peek their ugly head again – without the filter in the stock tips to pull back the high end, the treble will be unpleasant and piercing especially with wide-bore tips. This combines with the pulled-back mids to make certain voices and instruments sounds hollow and flat or have an icy edge. However, this is also very tip and insertion depth dependent, so your mileage may vary. It’s not all bad though; the IE 600 extends well into the high end and sparkles where expected and prevents anything from sounding lifeless or dull. And despite being piercing at times, the treble is never quite sibilant.

7/10 to 9/10 depending on your sensitivity to treble and the tips you use.

Soundstage and Technicalities​

Perhaps a result of the emphasized treble, the IE 600 is a very detailed and well separated IEM. There’s never any sensation of blurring, muddiness, or losing track of instruments in busy sections of songs. The attack on all parts of the FR is clean and fast, with a clear delineation note to note. Microdetails as well are clear and present.

In a similar vein, the IE 600 also does a great job with instrument separation and positioning. This means that everything is clearly around you in a 3D space and can be picked out just by focusing a little on its location. And while it also manages to create layers of different pieces of the track, the IE 600 doesn’t quite manage to give them depth. Certain things will sound more forward than others, but none of it will quite sound quite distant or spacious. Especially in the central channel where things like vocals can take on an “inside your head” sensation. This is most obvious with female vocals.

The FR also doesn’t lend itself well to natural timbre, although not egregiously unnatural and strange. Instead, vocals may sound a little too grainy, hollow, or sharp depending on their range. For example, on Miwa’s ‘Hikarie – From THE FIRST TAKE’, the singer’s voice sounds almost hoarse or with a sore throat instead of a more natural texture. This holds true for most instruments and voices, although it varies for each; IE 600 is most natural with deep male vocals. This is another aspect that I feel was remedied by the filter in the stock tips. Too bad they’re absolutely unusable.

Again depends on your ear tips. Between a 6/10 and an 8/10.

Conclusion​

As you can see, I’m quite a bit more negative on the IE 600 than many other reviewers here are. However, I feel that once you factor in the atrocious accessories, the IE 600 is only left with its comfort and bass as standout qualities. And those are absolutely incredible strengths that are weighed down by so many issues (most of which are indirect results of the accessories). Perhaps if you can find the perfect 3rd party cable and tips the calculus changes, but I easily went $200 in on accessories before finding a combination that was “good enough” (Hart Audio NK + Final E Types). For my total cost (~$1k USD), there are definitely better options out there that should be considered before the IE 600.

Background and personal preferences

The headphones I love are hd600 and akg k701, esp hd600 with tubes (I use a Cavalli Tube Hybrid). I have owned an LCD 2C, though I loved it a lot I found myself using 600 more. Also had grado sr80 and 225 at some point which followed the same pattern of me moving to 600.

On the good iem side, I have had blon bl03, er2xr and xba N3. I really liked oppoty, and the isolation of etys. But in terms of pure fun, N3 was the clear winner. I am slo an owner of sr846 since last three weeks, which I really really enjoy.

Now that my preferences and experiences are out of the way, here are my impressions on ie600.


Me and ie600 :-

I will be comparing the ie600 with N3 since it has been my daily driver for so lone.

The fit is okay for me. Maybe its the shape of my ears, I don't feel very comfortable with them, they are okay though. The cable is not for me, there is cable noise and I find myself constantly bothered with it touching my neck. Tips aren't perfect for my size either but they are okay. In terms of these experiences, I find N3 much much better. SE846 is the most premium in this regard, I love the cables and fit, and all accessories. They are a more comfortable fit than ie600 for me, and with ety styled 3 flanged tip, they seal so damn good.

I should also mention that I did some tip rolling since that was suggested for reducing treble. I have tried tips from Sony N3 pack, the one from mh755, and some Brainwavz delta tips I had lying around. There wasn't much difference, atleast worth changing to. Anyway, in the end, I think that the sound signature is just not for me. It is not bad, and I would have no problem listening but when there are comparisons to be made, I will go with the rest.

My impressions on the sound (secondary parameters) -

Details are really great, on par with se846. Maybe ie600 delivers more, but it probably comes from the treble extension since se846 lacks there. I find the soundstage pretty decent, but I prefer 846 in this regard. Imaging is good and overall everything sounds crisp.

I can stay its a step up from N3 but diminishing returns, I am more than happy with N3 details and though ie600 is superior, they aren't too much of a step up to N3 in terms of these factors. In terms of 846, I don't call it an upgrade. ie600 is more like a different flavour of sound.

My impressions on the sound (primary parameter) -

By primary parameter, I mean the factor that make me keep the iem. For example, N3 replaced er2xr for me. There was a bit more detail to N3, more bass which surprisingly I loved and overall sound signature of sony which is really fun. N3 did all of this without being fatiguing.

Now, when it comes to ie600, I am not really happy with the signature. The metallic nature of sound (treble sided signature) is off putting at times, also fatiguing. Since my audiophile vocabulary is limited, I will try to explain using some songs I know well and how they sounded on ie600. To put it bluntly, I find 846 more natural and ie600 more treble heavy. In crude terms, for example, the cymbal sounds in background sounds more like 'tttt' in ie600 while in 846 they are more 'dtdtdt'. When it comes to vocals, 846 is more echo-ey and nasal in comparison to ie600. Remember, these are exaggerated expressions for comparison purposes.

I tested all with apple dongle dac. My CTH gave hissing sound to ie600 and 846, not sure if its the amp or iem's sensitivity.

Song testing :


> Ciel errant by Alcest; Storm by GY!BE (non flac file)

In Ciel errant, where the distortion guitar kicks in at around 3' , the song felt artificial. The vocals in background is way too back to the level of being almost inaudible. I had to take the iems out the first time and check if something is wrong with connection. It maybe a case of mids being recessed by bass and treble. With this experience, I tried to 'critically' listen Storm by GY!BE. I was expecting the south Indian wedding pipe music at 4.30' to be muddled similarly since a lot of instruments are at play in background. But it played just fine.

> Ciel errant by Alcest, Storm by GY!BE (flac file)

Ie600 played both fine. I don't know what to take from this. I have had those songs on my phone for so long n I never felt this way while listening with N3. I think, I will just say that ie600 needs better mastered songs to bring out the full potential (?) and are not very forgiving to rest. With this experience, I moved the comparison only to flac files.

> Caspian - Hyms of the greatest generation (flac)

This song starts with a very acoustic sounding strings at the start where you can hear the clanking sound along with main notes. With ie600, it feels like very poor mixing since it elevates the clanking sounds but not with N3 or 846. Thus, one of my favourite song is rendered artificial with ie600 which sucks.

> South London forever - Florence + the machine

With ie600, the 's', 't' etc. in her voice are so damn prominent. With this song, I found the iems quite sibilant. With N3 and 846, this issue was not there.

Conclusions

In general, ie600 is a bit treble heavy for me. I can't use it for longer sessions. There are many times where I find them really nice but they are more one off than universal for my preferences. Also, this is my first time reviewing so do take my views from that perspective.

Review Of The Sennheiser IE600​

Introduction​

Sennheiser, A German company that has been in business since 1945 and is well known for providing high-quality studio and professional electro-acoustic products like speakers, headphones, and in-ear monitors has outgrown its capacity to produce these products and has turned to more reasonably priced options in order to reach a wider audience of customers while still maintaining the promise of current-day true superior sound quality. They flourished in this market because they are renowned professionally for high-quality microphones and other electronic equipment like Bluetooth headphones and earbuds that are more geared towards a customer-friendly approach. Nevertheless, being an audiophile, I am more interested in IEMs and headphones, thus I will be examining their mid-level IEM, the IE600. But first, let's discuss certain concerns before evaluating.

Disclaimer​

*Since I received this unit from my fellow audiophile Pulkit Dreamz, I am grateful to him. And as I've said in all of my evaluations, the same is true for this one: all of the concepts I've expressed below are entirely my own, original ideas that haven't been influenced by anyone else. If interested, go to this link.
*I am not associated with the connection, and I receive no financial assistance from anyone.
*For the remainder of the review, I will refer to these IEMs as "IE600."
*I am using different Ear-tips for convenience and better versatility.
*Finally, I will only evaluate the IE600 based on their performance, even though I will explain how it feels and seems physically and aesthetically.

Specification​

The IE600 is a single dynamic driver IEM. The driver it houses is what they call a TrueResponse transducer which is a 7mm driver. The shell is made of zincronium alloy and the nozzle front is made of plastic. The shell feels very rigid and strong and feels a little heavy on hands. The fit on the ears was comfortable and non fatiguing despite being heavy. The shell are constructed in a way that they help produce exceptionally neutral sound thanks to their dual resonator chambers D2CA. The coonectors used are gold plated mmcx and the cable it comes with is a para-aramid reinforced cable available in 3.5mm or 4.4mm termination stock. The problem the cable is very microphonic, but other than that I am happy with the cable. Other than the cable, accessories include three pairs of silicon eartips(small, medium and large), three pairs of foam eartips(small, medium and large), a premium carry case, cable clip, cleaning tool and a cleaning cloth. Coming to the technical specifications, the impedance is and the sound pressure level is 118dB. The frequency response is from 4hz to 46.5kHz and the total harmonic distortion is less than 0.06%.

Sound​

The IE600's sound has a more neutral, sub-bass-boosted inclination than a true V-shape sound signature. Anyway, these sound surprisingly good tonally. The midrange and lower treble are very upfront in this fundamental spectrum, but the bass is very punchy, hits hard, and resolves almost immediately. The midrange is also very melodious and energetic.

Treble​

The IE600's treble is very well extended, has a lot of air to it, and sounds spacious when the tonal balance is right. The treble is lively and serves a purpose in the detail department that is obvious. Female vocals in the higher octaves have a very full and rounded sound, while the upper treble is smooth. On the other hand, the lower treble has a more forward, tidy, and sparkly sound. The instruments have enough room to express their own will while still sounding right and present. Sounds like guitars, cymbal crashes, snare hits, etc. are exposed with enthusiasm. Overall, they don't let me down in this area, but if I had to pick something, it would be that on some tracks, the energy in the lower treble and upper mid-range, especially in female vocals, becomes a little too much, making the music sound a little hot.

Mid Range​

The mid-range is very well established in this spectrum and stands out in the mix for how neat and lively it sounds. The upper mid-range is very upfront and detailed in the mix. That the upper mid-range, despite being very engaging in the mix, still sounds non-offensive—that is, there is no shout, no harshness, or sibilance—amazes me. The female vocals do have a hint of heat to them, yes. Each audio component closely resembles a natural reproduction and sounds alive. Everything, including the acoustic guitars, violins, piano, and others, sounds so natural and authentic. The lower mid-range is slightly pushed back, which I think introduces lean characteristics and makes the vocals a little hot. In my testing, I discovered that this trait is almost nonexistent. I'd say the mid-range is exceptionally well done, very organised, and enthusiastic in terms of the overall performance.

Bass​

The bass is delivered with compulsion and authority. This doesn't mean the bass is very substantial in the mix; rather, it just means it moves quickly but effectively. Although the mid-bass has enough weight to be heard, the sub-bass is given more prominence in the bass. The bass is very powerful and has a significant impact on me. Although it almost sounds thick, the tone is very pleasant and recovers very quickly. The bass slams are almost perfect, and the kick drum hits are submissive. It reproduces sounds very naturally. Yes, the mid-bass extends into the lower mid-range, giving the mid-performance range's a more rounded edge. Overall, the bass response is excellent: deep while extreme, powerful hits with quick recovery.

Technical Performance​

The technical performance of IE600 is outstanding. While being extremely wide and tall in all directions, the soundstage is well orchestrated. The layering and imaging are both very distinct and sharp. The separation is extremely accurate and thorough. Details are strongly retrieved while the resolution is overly achieved. And for a 7mm transducer, speed is extremely quick. The IE600, in my opinion, is the Usain Bolt of the Mid-Fi market.

Soundstage, Sound Imaging & Separation​

Every vocal or instrument is placed specifically in the right place in the carefully staged, wide and tall, in all directions 3D holographic representation. With everything being distinct and the imaging and layering being sharp, I can identify each fundamental component of the sound and determine which instrument is closer or farther away thanks to the separation. Very nicely done.

Speed & Resolution​

The resolution is overly achieved, which can be good or bad and depends on personal preference, leaving the Mid-Fi segment behind and competing with higher-end IEMs. Excellent detail retrieval is provided. I'm amazed at how quickly notes recover because the attack and decay are so fast for a dynamic driver.

Conclusion​

Sennheiser has made significant progress with their IEM lineup, and with the introduction of the IE600, I can confidently predict that they will begin to dominate the IEM market. The IE600 is the best IEM I've heard in this category, so I can easily recommend it to anyone looking for a neutral sound with fantastic bass response and a clean presentation overall.

Sources And Tracks Used​

Sources​

Apple iPhone XS Max
LG G8X
iPad (4th generation)
Apple Dongle Dac
Shanling UA1 Pro
iFi HIPDAC
Venture Electronics Megatron
Apple Lossless
UAPP
Locally stored Flac and Wav Files

Tracks​

Curtis Mayfield - Pusherman
Earth, Wind & Fire - September
Earth, Wind & Fire - Let's Groove
Boston - More Than A Feeling
Fleetwood Mac - Everywhere(Remastered)
Toto - Africa
The Police - Every Breath You Take
George Benson - Affirmation
Daft Punk - Doin' It Right
Daft Punk - Derezzed
Daft Punk - Tron Legacy (End Titles)
GOJIRA - Amazonia
The Mars Volta - Inertiatic ESP
Fergie - Glamorous
50 Cent - In Da Club
Jay Z - Holy Grail
Erbes - Lies
Nitti Gritti - The Loud
Juelz - Inferno

Currently one of my absolute daily drivers (beside Sony M9)
my personal choice for 2022's best iem release


Build & Fit : housing is made to last with very small and ergonomics shape, yet the cable and eartips are not as good
- the stock eartips has a layer of foam, somehow using a very easy to collapse thin material sounds congested and very bassy using their stock silicone tips
- cable is not really flexible, and my main problem is the propietary mmcx, the pin is similar to other mmcx, yet it has a small mount that makes other mmcx cannot be easily connected to the pin, and i hate the earguide (every time i wear them i need a small time to adjust it)

sound : now here comes the good things

(yes my unit's channel matching is essentially perfect!! good job sennheiser)

i would categorize their sound as V shaped, by measurement alone it has a LOT of bass boost
but from real life perception somehow it is not as big as the measurement suggest

they are very tips dependent also, the stock tips somehow does sound a bit too bassy yet 3rd party eartips like spinfit, final type e, accoustune aet08 will give more balance presentation

bass has a very good sub bass depth with good rumble and dynamics, every song sounds fun and exciting, orchestral music like two steps from hell - never give up on your dreams sounds superb with majestic rumble

midrange might not be the most elevated frequency here, yet what i love is they are tuned correctly in terms of portion and balancing for male/female voices, piano, and guitar on middle octave sounds natural and well balance, i do perceive some brightness coloration from the treble elevation, making some S word has an extra air and gives a bit of brightness tinge

treble is very exciting with a lot of airiness, impact, and extension (the default stock silicone tips somehow limiting the air)
violin, percussion, cymbals sounds really lively, impactful with a lot of bite that is just enough to make them exciting without sounding harsh, trying lindsey sterling - dance of sugarplum fairy has never sound so good, also la primavera from vivaldi's 4 spring

honestly the treble is a very sensitive area, incompatible eartips or incorrect seal and depth will results in too spicy treble

the very special thing about this ie600 is how lively, dynamics, and impactful they are but still sounds coherent and natural, hearing bands and orchestra really takes me back to the time when i was still active in band and choir, the emotion is flowing abundantly, i could hear the emotion and soul from the music

for a single DD the technical is mind blowing, a lot of details and very high in resolution, solid note definition, also good 3D presentation, maybe the only downside, it doesn't sound as separated or as wide as some multi driver competitors

quick comparison:
vs zen pro : ie600 sounds more energetic and resolving yet, zen pro sounds more neutral and calm, but could be bit boring for me

vs softears twilight : ie600 sounds brighter, more lively, with more sub bass rumble, resolution and detail is also better, twilight has softer, thicker and laidback presentation, but it has more natural vocal and much wider soundstage

honestly as a 1DD lover i love em all, but for now maybe because of my playlist for orchestra and movie soundtracks, i feel more satisfied with ie600

vs moondrop s8 : ie600 has better sub bass rumble, more energetic treble and less shouty midrange, s8 has more noticable ba timbre, more shouty and forward midrange, better separation, resolution are about the same

vs clairvoyance : ie600 has more dynamics and impact on the treble also sharper note definition and resolution,
clairvoyance sounds warmer, more relaxed, with much bigger soundstage

vs IE900 : ie600 simply has better vocal presence due to more elevated pinna gain, while ie900 has too little ear gain pushing vocal and sound more distant, also even technically ie900 is definitely better in all area including better bass texture, but it somehow sounds sharper for me and i do pick more sibilances, so i do prefer ie600

vs ier M9 : ie600 has much better dynamics and impact, deeper rumble and higher treble extension, yet in soundstage, separation, and imaging, ie600 become a dwarf compared to M9's monstrous pin point imaging, M9 sounds much more calmer, warmer, and more neutral

for my personal choice M9 and ie600 completes each other depends on my moods

ie600 takes me out for a thrilling adventure
M9 takes me back to a comfy home

i've tried a lot of iems with much higher prices, but for now i think i could rest for a while with these 2 as my favorite

bonus photo, the only iem i bring during my holiday to bali

TL;dr: Color me impressed.

I got to hear these as part of the IE600 tour, and they're now on the way to the next listener. Thanks @ericpalonen for the loan. Opinions here are subjective, unvarnished and unquantified.

I'm not going to bother with the company, packaging, accessories. I'm pretty sure you've heard of Sennheiser, and there are plenty of photos around. You're certainly not getting these IEMs for the box.

Specs from the Sennheiser site:
Transducer: Single Dynamic Driver, Pressure Chamber
Frequency response: 4-46,500 Hz
Sound pressure level (SPL): 118 dB at 1 kHz, 1 Vrms
Total harmonic distortion (THD): <0.06% (1 kHz, 94 dB)
Cable length: 125 cm
Connector: Fidelity (+) MMCX
Impedance: 18 ohm system impedance
Attenuation: 25dB

You'll have to ask somebody's dog about that 46.5 kHz frequency response-- I'm only human!

Let's talk about what matters most: Fit, Cable and Sound.


Fit

These are the same form factor as my own IE300 (and other Sennheiser IEs). It's a small oblong/rectangular hybrid that should tuck into just about anyone's ears easily. With metal housings, the IE600 are a little more substantial in the hand than the plastic IE300, but they still pretty much vanish in the ear. Light and unobtrusive.

But there is something unusual about the way Sennheiser IEMs fit.

With most IEMs, I use large eartips and push them in as deeply as possible to get a good seal. Sometimes foam, sometimes silicone, but without a deep fit there's no isolation or bass for me.

These are different. I tried a lot of my other tips with these, but I came back to Sennheiser's included L silicones because they are the only ones that worked for me. (The package includes S-M-L silicones and foams).

There's a trick with the IE300 and with these. The Sennheiser tips have an extra groove inside their sleeves, so you can put them on the nozzles in two spots: pushed all the way onto the nozzle or about 2mm up from there.

Large silicones, on the notch away from the base, were the only ones that worked for me -- and absolutely everything else sounded tinny and pathetic. You get a seal or you don't. Also, and crucially, instead of deep insertion with the silicones, I pulled back slightly once they were in my ears. There's exactly one spot where the soft silicone completely conforms to the ear canal. And at that spot....yes!

Just don't expect to seat these like your other IEMs. They work their own way to get the ideal fit.

Also, you need to rotate them just so on the MMCX connection. The cable has a stiff memory hook around the ear, and it can fight with you, trying to pull them out. That cable!

Cable

Sigh.

The 3.5mm SE "para-aramid reinforced" cable looks and feels the same as the much-derided IE300 cable, and the IE600 also comes with a 4.4 balanced cable of similar construction. (The para-aramid family of plastics includes Kevlar, but perhaps for trademark reasons Sennheiser doesn't use the word.)

I hate the cable. On the plus side, it's light, and Sennheiser has said it's made to be durable; the same cable on my IE300 is going strong after more than a year. BUT: It is seriously microphonic and it has nonstandard, recessed MMCX connectors. So you're stuck with the noisy OEM cable unless you want to pay $$$ for one of the few aftermarket replacements -- and then hope that they are less microphonic. Why Sennheiser made this new unit with the same annoying cable baffles me.

Using the 3.5mm cable, I listened to Tidal Masters and my own downloaded or ripped 192k/wav/FLAC/mp3 files on Foobar2000 and Vox, both from my MacBook Air headphone jack and via my VE Megatron DAC/Amp. I also played FLAC, hi-res wav, CD-quality wav and mp3 via 3.5mm SE from my A&K AK70.

With the 4.4mm cable I listened to Tidal Masters and my offline files via the VE Megatron. There's plenty of volume without amping. The sound from the Megatron was an improvement -- more open and realistic -- but I can't specify whether that's a result of the DAC or the amping. Single DD with 18 ohm impedance probably didn't need an amp.

Considering the cable changes and volume matching it would require, I'm not set up for any detailed comparison of SE and balanced. Perhaps someone else on the tour can do that.


SOUND:

Ahhhh, yes. It's impressive. Without looking at graphs, I had guessed that it's a W tuning: deep bass, upfront vocals, extended treble.

I threw a lot of things at the IE600: African and trip-hop subwoofer madness, Bach and Stravinsky and Messiaen, jazz, organic roots-rock and Americana, thrashing metal, vintage soul, future-R&B, sparkling Laurel Canyon productions, low-fi indie-rock, high-density prog-rock, New Orleans brass bands, subliminal-noise Nine Inch Nails, extreme-bass Hans Zimmer soundtracks, grimy low-fi hip-hop, otherworldly ambient, whisper-to-crash Billie Eilish.

I also ran the test tones from audiocheck.net -- no big peaks or troughs --- and, for spatial cues, tried the Abyss video on YouTube.

It's hard to trip up these IEMs. Not impossible, but not easy.

Bass is extended and precise; the lowest notes retain pitch as well as impact. The bass drum that opens Feist's "The Bad in Each Other" goes straight to the solar plexus, and so do the thuds and swoops of Amazondotcom's "Gut Ritual." In "Angel" by Massive Attack, the pitch is undistorted enough to clarify that the bass notes at 0:07 are microtonally lower than the ones that start the song.

Vocals, male and especially female, seem slightly pushed upfront, along with midrange instruments. If you're trying to pick out lyrics that's often a plus. David Bowie's "Sue (Or in a Season of Crime)" surrounds him, in the same register as his vocals, with a jabbing guitar riff and a saxophone panning around the mix. But his voice still holds the center. In a weird mix like "Here She Comes" by the Beach Boys (from "Carl and the Passions -- 'So Tough'"), the lead vocals in the later verses (around 1:54) aren't exactly prominent, but the IE600 gives them a fighting chance.

Beth Orton's voice hovers unforced above the piano and percussion of "Haunted Satellite." Billie Eilish's "Bad Guy" really skulks along in the bass, yet without any intrusion on her breathy voice ("duh!"), and the IE600 also beautifully details how staggered all the overdubbed fingersnaps are. It's even possible to decipher Thom Yorke's rant in the Smile's "You Will Never Work in Television Again."

A well-recorded string quartet -- how about the Emerson playing the Allegro attacca from Bartok's String Quartet No. 3 -- sounds bracing on the IE600, and brasses and saxes gleam.

The IE600 puts some air around each instrument; there's treble extension to match the bass impact. Transparency is the priority, more than warmth/blend. Personally, I'm a big transparency fan. A piano-and-percussion duet like "Fititi Nongo," by the Cuban pianist David Virelles, neatly delivers all the rhythmic crossfire it should. Everything Lindsey Buckingham picks and strums on Fleetwood Mac's "Go Your Own Way" shows off distinct timbre and transients, while the backing vocals hop in and out.

In Paul Simon's "Can't Run But," the fitful percussion and J. J. Cale's guitar curlicues glimmer throughout. The percussion that's spread across "On the Corner" by Miles Davis -- trap drums, tabla, cowbell, congas -- is differentiated and distinct. And every scurrying piccolo and clarinet in Valery Gergiev conducting Stravinsky's "Rite of Spring" streaks brightly through the pagan wilderness.

But there are also downsides. For styles like thrash and death metal that feature high-speed, distorted rhythm guitar, the IE600 seems to spotlight the buzzing top end of the distortion instead of the thrust of the chords. Or in a song like Sylvan Esso's "Moving," with a lot of sizzling synth tones, the IE600 seems to emphasize the hissiest frequences. The IE600 isn't going to smooth out any extremes of a recording. And if you're sensitive to sibilance, the IE600 are likely to trigger you unless you dial in a different EQ. (I didn't play around with EQ, though I would if I owned the IE600, taming the treble and maybe rolling off a tiny bit of bass.)

The bright treble improves positioning, of course. Some three-dimensionality was audible when watching the Abyss video, though more width than depth and more depth than height. (Too bad the lossless download from the @Abyss YouTube page doesn't sync with the video.)

Listening to music files that are better quality than YouTube, there are plenty of spatial cues -- certainly in the round if not fully spherical. "Lonely," by Koffee, has that thick reggae bass, but it never masks the rimshots or hi-hats; tom-toms roll across from left to right, and the placement of organ, piano and backup voices is well-separated and precise. In "Jele," from the "Black Panther: Wakanda Forever" soundtrack album, I turned to look around at 0:59 where Busiswa suddenly shouts her entrance.

All in all, the IE600 is an IEM that makes good on its obvious intentions: full-spectrum response with an emphasis on revealing as much as possible, plus a little bit of fun at the extremes.

Comparisons: Well...I don't have any other IEMs in this price range. My Venmo is...j/k.

Sennheiser IE300: Simple -- the IE600 outdoes the IE300 in every way (as it should at 3x the price). I like the timbre on the IE300, but it has a pushy, exaggerated bass. That's especially obvious when compared to the IE600, which hits the same notes but keeps them more in proportion. The IE300 doesn't match the lucid high end of the IE600, either; it sounds more constrained. I guess they had to save something for the upgrade. For what it's worth, the vent hole is differently shaped and differently placed on the IE300 and IE600, which may account for some of the increased openness.

Tri I3: Included just because they're my other favorites among my IEMs, the original Tri I3 (not Pro) make an interesting contrast to the IE600. They're a tribrid -- DD, BA, Planar -- that begs for more power than the single DD IE600. With a more restrained treble, they don't spread the instruments as widely as the IE600 or provide the last bit of crispness on percussion. On the other hand, despite the multiple drivers, they do seem to bind a mix together. I'd say the Tri I3 is the huddle, while the IE600 fans out the instruments for the play.

The list price of $699 is a serious investment, and without comparing others in that price tier I can't say whether the IE600 is a good value proposition -- though it's a good-sounding IEM. I'll also note that the Sennheiser IE300 quickly dropped in list price from $300 to $200. An equivalent price drop for the IE600 would take it down to $466, which wouldn't be a bad thing, so you might want to wait a bit before pulling the trigger. (It could help pay for replacing the cable.)

All in all, a very enjoyable sound, nicely positioned between analysis and oomph.

IE600 vs A8000
An Audio Comparison by Bosk



This is an audio review twenty years in the making.

How the world of portable audio has changed in that time. I’ve watched it grow from humble Apple iPods and single BA-driver Shure earphones representing the pinnacle of portable fidelity, to a scarcely recognisable landscape where hybrid IEMs worth the price of used cars tower over a horizon dotted with digital audio players as sophisticated as they are weighty.

In many ways the earphones I’ll be comparing (both comprising single dynamic drivers & featuring minimalist aesthetics) are throwbacks to an earlier era as I am in some ways myself – unlike many of you I listen mostly to offline files and have a confessed preference for single-DD IEMs thanks to their unmatched timbral accuracy & coherency.

Can single-driver IEMs ever hope to compete with hybrids containing BA & EST drivers on technical grounds, and do their strengths outweigh their shortcomings? These are compelling questions but you won’t find them answered here. Instead I’ll merely state if top-tier technicalities are a requirement of your next IEM purchase then neither of these earphones may suit you as their strengths lie elsewhere.

Enough preamble, I’d best make a start.

Two months ago I found myself at Addicted to Audio in Melbourne with a pair of Andromeda 2020’s in my pocket that had impressed but never fully satisfied. On the counter sat a triplet of alternatives– the IE600s, IE900s and A8000s.

To my surprise the IE900s left me cold. Immediately apparent was their stereotypically sucked-out Sennheiser midrange that rendered instruments with unnatural hollowness, a trait I felt even their impressive sub bass & broad soundstage couldn’t excuse.

The IE600s by contrast seemed far better balanced, indeed their standout quality was that nothing stood out as wrong. The A8000s I immediately recognised as bright and lively, with a character reminiscent of the Dunu Lunas.

I walked out after purchasing the IE600s. They felt the safest choice, indeed “the safest choice” might well be an appropriate epitaph for their tombstone. Yet though they satisfied admirably in the weeks that followed, my mind kept returning to the sound of the A8000s. So despite being content I did what any self-respecting Head-Fier would do - buckled under the weight of my own excessive cravings and purchased a pair.

Was it a mistake or was the decision justified? Read on, and we may both learn the answer.





Sennheiser IE600

The Sennheiser IE600s are quite possibly the easiest IEMs in the world to recommend to anyone willing to spend USD $700 on earphones.

They do virtually nothing wrong and a great many things right. To begin with they’re very well made and feel remarkably durable. Others have said their Zirconium shells feel more pleasant to the touch than those of the IE900s, and I agree. Their form factor is vanishingly small and as a result it’s quite easy to forget you’re wearing them. Their recessed MMCX connectors are a problem (not all aftermarket MMCX cables fit) but Effect Audio’s CONX connectors play nicely with them which is some consolation.

Sonically the IE600s are magnificent all-rounders which perform well with every genre of music. None of the three major frequency bands stand out as manifestly inadequate in proportion to the other two, though other more ‘specialist’ IEMs can deliver vastly higher amounts of bass, midrange or treble by comparison. What those give up is the even-handedness of the IE600s in which balance between frequencies is always tastefully maintained.

Indeed the IE600’s major strength can also be considered their primary weakness. That sonic balance & corresponding restraint preventing nasty frequency spikes from jutting through the clouds can leave the sky bare of contrast. Which is not to say the IE600’s lack dynamics, rather there is a slight flatness of presentation leaning towards politeness. Not enough to cruel musical enjoyment for the overwhelming majority of albums, but a tendency nonetheless.

With regards to technicalities the IE600s occupy a rung towards the higher end of the single-driver DD spectrum but not at the very top. Their soundstage, though not as broad as the IE900’s, is fairly wide though disappointingly flat. Dynamically they’re quite strong, and imaging is decent. Resolution is above average by single-driver standards but appreciably below TOTL hybrids, but in compensation their coherency is superb and their timbre very good, but perhaps lagging slightly behind warmer single-driver IEMs with weaker technicalities. Rarely does one listen to the IE600s and feel resolution is lacking, as any absence is more easily noticed through direct comparison to more highly-resolving IEMs.

The IE600s are difficult to fault, and are only rendered inadequate in comparison to TOTL hybrids which lack their coherency (to say nothing of being physically larger) or specialist IEMs which may do one particular thing better but others worse.





Final Audio A8000

If my description of the IE600s gave you a “solid, but not spectacular” vibe, the USD $2000 A8000s may be described as more spectacular but a less solid choice.

Significantly heavier & larger than the IE600s, the greater bulk of their stainless steel shells provides improved isolation and a more secure seal in my case, though they do not “disappear” when worn quite as readily.

The A8000s are famous for their pure beryllium foil drivers. Having owned the Dunu Lunas I knew what to expect – responsiveness substantially faster than other DD drivers on the market, which greatly aids dynamics and the ability to maintain control during complex passages of music, but may also lead to aggressiveness as the attack on the leading edges of notes becomes more pronounced.

This advantage leads to the A8000s being significantly more technically capable than the IE600s. Curiously the Sennheisers have a slightly wider soundstage, though the A8000’s is markedly taller and deeper. However in resolution & dynamics Final’s flagship pulls comfortably ahead, performing spectacularly in both areas above all other single-DD IEMs I’ve tested.

So much for the good. The ‘bad’ is although Final labels the A8000s as all-rounders eminently capable with any genre, their tuning is liable to polarise opinion and compromise their ability to reproduce all genres satisfactorily.

Compared with the IE600s which are extremely balanced across major frequencies, the A8000s feature deeper & more pronounced sub bass but substantially less midbass. Their lower midrange is less prominent resulting in less warmth added to the presentation, but the upper midrange & lower treble are boosted significantly. The net effect is the A8000s have what might be labelled a traditional reference sound signature, with an upper midrange & lower treble emphasis. It is a flavour suiting some genres better than others.



IE600 vs A8000

Broadly, the IE600s feel like an extremely well-tuned jack of all trades that tread a delicate line between greater technical proficiency on the one hand, and greater musicality on the other. They excel at getting out of the music’s way without calling excessive attention to themselves, yet deliver enough detail & dynamics across a wide enough stage that you aren’t left feeling anything essential to the performance is missing in the way you might with cheaper single-DD IEMs that lack technical chops.

The A8000s are a different beast entirely - far less well-rounded and accepting of compromise. Instead they have a voice of their own, yet it is their colourlessness which colours their performance. Music on the A8000s feels stunningly clear, precise and correct, down to the smallest detail. Meanwhile their tremendous dynamics and prodigious sub bass prevent the feeling of flatness or lack of gravitas sometimes accompanying reference-tuned transducers.

Unfortunately this laser-like precision is extremely unforgiving of poor recordings. To make matters worse the A8000’s presentation is extremely upfront, seating you directly on stage next to the performers (RIGHT NEXT TO THEM) as opposed to the IE600 positioning the listener a more ‘sensible’ five or six rows back. IE600 notes are also more rounded, and the presentation correspondingly gentler.

Vocals on the A8000 for instance, both male and female, will leave you hearing every miniscule nuance in the singer’s throat, and the images produced by individual voices & instruments feel noticeably larger than those of the IE600. The A8000’s remarkable speed also means instruments retain detail & remain distinct even when many are playing, whereas the IE600 becomes overwhelmed by complex passages far more commonly.

One disadvantage of the A8000’s tuning is they often perform poorly on rock & rock-based pop music. Where the IE600s will pleasingly smear notes together to create a sense of groove & rhythm, the A8000’s absolute insistence that every note from every instrument MUST be distinct (even those comfortably residing in the background on other IEMs) can be fatiguing, and lead to such albums sounding clinical.

With classical music or movie soundtracks the tables are turned, and the sheer precision of the A8000 becomes a wondrous joy to behold. Symphonic works are especially good, as the thundering sub bass, superb dynamics, and breathtaking delicacy with which string instruments are portrayed elevates performances to levels I greatly doubt any other single-DD IEM can match, or perhaps any IEM in the world at all.

Electronic music is more of a mixed bag in the hands of the A8000s. Superb sub bass, dynamics and detail can lead to breathtaking performances, but the upfront and aggressive upper midrange can accentuate even the minutest harshness present in recordings. As a low-volume listener I solve this by simply backing off below my usual level, but anyone accustomed to dangerous decibels may experience a ringing effect impossible to ignore.

However regardless of genre there are key differences in the presentations of both earphones.

The IE600, though not what I’d call laidback per se, are far more sedate. With warmer air between fuzzier notes stretched across a wider stage, they’re fairly non-fatiguing and easy to tune-out to when working whilst listening, yet engaging enough to convey the gestalt & emotional tone of a performance.

Whereas the A8000s invariably compel attention, delivering everything all at once in a manner that excites and occasionally overwhelms, bringing music to life with unrelenting, unwavering energy.



Selected Comparisons

The following tracks were compared with both IEMs many times. My favourite Azla Sednafit tips were used, source was an iBasso DX240 with AMP1MK3 amp card, and all tracks were played locally through Mango OS via a 512GB Micron WT micro SD card. Cable was an MMCX Effect Audio Ares S. I also tried an EA Cadmus but greatly preferred the warmer copper timbre of the Ares S with both IEMs.




Comparison #1 • Van Morrison – Crazy Love 24/192

The acoustic nature of this track suits the A8000 very well. They render guitar plucks with supreme delicacy, contrasted with the bassline which is firm and deep, while Van Morrison whispers with an ethereal crispness.

Moving to the IE600s, the performance feels a half-step slower and more relaxed. More space surrounds Van Morrison’s voice which is projected slightly louder & more distinctly from the surrounding instruments, spotlighting him as the star of the show whereas on the A8000 everything onstage jostles for attention.





Comparison #2 • Anne-Sophie Mutter & John Williams – Marion’s Theme 24/96

This gorgeous song from Raiders of the Lost Ark is brought to life through Anne-Sophie’s dominating violin. On the A8000s I am riveted by her performance, spellbound by the eloquence of her playing… every subtle nuance of which is rendered devotedly, which remains distinct from the rest of the orchestra at all times.

On the IE600s her violin blends in with the surrounding instruments much more, and I find myself more easily swept up in the great swells of the orchestra, as the general thrust of the performance carries me along at the expense of marvelling at her singular virtuosity.





Comparison #3 • Yello - Drive/Driven 24/48

My favourite Yello track from their 24bit 40 Years compilation, Characterised by romantic longing in the eternal vastness of space. The IE600’s wider stage lends the performance a cavernousness filled with warmer, smoother notes that help project an enigmatic nostalgia.

On the A8000s everything is sharper and more resolved, stifling the rhythm as details which should be tastefully relegated to the background grab excessive prominence. Bass may be deeper & tighter, but the guitar is rendered with such bite it becomes quite distracting.





Comparison #4 • Michael Jackson - Billie Jean DSD64

Always a great test track, the DSD version is especially good. The IE600’s flatter, wider soundstage presents a slower, more subdued bassline with less upper midrange & treble sparkle, allowing Michael’s voice to be rendered in a pleasantly well-rounded fashion.

Switching to the A8000s yields a more exciting V-shaped presentation in which the nuances of each instrument are accentuated, including the maracas which recede into the background on the IE600s. Michael’s voice verges closer to sibilance on the A8000s, but with that comes a greater articulation & distinction from the surrounding notes.





Comparison #5 • Fleetwood Mac - You Make Loving Fun 24/96

A great recording from a classic album, the pulsating bassline dominates the A8000’s rendition in which shimmering cymbals and piercing guitars clamour for attention, compelling me to actively listen to every measure.

The IE600s take several steps back from the stage, offering a more laid-back rendition in which notes are more rounded and blend together harmoniously, encouraging me to relax and let the groove wash over.



Conclusion

Great art challenges our assumptions and asks questions of us, so I ask this – what makes an earphone great?

Is it the uniformity with which it capably reproduces music of all varieties, or do we only measure the peaks and ignore the troughs?

Clearly these two IEMs were born of different goals, the one to illuminate equally and the other to shine brightest and cast deep shadows. The IE600 will satisfy a vastly larger audience, whilst the A8000 selectively radiates more powerfully.

Having resolved at the beginning of 2022 to become a serious classical listener, I’ve found the A8000s a worthy investment. Yet few earphones could highlight their shortcomings as all-round performers as the IE600s have… in the end does it matter? Perhaps if budgetary constraints or a commitment to minimalism confined me to a single choice it might, but as matters stand perhaps not.

Twenty years ago it was normal to expect a single set of earphones to do everything, because our expectations of what they could do were substantially lower. Now manufacturers produce models with wildly different flavours, abandoning the precept that a single IEM must be equally at home in the concert hall or mosh pit as it is on the dancefloor.

The A8000s are special. The IE600s are safer.

The Sennheiser IE600 have been loaned to me directly by Sennheiser as part of a tour that was arranged here on Head-Fi. The terms of the tour were that I would spend a maximum of 2 weeks with the IEMs, posting my honest opinions of them on Head-Fi at the end of the period. The also requested that any other reviews or comments on social media contain the hashtag #IE600Tour so they could be easily found.

There were a couple of other requests (such as at least trying the stock tips and comparing them to any other tips used, etc.) which you can find by visiting the first post of the Tour thread here: https://www.head-fi.org/threads/on-the-road-again-announcing-the-ie-600-tour.963163/

No other requests have been made outside of the above thread, therefore, I will do my best to be as unbiased as I usually am, taking into consideration that it has not cost me anything to try out these IEMs.

Rather than sharing a specific official page link, I suggest you use this link: https://sennheiser.com/ which will take you to the relevant Sennheiser page for your location, from which you can navigate to the IE600.



Intro…

While I am someone who has been using Sennheiser gear for a very long time, due to me working in the pro audio field, I really haven’t had the chance to try any of their more hifi orientated IEMs. I have tried plenty of the consumer class stuff, along with plenty of their stage focused stuff, but the IE series is something that I just haven’t come across before.

I was very tempted to pick up the IE300 when they were released, to get a taste of what Sennheiser were doing with this line, but in the end I ended up not doing so. I was also interested in trying out the IE900, the TOTL in this series, but the price tag is something that doesn’t make it easy to blind buy.

So when the IE600 was released, priced at just under 600€, I was interested in finding out what they were all about and, when Sennheiser announced the tour, I was very happy to make the selection of people to get to try them.



Presentation…

The IE600 comes packaged in a very professional way. Upon opening the outer box, the two IEMs sit in a foam surround, which either makes the IEMs look tiny or the box look huge!

Beneath this top layer we find multiple documents, user manuals etc. and below these we get to the accessories.

The accessories included are 2 cables, one 3.5mm and the other 4.4mm, a square transport case, 3 sets of foam tips, 3 sets of silicone tips and a cleaning tool.

To be honest, the included accessories are what I would consider to be just the correct amount. There is nothing missing that we need to enjoy (and look after) the IEMs but at the same time, there is nothing included that is just to fill a void (except maybe for some of the packaging itself).

Balanced and unbalanced cable options are included, a nice travel case that is not overly large is included, basically offering a presentation that I would consider very well thought out.



Build and aesthetics…

Starting off with the IEMs, they are small and fairly lightweight (although they could be considered heavy for their size I guess). Completely made of what seems to be some kind of sandblasted metal, they look rugged and discreet at the same time. When wearing them, they are even more discreet, as they fit inside the ear very well, sitting flush inside the ear (at least in my ears).

Speaking of comfort, I find them to be probably the most comfortable IEMs that I have ever worn. Recently I said that the Airship were one of the most comfortable sets of IEMs that I had worn in a long time. Well, the IE600 came along and blew those out of the water as far as comfort.

Added to the comfort of the IEMs, there comes the cable. While I wouldn’t say the cable is anything special, it’s just a simple grey cable, the mouldable hooks over the ears are great. This reminds me of the moldable hooks on pro gear, such as DPA mics, that are made to be comfortable and not move throughout a show, no matter what the artist is doing. However, in the case of the IE600, these moldable hooks are covered with a slightly thicker outer sheath than the DPA mics (for example), making them work even better in my case.

When inserting the IEMs at the beginning, you do need to fiddle around a little to get the perfect fit, but once they are in place and the hooks are moulded to the correct shape, they are extremely comfortable (for me) and are going nowhere unless I want them to.

The cable itself is nothing special, as I already said, which sort of keeps up with the “pro” functionality of these IEMs. I would expect to just run the cable down the artists back, connect it to the belt pack, and not have to worry about it.

One thing that may be a negative for some is the fact that, while the cable does use MMCX connectors, they seem to be Sennheiser proprietary connectors. This means that you can't just grab your favourite cable of choice and expect it to fit the IE600 (I believe this is the case with the IE300 and IE900 also). However, the connectors used are so smooth and so easy to connect/disconnect, without worrying about them being too loose or too tight, that it makes it almost worthwhile having to stick with the stock cable.

At the other end, while the 3.5mm/4.4mm is plastic, I have no doubt that it is also of great quality. I have Sennheiser cables that I have used thousands of times over the years and not once have I had to worry about the connector.

Another thing to point out, which I will discuss more in sound, is the included tips. These tips are also proprietary to the IE line of IEMs, as they include tuning material inside the actual tips. While I do know that some people have had issues with these tips, personally I find the included foam tips to be extremely comfortable and while I did try a few other tips, I also found that I preferred the sound with the foams.

The rest of the included accessories are of a quality that seems just as good and, while 600€ is not exactly cheap for a set of IEMs, I feel that the build of all of them are up to the standard of the price point.



Sound…

(Note: All tracks mentioned are clickable links that will open the track for reference in the streaming service of your choice)

As the IE600 is part of a tour (which goes back to Sennheiser between each person on the tour, for cleaning and replenishing with a new set of tips), I didn’t have to bother with putting it on the burn in rig for days to avoid the “it’s because you didn’t burn it in long enough” comments. So I opened the box, put them in my ears (marvelling at the comfort) and connected them to the Go Blu. Within 30 minutes, I had decided that these were the best single DD IEMs I have heard to date.

I have said many times in the past that I don’t put together any detailed impressions of things until I have been using them for at least 4 or 5 days as sometimes that period will either show more flaws that I hadn't noticed upon first listen, or even get me used to the flaws and dfind that I enjoy them more than I originally thought.

During these two weeks, I haven’t used the IE600 exclusively as other things need to be reviewed, but I did find that, apart from the exclusive use for 4 or 5 days, that any time I felt like listening at other times of the day, I reached for the IE600. That is already something that goes to prove my very positive experience with these IEMs. They are not perfect, I will get into details in just a second, but I still feel that the overall sound of these IEMs is very very good.

I have to say that when I put them on the measuring rig, I was very surprised at the results. I do remember noticing that they had elevated bass on the graphs when I first saw measurements of them, but measuring them for myself brought me to realize that either:

a) I have become a bass-head without realizing it.

Or

b) These do not sound like they measure.

Before moving on and explaining what I mean, here is the graph of the IE600 with the usual foam tips I use for measuring, along with the included foam tips (the ones I have been using) and the included silicone tips:



As you can see, the low end is way above my usual preference target, but as I have said in the past, if an IEM is capable of producing very clean and articulate bass while still being boosted, I will often find that I like the low end. And that is the case with the IE600.

Starting off with the subbass, we are almost 10dB above my preference on paper. Yet to the ear, this subbass only comes into play when the song needs it. The IE600 don’t produce subbass on their own, they just boost what is already in the track and, as they do it in such a clean and articulate way, they come across as impressive with many subbass tracks.

Putting them through the usual “Chameleon” test, there is a large quantity of subbass but there really isn’t an overly present sensation of rumble, at least not to the extent I would expect looking at the graph. The same happens with Lorde’s “Royals”, although this track does have a subbass that is a bit more “out of control” than “Chameleon”, which is due to the recording more than the way that the IE600 portrays it.

The midbass is where I usually suffer when a set of IEMs is overly boosted in the low end. An overly present midbass is something that I find tiring and can make me want to either stop listening or move to music that has less of a bass presence. With the IE600 I did not get this feeling. Again, it is clearly boosted in these frequencies, yet somehow manages to keep the bass clean and stop it from interfering with the lower mids.

Listening to “No Sanctuary Here” by Marian Herzog feat. Chris Jones, there is no lack of bass presence to make this track sound excellent in the lower ranges, yet it does not detract from other parts of the song.

Moving away from more electronic bass focused tracks and towards bass guitars, here I did find on occasions that the low end was not quite as clean or tonally correct as I would like. For example, “Black Muse” by Prince, where this particular track did give me the sensation that the bass was overly bloated, missing some of the clarity that this needs to appreciate the bass playing. The same could be said for other tracks such as “No Ordinary Love”, where the music is much simpler, allowing the bass to become a little too present. As soon as I moved back to more electronically focused tracks, like “Shot Me Down”, the bass went straight back to being great.

What the IE600 does do is keep the bass away from the lower mids, offering a transition that is much cleaner than I would have expected from such a tuning. In fact, the mids on these IEMs are nothing short of excellent on most tracks.

Even more simple and melodic songs, such as “No Ordinary Love” that I already mentioned, or “Billie Jean” by The Civil Wars (to move more towards the acoustic side of things), sound very balanced and well defined throughout the mids. The upper mids have a rise around 2kHz which, while maybe not the best I have heard, do a very good job of presenting these voices and instruments with detail and not too much harshness.

Acapella tracks, such as “Hallelujah” or even “Happens To The Heart" (which is not exactly acapella but almost), do sound clear and articulate, although, in the case of Leonard Cohen, I got a sensation that it was maybe not quite as smooth as it could be.

After the 2kHz mark there is a bit of a dip which, thankfully, does not come back with a peak at the 5kHZ mark like on so many other sets. I do feel that the presence just above 2Hz could have extended slightly more, maybe to just past the 3kHz mark, but that is just a personal preference and more of a nit pick than anything else.

As we get into the higher ranges, there is a bit of a peak that can suddenly appear now and again, giving the sensation of a bit of brightness that can come across a little harsh, such as brief appearances in “Sugar” by Francesco Yates. Sibilance is mostly controlled, although not eliminated, making “Code Cool” be just hovering on that sibilance mark, without actually getting there.

As far as soundstage, I would say that it is not huge, maybe at the higher side of average, yet the image placement and details make it seem like there is much more space than there actually is. With tracks like “Bubbles”, you can focus on literally any of the sounds and follow them, without ever getting the sensation that you have lost them. The same can be said for “Strange Fruit”, where each and every layer of vocals can be tracked on its own.

Last but by no means least, the detail. The details that this small dynamic driver is capable of presenting is very impressive. I never found that I was having to focus on anything to appreciate the details, yet at the same time, it doesn’t push them in your face. It just does a very good job of keeping everything just where it needs to be.



Conclusion…

I haven’t mentioned it during the review as I always share my opinions without EQ, yet, I find that with a little bit of EQ, these IEMs go from being very good, to almost excellent. I found that dropping the low end quite a bit (not 10dB to match my target but around 6dB), along with just a little tweak of the upper mids (to extend that 2kHz presence just a little more) really opened up these IEMs and made them sound amazing (in my opinion of course). Now, I am in no way saying that my little tweaks improved these IEMs, far from it, more that they adjusted them to my personal preferences.

Without EQ, these are still very good IEMs, with a performance that I find spectacular for a single DD, providing details that are way above what I expected. I am sure that others, who prefer more bass than me, will enjoy the tuning as is.

I also feel that the build, aesthetics, cable, accessories, everything really, is well thought out and is presented in a way that I doubt anyone could fault.

In fact, with the possibilities of EQ, I wouldn't hesitate to recommend these IEMs as on stage monitors to any of the artists that I work with. As each artist gets their own in-ear mix, the IE600 can be tailored to almost anyone, as there isn’t anything missing, just some people will prefer to drop certain frequencies more than others.

And then there is the comfort. If ever there was a set of IEMs that I would want in my ears for extended periods and just forget they are there, the IE600 are those IEMs.

(as always, this review is also available in Spanish both on www.achoreviews.com and on www.youtube.com/achoreviews)

All FR measurements of IEMs can be viewed and compared on achoreviews.squig.link

All isolation measurements of IEMs can be found on achoreviews.squig.link/isolation

DISCLAIMER - The IEMs were provided by Sennheiser as part of a review tour; all they asked in return was for my honest review. Thank you to @ericpalonen & @Sennheiser .


Most of my listening was done on the Shanling M6 Pro 21 using the 4.4 balanced cable w/the M stock eartips w/FLAC files on the microSD card. The IE600 has a fairly smooth tonality and pairs well with Shanling's house sound; a somewhat relaxed sound w/full-bodied & rich mids bolstered by a slightly boosted low end and an overall warm tone. Overall I found the IE600 to have a natural tonality with a fairly balanced signature. Mids are slightly pulled back in relation to the slightly boosted high & low ends, lending the IEMs a slight V-shaped signature.


Driveability
The IE600 is fairly easy to drive. By default I leave the M6 Pro 21 in High Gain mode listening out of the balanced port and found that setting the volume at 15 (out of 100) was well within my normal listening volume as well as being able to block out the din of the NYC subway system during my commute. I had actually mistakenly grabbed the single ended cable one day and found that I only had to increase the volume about 5 steps to reach the same listening level. Even at this low volume setting the DAP/IEM combo was able to pull out fine details in the music.


Ergonomics/Fit
Other than the balanced plug, the 3.5mm & 4.4mm cables have the same internal wiring. Overall I found the stock cable very nice to use. It is very soft & pliable and the extended ear hooks are very easy to shape over the ears. I won’t really comment on the fit as I feel fit is highly subjective; we all have not only different sized ears/canals, but also different shapes/angles/bends. In regards to size, I don’t see these as being an issue unless you have really small ears as the IE300/600/900 have truly small shells. The main issue I had was with the eartips & insertion depth/isolation. The new IE series utilizes a 2-step eartip placement; eartips can be placed just at the tip of the nozzle or pushed further in. For my purposes I found the best isolation/seal with the eartips on the outer position for maximum depth of insertion. I will say I found it tricky/frustrating at times as it is easy to push them into the inner position while inserting them in my ears as I do have fairly small ear canals. I had to utilize the ear pull method (pull on the tips/top of my ears while inserting the IEM) quite a bit. While I used the stock tips for this review, my preferred eartips are Sony hybrid tips which I found offered a more secure fit over the stock tips while still being able to take advantage of the 2-step placement.


Build
Overall the IEMs have a very solid build and the Zirconium Alloy body has a nice feel & density for the small size. Even though the nozzles are plastic, I actually prefer the IE600 shell to the machined shells of the flagship IE900 that are fairly easy to scratch with their aluminum build. The IE600 shells (6g each) actually weigh more than the IE900 shells which come in at 4 grams each (without cable). The understated shell color also belies their premium feel with a nice stippled effect.





Highs
Treble is fairly smooth and offers just the right amount of sparkle without exhibiting any sibilance. Not the tallest or airiest of stages, but detail retrieval is very good with sufficient air. Treble is never aggressive and is in line with the IEM's overall natural sound signature.


Mids
Once again smooth and natural, with a hint of warmth. I found the vocals to be on the more intimate side and enjoyed acoustic sets. Not to say the IE600 struggles with grander stages or full orchestral performances; individual notes are rendered well with sufficient spacing, but the soundstage isn't especially wide so it is much more suited to vocal oriented & again, more intimate performances.


Lows
Bass is slightly boosted. It reaches fairly low with a fair amount of sub-bass rumble, but then quickly gets out of the way with a fairly quick decay and without intruding into the midrange. Bass does have some texture, but those looking for a healthy bottom end should look elsewhere as the IE600 bass skews more towards clean & punchy.


Comparisons to the IE300 & IE900
The IE300 is more 'consumer-friendly' with an entry-level sound. Treble is sharper & thinner while mids are more recessed & there is some mid-bass bloat. The IE600 is a technical upgrade in all directions from the IE300 offering a more balanced presentation.

The IE900 has more resolving power with a deeper V-shaped sound with higher highs & lower lows. The IE900 does have the taller stage with added resolution & air. Bass digs much deeper and there is more of it to satisfy those craving "moar" bass. With the added resolution does come some caveats - highs can come off as strident at times & the added bass presence can sometimes threaten to overshadow the rest of the frequencies. The IE600 tones down the edges with a more relaxed treble. Bass is still represented well, albeit with a cleaner attack & quicker roll-off and mids are more in line with the other frequencies to give the IEM a more balanced sound, while mids on the IE900 are more recessed in relation to the rest of the FR. The IE900 though will shine on larger performances with its wider soundstage and greater separation. Shortly before the release of the IE600 Sennheiser announced a price increase on the IE900 (from $1299.95 to $1499.95) due to the worldwide supply chain issues; thankfully they were able to keep the price of the IE600 at $699 making it a better value proposition.





Model designations on the inside shell - IE300 & IE600 are stamped (on plastic & zirconium shell respectively), IE900 has an etched feel.



Conclusion
Middle child syndrome* is the belief that middle children are excluded, ignored or even outright neglected because of their birth order. The IE600 has dual resonators as opposed to the three in the IE900 & doesn't include the additional 2.5mm cable. However, it utilizes a patented 3D printing process to craft the ZR01 amorphous zirconium housing, the same material used in the drilling head of the NASA Mars Rover. Additionally, it seems more DAP manufacturers are adopting the 4.4mm termination anyway so the loss of the 2.5mm cable isn't a big one.
The IE600 sits in between the IE300 & IE900 in regards to pricing as well as specs. Sound-wise & resolution-wise it slots in between the two as a middle ground, although the jump from the entry level IE300 to the mid-priced IE600 is more marked than the difference between the IE600 and the flagship IE900. The balanced & natural tonality should work with most music genres. Coupled with the solid & compact build as well as their efficiency means the IE600 would be a great daily driver.






Test Tracks (16-bit & 24-bit FLAC) - including, but not limited to
Agnes Obel
Atticus Ross - Panoramic
Augustana - Boston (Live), Fire (Live)
Bill Conti - The Thomas Crown Affair
Billie Eilish - Bad Guy, Bury A Friend, Getting Older
Bloc Party - Banquet, Mercury (Herve Remix), Signs, Signs (Armand Van Helden Remix)
Claire - Broken Promised Land
Daft Punk - Tron Legacy Soundtrack
Gang of Youths - Achilles Come Down
Hozier - Arsonist's Lullaby, Take Me To Church
Ingrid Andress - More Hearts Than Mine
Jhene Aiko - Bed Peace, The Worst
John Legend - Let's Get Lifted
John Murphy - Sunshine Soundtrack
Jonsi - Go Do, Tornado
Kanye West - Black Skinhead, Jesus Walks, Mercy, No Church In The Wild
Kings Of Leon - Waste A Moment
Linkin Park
London Grammar - Hey Now, Metal & Dust
Lorde - Bravado, Ribs
Miike Snow - Cult Logic, Silvia
New Order - Bizarre Love Triangle, Blue Monday, Ceremony, Temptation
Nicholas Britell - Succession Season One
Nina Simone - Feeling Good, Sinnerman
Raye Zaragoza - Crazy Eyes
Regina Spector
Sky Barbarick - Paper Legs
The Chemical Brothers - Wide Open
The Cinematic Orchestra - Arrival of the Birds
The Lumineers - Cleopatra, Ophelia
The Naked And Famous
The Sounds - Goodnight Freddy
The xx
Thirty Seconds to Mars
Wael Elhalaby - Smooth Sailing
Yiruma
Yo-Yo Ma - Bach Cello Suites

*I know the IE600 is technically the third to be released in the lineup, but it works for my review.

Disclaimer: This is a biased preference. Please give the unit a test run before making a purchase.

The Sennheiser Single Driver IEM has a V-shaped sound signature. The driver is housed in amorphous metal that was 3D printed. You get three pairs of silicone and foam ear tips (S, M, and L) in the box. You get two cables, one with a 3.5mm termination and one with a 4.4mm termination.

I heard enough sub-bass rumble with a decent thump, and the bass is warm but not boomy. The highs are clean with decent air and at least sibilant, but for those who are treble sensitive, they can be sparkly or harsh on some tracks.

The decay of the bass is clean and does not bleed into the mids. If you like V-shaped tunes, the mids are laid back and not in your face, which may be beneficial for long music sessions. The holographic sound stage of the IE600 impressed me greatly.

The review is based on Qobuz/AM as a source via laptop onto iFi's Gryphon (using GTO filter) at +61db volume. Please keep in mind that I did not use stock tips, but rather the AZLA Sedna Light ear tips.

Tracks used for this review:
1. 4ware by Deadmau5
2. Rockstar by Post Malone
3. Thriller by Michael Jackson
4. 295 by Sidhu Moose Wala
5. Usure Poyene by A.R. Rahman & Karthik
6. Pathala Pathala by Kamal Haasan & Anirudh Ravichander

What could have been better?
1. The cable quality, which is prone to impressions even with minimal force applied for long periods of time.
2. The stock tips, at least for me, were not a good fit. Although the IE600 sits comfortably and does not feel heavy during extended sessions.

Sennheiser has been in the audio business for decades now. Over the years, Sennheiser has released several famous headphones that are still going on in the industry as legendary headphones. Do I really need to mention the names of the HD600 series of legendary headphones here? Sennheiser also happens to have a rich collection of audiophile-grade in-ear monitors that has again gained a good rep among audiophiles from all around the globe. For so many years, Sennheiser has gained this rep based on its successful tunings and excellently designed products. When I talk about the premium audiophile-grade IEMs by Sennheiser, I instantly start to name IE800 and the IE800s, because I have heard so many good things about these from my experienced audiophile friends. Personally, I never got a chance to audition for the IE900 or the IE900. In recent times, Sennheiser introduced some new products into the “IE” series of in-ear monitors, the IE300, the IE900, and the recently launched IE600. As one might have guessed from their numbers, the IE300 is the entry-level set, the IE900 is the flagship, and the latest IE600 is the bridge between both the IE300 and the IE900. IE600 which was released a few months back into the international market got released in my country just a few days back. With waves of positive feedback from friends and other audio lovers, I got so excited to try the IE600 upon its launch. Luckily, I got a chance to get a hold of a unit, so let’s begin our review on the IE600 without wasting any more time.


A Short Disclaimer Before I Begin on the Unboxing part:-

I got this unit from Sennheiser India for the purpose of this review. The unit was with me for about 10-12 days, during which I gave the pair some of my favorite tracks to test it out. Wanna know more about the IE600? Head over here to the IE600 product page on their official website.

About the IE600:-

IE600 is a single dynamic driver IEM designed with a 7mm TrueResponse dynamic driver on each side. The ear shells are crafted using high-precision 3D printing technology built with Zirconium Alloy material. The pair is priced at about 700-800$ in the international market and about 60,000 Indian Rupees in our local Indian market. Won’t waste any more time here and we will begin on the Unboxing part.

Unboxing The IE600:-

Sennheiser follows the same design theme for the retail package of its audiophile-grade products. It includes a greyish box with the Sennheiser logo and an image of the product on the front. The contents of the package are in a black cardboard box that opens in a sliding manner. Our stunning IE600 ear cavities are kept on the very first foam layer, below it we have some documentation(user guide, warranty card, authenticity certificate, etc.). At the bottom of the package, we have the accessories that include two cables, a cable clip, three sets of silicone ear tips, three sets of foam ear tips, and a cleaning tool. Package contents are again identical to the IE300 and the IE900 only difference being the no. of cables in the package. IE300 came with a 3.5mm cable, and IE900 came with three cables including a 2.5mm, a 3.5mm, and a 4.4mm cable. IE600 comes with two cables, a single-ended 3.5mm and another balanced 4.4mm cable. Well, that’s about the package and the contents of the IE600, let’s move on to the Design and Build quality for the set.


Package Contents:-

>IE600 earphones.

>Two cables(3.5mm+4.4mm).

>Zipper carry case.

>Three sets of silicone ear tips.

>Three sets of foam ear tips.

>User guide.

>Authenticity certificate.

>Cleaning tool.

Design & Build Quality:-

At a first glance, one might find the IE600 to be identical to the IE300 and the IE900 in terms of shape, what makes it different is its manufacturing technique and material. Sennheiser has hand-crafted the ear cavities for IE600 using high-precision 3D printing technology. The brand has used high-quality AMLOY ZR01 alloy for the cavities which is said to have triple the hardness and strength of high-quality steel. The shells look amazing with a nicely textured finish. Even though they are metallic, they are lightweight and give no issues in achieving a comfortable fit. With their compact form factor, the shells hide nicely into my ears.


The cables are the same as what we have with the IE300 and the IE900. They still have a little bit of microphonic issues and have a sticky outer covering. Since the pair uses proprietary MMCX connectors, the pair won’t be compatible with standard MMCX cables in the market. The cables could have been improved, kind of my only concern with the set.

How Do These Babies Fit? Fit & Isolation:-

They fit perfectly, I mean just nicely, and show me no issues. I use medium-sized stock silicone ear tips, and the isolation is just perfect. With such perfect isolation, I can easily enjoy my music at low volumes. Since the pair has a compact form factor, the shells disappear into the ears. It’s the memory hooks on the cable that reminds us we are wearing something. Fit & Isolation-wise, IE600 is perfect for my medium-sized-ears, you can have a look at the image below.


Let’s Power The IE600(Power Requirements):-

IE600 doesn’t take a lot of power but it surely benefits from a decent enough source. For my testing, I used the IE600 with my Redmi Note 10 Pro smartphone(3.5mm output), Apple iPad Air with Shanling UA3 portable DAC/AMP, the HiBy R5 Gen 2 Music Player, and the Shanling M7 Music Player. While the set sounds good with the Smartphone itself, it benefits from the high-res decoding through the UA3. Class A amplification of R5 Gen 2 makes it sound fuller and lively. M7 pairing is the near-perfect I have found with the set so far, with good energetic sound with a pitch-black noise-free background.

At the end about the power requirements, I would say IE600 can run easily off a decent enough source, even a Portable USB DAC/AMP is good enough for it. If you have a mid-fi level or high-tier DAP or DAC/AMP, that would just be the icing on the cake.

Let’s Find Out How Does It Sound(Sound Impressions):-

Well, well, well, Sennheiser has done a great job with the single 7mm micro dynamic driver on the IE600. The pair has a perfectly balanced V-shaped sound profile where nothing feels over-emphasized or overpowering the other. The pair itself has a refined sound signature. It sounds clear, crisp, and clean, clean especially with my M7. In terms of overall presentation, IE600 has a tightly controlled lower end, slightly recessed midrange, and a detailed, lively treble region. The 7mm micro-dynamic does wonders here with its presentation. Talking about the tonality of IE600, I would say the pair has neutral with a hint of warmth. With my Shanling M7, the pair shows great resolution, vocals despite being recessed have a rich presentation. I am a craver for good vocals, and the set doesn’t disappoint for both male and female vocals. Let’s discuss the sound frequency wise now.

Lower-End, Some Groovy Bass:-

As I stated earlier, the IE600 has a punchy, tight lower-end presentation. The pair produces deep-going sub-bass rumble with decent punches in the mid-bass region. Lower-end shows a refined presentation, the bass doesn’t sound boomy or muddy by any means. It shows good character for genres like Hip-Hop, EDM, and my regional Bollywood music.

Midrange, Rich Vocals, Detailed Instruments:-

Even though the Midrange has a recessed presentation, but shows good clarity and resolution for both vocals and instruments. There is no congestion or shoutiness in the midrange, IE600 shows good air and separation on a spacious soundstage. Vocals, both male and female sound simply wonderful. They don’t get harsh, and maintain their smooth texture even at loud volumes. The best part here is that the pair doesn’t lose its resolution even when pushed at high volumes. Vocals and instruments don’t go shouty or berserk at loud volumes, you can enjoy them easily.

Treble, Lively, Detailed, Inoffensive:-

IE600 produces a smooth and soft treble region. It doesn’t sound sharp or bright, in fact, has an inoffensive tuning for the high frequencies. Sennheiser IE600 shows good extensions and retrieves good details from the treble region. Instruments such as Electric Guitars, Violins, maintain good resolution in their high frequencies. High notes of vocals don’t have a sharp character to them, I would say one can easily enjoy the pair without worrying much about listening fatigue or sibilance from the set.

Soundstage, Imaging, Resolution:-

Well, Do I still have to tell you that the pair has excellent resolution hehe. Man the IE600 excels in clarity and resolution, that’s among the list of things I like about the set. Soundstage-wise, the pair shows good width and depth on the stage. I would say depth especially with my Shanling M7 is pretty good with the pair. Everything on the stage is presented in a layered manner. Imaging wise it's good, one can pinpoint different instruments and determine the position of the vocalist easily on the stage. Sennheiser IE600 has a dynamic presentation, it just sounds lively and full of energy.

Sennheiser IE600 Vs Meze Advar:-

I am not comparing the IE600 with the IE300 or the IE900 because I tried them long back and it won’t be good to comment on them without recent experience. But, I got lucky when I got a chance to listen to the Meze Advar at a headphone zone event in my city that happened just a few weeks back. Both the IEMs have a single dynamic driver configuration and are priced the same in my country(60,000 Indian Rupees). Please note that I didn’t give Advar much time(about 30-45 minutes but was able to make a few notes) so these impressions are from my notes.

>IE600 has a more neutral presentation. Advar has a warmer tonality in comparison.

>Advar has a huge soundstage, it just sounds grande. IE600 doesn’t sound congested or anything, it also has a wide soundstage, Advar just sounds bigger in comparison.

>Fit-wise both the IEMs are identical.

>Advar has a more relaxing sound presentation while IE600 sounds more energetic and more lively.

I would say both the Advar and the IE600 complement each other with their sound signatures. Personally, I enjoyed both of them, but at the time I was looking for a neutral-sounding set, the IE600 suited more to my requirements and I ended up buying a set of the same.

Let’s Conclude The Review, Final Words:-

What’s better to say here is that after trying the IE600, I instantly made up my mind to buy this set. I got a unit already, the review sample was returned a few days back, all the images in this blog are from my personal unit. I just found the IE600 to be a perfect single dynamic driver IEM, at least for me. Surely it has a few flaws of its own, like the stock cable, also not everyone prefers a V-shaped profile, but after spending over 100 hours with the set, I can assure you guys that the IE600 has a perfectly balanced, well-done V-shaped tuning. It engages the listener with its charming sound, something that I personally find to be complementing different genres of music. I have tried everything from acoustic/classical slow music to fast EDM profiles, IE600 hits the perfect spot with all of them.

If you guys like my review, please leave me a like, and do follow my profile for more reviews. For any questions or queries, feel free to ask me in the comments section below.

Disclaimer: This unit was sent directly to me by Sennheiser and it is part of two tours arranged by themselves, one in Europe and one in the U.S. This unit will be sent back to Sennheiser after my assessment to be sanitized and sent to the next person in line. Sennheiser asked for nothing else but a full review and opinions, without giving any incentives or influence over them, so as always, what you are about to read are my own thoughts and opinions. Thanks once again to the Sennheiser team for giving me this opportunity.

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Sennheiser needs no introduction. The German based company has proven over the test of time why they are considered one of the top dogs at the game - their full-size headphones are some of the most recommended and acclaimed pairs all over the internet (I still haven’t heard any, so shame on you nymz, what a joke).

Last year, during the summer, the world skipped a beat, as two single-DD IEMs were announced: the now (in)famous IE300 and IE900. Sennheiser’s plan was simple: take a shot at the fabled tale of great top-tier DDs with the 900, while giving the crowd a more budget approach to taste it.

To my sadness, I never had a chance to try any of these, as only the IE900 appealed to me, but the hefty price tag did not, as it’s still $1500 for a single dynamic driver IEM. Those who had a chance to try them, mainly complained about the relatively recessed pinna gain, affecting the mid-range of the replay, while others grabbed their tinfoil hats and started speculating how there would probably be another release between the 300 and the 900 later down the road. Half a year later, the tinfoil hats were thrown into the air like students after graduation, and there was the announcement.

The Sennheiser IE600 is a 7mm single dynamic driver IEM kicking in at 700 USD, according to the official website. Following the same form factor as the other 2 predecessors and with a 3D printed shell made of a special metal, the footprint is small and the weight is marginal.

Is it the fabled high-end DD everyone is looking for? Let’s find out together!

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• 3.5mm (single ended) MMCX cable;
• 4.4mm (balanced) MMCX cable;
• 3 pairs of silicone tips with tuning foams inside;
• 3 pairs of foam tips with tuning foams inside;
• Carrying pouch;
• Manuals and warranty;
• Cleaning tool;
• Shirt clip.

Before we delve into what really matters, I would just like to touch on some important non-sound aspects.

First one would be the fit. At first I had it and then I guessed it was related to the small form factor, but then I quickly realized it wasn’t - the fit on these is heavily tip dependent.

With stock tips, I was having problems even just having a seal. I panicked at first, as these tips have tuning foams inside it - a last line touch of tuning that Sennheiser uses to achieve the intended sound.
As you might guess, this was a major concern to me because, if I am having fit and seal problems when I move around and I need to change tips, that will affect the tuning, right?

Long story short, not by much (please see the graph below, in the sound section regarding this difference). In fact, after tip rolling and ending up using Final E (large size) tips, getting a better seal opened up the sound even more, giving me a sense of a more controlled mids and upper treble, with more impactful bass, and as of that, the following impressions are not based on stock tips but using Final E tips. If you end up buying this, beware, as you might need to tip roll a lot.

As for isolation, I would consider them on the average or slightly above average, depending on the size of your ears. The small form factor is brilliant for people with smaller ears or canals, as they fit really deep and not shallow. For people with larger ears, you might have more problems regarding fit or isolation.

Another word must be thrown into the pot, mentioning the stock cable. I must confess I did not try any other aftermarket cables with the IE600, and all these impressions were done stock.
Both provided cables are the same, only the termination changes and they connect to the monitors using MMCX standard connectors. The important thing to note about the stock cables is that they include moldable earhooks, which is unusual and only the second time I have used it (first one was Sony EX800ST). Keep in mind these are meant to be adjusted/tailored to your own ears, so play around with them, as I feel they are very important to help with the fit and comfort, as you can shape them how you please and together with the MMCX 360º rotation, they should fit your ears like they need to.

With the stock cable and the carrying pouch (that I love by the way, as it is simple and small), the IE600 turns into an ultimate grab and go IEM, as you just slide it in your pocket.

Given all the above, I feel I need to sprinkle all the gold dust right now and say that the Sennheiser IE600 is one of the most comfortable IEMs I have used, despite not being the best fit ever, and that plays a big role in my daily life as I am always using something on my ears, but keep in mind your mileage may vary, as every ears are different.
The nitpick I will leave is regarding MMCX connectors, as I am a public and vocal disliker of the system, but in this case it works for the best. My word to anyone using MMCX connectors is to choose a cable and stick with it, as these connectors start to get loose with time and/or if you cable roll a lot.

As for driveability, I would say they are on the average side of things. They require some power but most used sources in the market should suffice, including the usual dongles. Bluetooth DAC/AMPs like Qudelix5k shall suffice very well, as I’ve tested that as well one of the times I was shopping for groceries.

I am a source enthusiast, so what I am about to say should be taken with a grain of salt and keeping in mind YMMV: I think the Sennheiser IE600 scales a little bit with power and pairs better with slightly warmer or more analog sources.
I found the best results to be achieved with Class-A amps (Singxer SA-1, Hiby R5 Gen2), the more analog warmer sources like the iFi xDSD Gryphon or the more neutral and technical (Cayin N3Pro on Solid State). I also did extensive tests with the Topping E30+L30 stack, and it worked great as well, giving an edge on the treble and detail.

A last word on Gryphon, as I really enjoy the combo with the IE600: for bassheads you can just turn on the magical XbassII button to help you with that. I would recommend also using the presence switch to give both bass and upper mids, as it balances out the natural V-shape of the monitor. Xspace also works wonders for the presentation, although it will leave out the more natural or intimate feel of it.

Enough rambling, let’s talk sound, shall we?

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Right out of the gates, I would summarize the Sennheiser tastefully done V-Shape. Just by looking at its graph, it’s pretty obvious what was the objective traced for the monitors: A prominent bass and upper treble elevation, with just enough pinna gain for the mids to not feel that much recessed. Depending on each's own personal neutrality, some folks might even consider this more of a U-Shape than a V-Shaped IEM.

On my first impressions of this set, I shook things a little and started by the higher frequencies, but now I will serve you the course meal first, the start of the show and the reason most will fall in love with it - the bass.

In a word? Gooooooood. Tracks like “Why So Serious?” prove just that, just like the treble, bass extension is one of the show stoppers. At around 3 minutes and 26 seconds, the world will just rumble at your feet - funny fact, it happened to me while picking groceries.

Another proof of the lower end is the musical classic Angel by Massive Attack. This track’s intro also helps to explain how the tuning has emphasis on the sub-bass over the mid counterpart, by showing its rumble and going down low.

While listening to “Playing God” by Polyphia, all enphasized aspects come alive. The level of treble presence and detail bring a new level of micro-details to the song, while the bass drop around the 28 seconds just feels authoritative. Both are a bit on the overemphasized territory in comparison to the mid-range, but still leave out a clinical taste on your lips, without bleeds whatsoever.

Despite the mountain of elevation in the low end, the mid-bass is impactful but clean. It isn’t really a real Slam Jam party as some will expect from the graph, but it pushes some air together with the elevation, and you can bet you will feel it, while not overshadowing the track, at least not as much as the treble or the sub-bass. The pedal played by Elise Trouw on her live loop of “How To Get What You Want” is a nice proof of that, and correctly balanced with her voice, while still showing its authority.

Speaking of vocals, let’s quickly transition into the mid-range, or as expected, the weakest link. I will be honest, I was expecting much worse mids, and way more recessed. They are a bit recessed, but still just south of neutral to my ears. I still find the need to increase the volume a bit as I am a mid-head and on very balanced tracks like the famous version of MTV Unplugged’s “Hotel California”, where Eagles performance needs a touch more mids in comparison to the treble sparkles and the monotonous bass punch. Despite not being as balanced, it was one of my favorite replays of the track so far, so touché.

Given the ultra transparency of this mid-range, pianos sound great and very detailed, just like Hania Rani - Glass can show us - all the wood sounds are there, and just right and well separated, without a blur.

Vocals are, in my opinion, the IE600’s weakest link, but despite not being anything to write home about, they are very far from bad. They are transparent, clinical and very detailed. I still sometimes miss my Softears RSV’s organic presentation, that just fits me better in this regard, but you can’t have the cake and eat it at the same time. Again, for those that prefer neutral mids or vocals, this won’t be a much of a problem, as the micro details and the cracking on voices are just on point - a good example of this would be the Sway version by Diana Krall, where you can feel hear all her lip touches or vocal textures.

What was less expected to me is the fact that the female vocals sound better than male do, having more bite but without ever going into the shout territory whatsoever (Adele - Oh My God and Lykke Li - Silent My Song). Michael Bublé’s performance on “Feeling Good” gives a slight feeling of something missing, maybe some weight and presence that is, again, south of neutral.

If we keep climbing into the frequency range, we finally reach the other headline: the treble.

I think I can’t mention IE600’s treble frequencies without mentioning some of its technicalities: The amount of clarity and sheer detail you get thrown at, for a single DD, it’s impactful and deserves respect. Sennheiser did it and IE600 is the most technical single DD I have experienced to date, and I knew it in the first 30 seconds of my take.It’s actually pretty obvious how they are achieving this - besides all the work inside the shell and the driver itself, - if you look at the mid to upper treble region.

I’ve been extra kinda so time to cut the candy talk and rip another band-aid: These will be too hot for some people and/or music genres.

As an upper mids/lower treble sensitive person and fond of darker sets, the fact of me liking this level of elevation in the treble region surprised even myself. After further looking in the FR graph above, I would attribute this to the dip from the upper mids into the lower treble, a region where it makes or breaks an IEM for me, and holy moly did they get it right.

Cymbal strikes and electric guitars still sound great and natural, despite the dip. Lust For Life by Iggy Pop or the Larnel Lewis’s drum solo on Change Your Mind prove just that, along with Jason Richardson -Titan that also shows this contrast on more busy passages.

The boosted region above 8k hertz, it’s tiring for long sessions, and the first thing that came to my mind was the UM Mest brothers, who instantly overloaded me with too much detail, which I appreciate, just not the usual hours I listen to music everyday. Despite this fact, I respect the hustle, as it was cleverly done in my opinion.

Everywhere by Fleetwood Mac shuffled and here I am, mesmerized by how the intro of this song could describe this set’s upper treble: a beautiful bunch of stardust flying around, that can be too much for some, but beautiful nonetheless.



Sennheiser quality is undeniable, but let’s be realistic here, no one will be paying IE600 price just for tuning itself, as I’m still a preacher that tuning is free.

So, how are the technicalities of the set? In sum, a fallacy of composition - The whole comes out as great, as some of the weakest characteristics get blended in by the others, resulting in a better outcome.

Time to rip the band aid off, once again: the stage and imaging. Soundstage is size is modest and in some tracks it may be too close to your head or intimate, showing that it could use more depth and even width.
The stage height (Agnes Obel - Curse) is above average, but could still use a bit more extension, placing it well above the pack. Following the trend, its imaging (Yosi Horikawa - Crossing), sounds great on positional queues, despite not always being able to perfectly do the center imaging when compared to top dog’s like the 64A Trió.
The stage’s holographic presentation kicks in and is very well done, precise to be exact, when the track demands it (Yosi Horikawa - Bubbles), which is something I really value.

So how do these presentation flaws get masked, as mentioned above? For starters, the sheer detail is excellent, giving you a sense of micro and macro queues everywhere. Following the line, comes the dynamics of the driver, which are clearly up there with a fast tight response and sharp transients.

To close the winning formula, comes its timbre, something that I’ve been taking into consideration more and more nowadays with the instrumental part of my library, that despite not being the best in class, is up there, despite all the treble elevation that sometimes masks it or gives a metallic shrill on the brass instruments notes decay tail. In all, I would say the attack and the decay are pretty much in sync, neither too fast nor too slow (David Carroll - Hell’s Bells).

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As part of the Sennheiser tour, the reviewers were kindly asked to share some tracks that highlight the IE600, which I am always glad to oblige - always remember that music is the reason why we do all of this, not the gear. Instead of just dumping a bunch of electronic songs, I tried to fit some different genres in, to cover more angles and let people make more educated decisions. I will also leave some albums I listened to fully and I think the Sennheiser set did a great replay of.

• O’Flynn - Tyrion
• Jay Cosmic - The Tunnel
• Hans Zimmer - Why So Serious?
• Hyper - Spoiled
• DARKSIDE - A1
• Rameses B - Sonder
• Vanilla - Azure
• State Azure - Mirror Infinite
• Jungle - The Heat (Joy Orbison Remix)
• Marco Carola - Play It Loud!
• Trentemoller - Chameleon
• Sawano - aLIEz
• Ten Walls - Walking with Elephants
• Chris Lake - Free Your Body
• The Prodigy - Thunder
• Unlike Pluto - Everything Black
• Flume - Insane
• EVERGLOW - DUN DUN
• Billie Eilish - Oxytocin
• Dnmo - Broken
• Tyler the Creator - EARFQUAKE

• TiMO ODV - Origins (EP) (Tidal)
• Moderat - Moderat (Tidal)
• Kölsch - 1977 (Tidal)
• Paul Kalkbrenner - Parts of Life (Tidal)
• The Blaze - Territory (Tidal)
• Armin Van Buuren - Imagine (Tidal)
• Worakls - Orchestra (Tidal)
• Hans Zimmer - Dune (Tidal)
• Kindness - House (Tidal)
• Massive Attack - Mezzanine (Tidal)
• Ludwig Goransson - The Mandalorian: Chapter 1 (Tidal)

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I will now compare directly and talk about how I expected this set to rival my other single DDs like the Dark Magician and Zen Pro but (spoiler alert), I came to the conclusion they are all different sizes of the same tool, with the application and strong suits being library dependent.
I decided to highlight their worst and best features as some people who are considering one of them, will maybe also consider the other ones or they wanna compliment their DD collection.


Sennheiser IE600

IE600 has the worst fit of the three with average isolation, being very comfortable nonetheless due to weight and shell material/shape. It needs the most power/volume to achieve clean and audible mids in comparison. The accessories are very good and a great package overall. Stock cable is fine, but earhooks might be a deal breaker for some. It is priced in the middle of the other two and it’s the lightest of the three.

DUNU Zen Pro

Zen Pro is the most expensive IEM of this comparison, too close to the kilobuck region ($900). Is by far the easiest to drive, which also translates into a problem as it is very/too sensitive, hissing on most powerful sources of the market. Between the three it has, hands down, the best accessories, build quality and fit. Due to its semi-open back design, it also has the worst isolation of the pack. Being an all metal shell, Zen Pro is also the heaviest.

MiM Dark Magician

The DM is by far the cheapest, at around $600. It is a DIY IEM and the production was limited and even hard to get your hands on one. Nowadays, it got discontinued and you can no longer find it, as it got replaced by a new version that doesn’t sound or graph the same. Due to this, it has the worst accessories (only comes inside a circular metal box with some tips). Stock cable is good and looks great, but the earhooks need some slight adjustment for the fit. It has by far the best isolation when compared to the two IEMs above. Comfort is great and they are very light weight, almost like a father, for something that is made of metal.


All the comparisions you are about to read were done using the same source, the same plug (4.4mm balanced) and one of my test playlists (Tidal). I decided to add the following spider graph to be better visualized:
Sennheiser IE600

The IE600 has the most prominent bass and treble, which makes it the only V-Shape of this shootout. If you are looking for the most “fun” or energetic of the three, this is it. Nothing in this life is for free, as that much energy will come out as the most fatiguing of the pack - I would describe it as the one of the shorter sessions, best suited for electronic music.
Despite being the only one with recessed mids, this is just slight, and the upper mids/lower treble is very well done, on par with the Zen Pro, but coming out with the worst vocal presentation of the shootout. Stage size is the weakest point, as seen above in this review, but the imaging is good and it’s the most resolving IEM in this single dynamic comparison, giving a high sense of macro details and clarity, having the best extension on both poles.


DUNU Zen Pro

The Zen Pro is the instrumental beast. Paired with a balanced tuning, its timbre, driver speed and dynamics turn it into a technical beast. I would consider it a neutral with a slight bass boost and let me tell you, what a bass. It is the best bass quality and texture of the pack, together with a great sense of impact and its speed, putting it ahead of the others for people who prefer these characteristics.
One of the things that I immediately noticed was the sense of separation and layering it provides, but it lacks stage depth, despite having the best imaging of the three. The rest of the stage is above average, slightly holographic, and all this pretty much thanks to its open back design that comes out as a con for outdoor usage.
The micro details are good and have some sense of clarity, but not everything is all sun and butterflies, as the tuning is rolled off in both spectrums, and it’s slightly noticeable - despite not affecting my library as much. Another point against and that needs to be noted is that the upper regions timbre can get slightly off, especially with ultra bright sources, giving a sense of metallic taste. In my experience, it really shines with more analog sources like the Cayin RU-6 R2R dongle.
I would consider it best suited for instrumental/orchestral/jazz/classical libraries. It can get physical fatiguing after some hours of usage due to its weight and I would consider it good for medium sessions.


MiM Dark Magician

The DM has the most balanced tuning of the three - it is the real smooth operator. You can throw what you want to it, it will change like a chameleon and replay accordingly. Given its isolation and being less fatiguing than the others, I consider it can be used for ultra extensive listening sessions, for most libraries and anywhere.
Despite the semi-flat graph, don’t let it fool you, everything will show up when it needs to. The bass is the weakest of the 3 in terms of dynamics and texture, but it has very nice micro details all across the spectrum. Another point against the DM is that the imaging is slightly weaker than the other two.
Now, where it really shines is on stage presentation, containing the biggest and most holographic of the three, and having the best, or at least on pair with the Zen Pro, left/right pans.
Despite the good micro details, the overall clarity is very good but falls behind the other two, making it the least resolving one of this shootout. This fact is pretty much attributed to having the least amount of treble, which comes out as way less fatiguing and the best volume scaling by a mile.
The mids are borderline perfect and a true masterclass, making it the best vocal replays of the three. The frequency extension falls a hair shorter than the IE600, but above the Zen Pro.



I decided to add this chapter, as a last minute call, as I’ve read somewhere people complaining about reviews only comparing IEMs on the same bracket. This got me thinking and I decided to add a very short comment on how the Sennheiser IE600 compares to cheaper competitors in the single DD world. As we all know, the diminishing returns are pretty real so we will keep an eye on that.

Tripowin Olina (double stock filter)

My default single DD recommendation had to be included. For $100, Olina has been a tough bone to chew on.
While Olina features a Harman tuning, compared to the IE600 it comes out as less energetic. This also translates into a better midrange presentation by the Tripowin offer, paired with a better stage size and more holographic. The mid-bass is more prominent as well which makes it more impactful than Sennheiser’s.
Other than the points above, the IE600 is a much superior IEM in every front, especially on the technical side of things and the extensions. Despite costing 7 times more, it doesn’t not have 7 times the performance, but you are paying the premium for that last push.
If you are looking for an endgame V-shaped version of the Olina, the IE600 might be for you, as long as you are fine with the tradeoffs.


Dunu VERNUS (Reference Nozzle)

VERNUS, being a special and limited edition of the Falcon Pro, comes out as a neutral with a warm tilt, all across the lower frequencies. Opposite from the Olina, the biggest difference is in the bass, where the IE600 blows up the barrel and the VERNUS is shy. Combining that low elevation with a bigger elevation in the treble region, they feel like opposites, and filling different genres/libraries.
Same as Olina, the price difference won’t show the performance difference. However, if you feel you love VERNUS but want that XBass button on the go with better techs, the Sennheiser IE600 will suit you.


Tanchjim Hana 2021

I don’t have the Hana with me, so this will be a “from memory” thing, so take it with a giant grain of salt. If you really enjoy Hana’s signature, that mild V-shape, and want a technical upgrade, I feel the Sennheiser IE600 is your call.

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I might paraphrase once again the above review, but I really feel I am now in position to say that IE600 is the most resolving single dynamic driver I have experienced to date, and for that, it already comes out as a winner.

Again, every set has its flaws and Sennheiser or not, this is no exception. I feel this set won't work with every ear and every preference, and some will find it tiring after long periods of time. This won’t be a mid-heavy set, and I found it to work much better with the electronic side of my library, like techno and house, than it did with the more relaxed tracks. It won’t have the most accurate replay of a song, due to its bass and treble boost, but it sure will add a lot of fun to the replay.

To quickly answer the question I will be asked the most after reading this: Yes, I think IE600 is worth the price when compared to other sets in the market, for my tastes and library. Now, if spending hundreds on a single DD IEM is worth it, that’s up for you to decide.

If you are looking for a higher-end single DD, I hope this review helped you have a clearer view of which one to get. As long as you make an educated decision, I don’t think you can go wrong with this set.

I am very happy to recommend the Sennheiser IE600 to anyone that is looking for a fun and energetic single dynamic, especially a V-Shaped one that can also bring the resolving power to the table and challenge other types of driver setups.

As for me, I can’t wait for the future releases of single DDs and especially from Sennheiser. Good job!


Value Rating: 4.5 out of 5. Personal ranking: 8,7 out of 10.

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Thanks for reading!

Intro and disclaimer

I have been a Sennheiser fan since I was in my early teens when I started to get into this hobby. I remember seeing the HD600 in a store and hoping that one I would own one. I owned the HD600 and many more sennheiser headphones. I’ve heard even more on top of that including the original Orpheus.

I was excited to learn that I would be the first stop on the IE600 tour. I had heard a little about it but not much. I was very eager to give them a listen.

Sennheiser sent me the IE600 as part of the review tour in exchange for my review. At no point did Sennheiser influence my decision. My thoughts are my own.

Gear Used

Fiio M17
Empire Ears Valkaryie Custom
Sennheiser IE600
AZLA SednaEarfit Crystal 2 Tips

Packaging/Unboxing








Sennheiser has really never been known for their packaging but that’s fine with me. It’s there to protect the product before it reaches the custom and more often than not lands in a closet or the trash. The IE600 packaging is probably the most elaborate Sennheiser packaging I’ve seen but it just works. You open a quality feeling box where the IE600 is prominently displayed in foam. Under that is a certificate of authenticity which is stamped with the date of the final QA as well as the inspectors initials. Simple but a nice touch. Under that, you have a foam insert that holds a cleaning tool, instruction manual, case, tips as well as a 3.5 and 4.4 cable.


Accessories

The IE600 comes with a pretty wide variety of accessories. There are three foam tips, three silicone tips, cable clip, cleaning tool as well as two cables.

The cables comes in 3.5 and 4.4. They look very basic but the more I used the IE600 the more i liked them. I never had any tangles and there were never any kinks in the wire. It’s also really nice to have the 4.4 cable.

The tips are pretty standard but feel of very high quality. I found that I achieved a really good fit with the largest silicone tips. They sat more on top of my ear canal versus going in. It was very comfortable. My ears are a but strange and I ended up finding the best fit and comfort to be with the AZLA SednaEarfit Crystal 2. I think for most ears, the stock tips will work fine.


Build

Solid! The shells of the IE600 are all metal and feel very durable yet light. They are just the right shape for my ears and I think will be a great fit for most. I wore these for hours at a time with zero ear fatigue or discomfort.

I have the best luck with IEMs that fit within the concha and are held in the ear by the anti helix. The IE600 does it perfectly. It keeps the tip firmly in the ear.


Overall sound signature

My first time I listened to the IE600 my jaw literally dropped. Powerful bass and clarity with an extremely cohesive signature. I thought… i didn’t know these were hybrids! I looked it up and confirmed that they were in fact a single dynamic driver. I knew right away these were special.

I never heard any issues with portly recorded tracks. The IE600 always sounded good but scaled well with really well recorded music. I’ve heard a bunch of high end headphones that struggle with poor recordings. That is definitely not the case with these. Very happy with they flexibility


Bass

Just right for basically every track I threw at it. Never boomy or overpowering the mids. The control is amazing. These are very well tuned IEMs. It also reaches very deep. When needed, there is plenty of kick.


Mids

There is a slight dip in the mids especially with vocals but I never felt like I was missing something. Vocal forward tracks still sounded like they should. I did notice a bit of sibilance on a few tracks but it was fairly rare. Going to a slightly warmer source (M17 to Mojo) did cut it own a bit. It didn’t bother me at all but some people that are very sensitive to it should know about it.


Treble

The treble is fantastic. For me, they reached high enough to give a nice shimmer to high hats, fast attack on stringed instruments and amazing clarity. I think it's just north of neutral which is great for my taste in music and preferences.


Stage

I’m not great describing stage on headphones. I think the IE600 is average for an IEM with the sound more to the left and right versus in front of you. Instrument placement is very precise. No issues for me here.


Comparisons

Afterglow - Emancipator
IE600 - The first thing that strikes me is the insane deep rumble of the sub bass on this track. I really like this track for evaluating bass and the Sennheiser does not disappoint. I’d maybe like a little more kick but the low reach and control make up for the lack of quantity. Lots of detail with out harness in the treble. Very enjoyable with this track.
Valkyrie - At the beginning of this track the sound moves back and forth between the left and right channel. That back and forth is less noticeable on the Valkrie. Not sure why. Not an issue just an observation. There is more bass quality with a little more energy on mid bass with a little less control. Don’t get me wrong, I love the sound of the OG Valkyrie but you can definelty tell there are advantages to a really well tuned single driver. There Sennheiesr just comes across as having better clarity with the same level of treble but more natural.

Lindsey Stirling - Elements (Orchestral Version)
IE600 - Very open sounding with so much clarity. This track is really enjoyable with the Sennheiser.
Valkyrie - Right away I notice a little more warmth. Lindsey’s violin feel a bit more distant. Instrument placement is a little less precise. There is a little less energy and simmer in the treble. Still sound great but the IE600 seems to play a little better with this track. I still really like this track with the Empire Ears. It’s just a little more laid back of a signature.

Grateful Dead - Touch of Gray
IE600 - I’m really liking this track on the IE600. Nice punch sound with great clarity. Classic rock can sound a but thin but not with these. Very enjoyable.
Valkyrie - Again, a little more warmth. Still very enjoyable but the IE600 seems to excel with this track.

Angus and Julia Stone - Yellow Brick Road
IE600 - Great vocals. The clarity trend continues.
Valkyrie - The stage is a but more in front of versus around. The sound is less aggressive and smooth. Still very enjoyable.

Alison Krause - It Doesn’t Matter
IE600 - Great live feeling to this track. Very good clarity and great rumble on the bass. The attach on the guitar is really good and reminds my of over ears planars.
Valkyrie - A little smoother sound. Bass has a little more quality and mid bass presence. Both sound really good on this track. This track can have a bit of sibilance and both IEMs don’t hid this but it’s not offensive.

Eric Clapton - Old Love Unplugged
IE600 - There is a great live feeling on this track. The clarity gives you a sense of being a live performance.
Valkyrie - On this track, I like the Sennheiser better. It’s not bad by any stretch. The attack on the guitar is not as good. I think this is a track where you notice the downside of multiple drivers versus the single dynamic of IE600. The Valkyrie does not give the same feeling of the live open stage of this track like the Sennheiser does.

Conclusion
The IE600 is an outstanding on IEM on every level I can think of. Not picky with genres. Amazing clarity. Single driver coohisive signature. There is just so much to like. At it's price point, I really can't think of a better IEM. It challenges IEMs that cost double what they do. Sennheiser knocked it out of the park with these IEMs. Great job!

Update: I had these on loan for another review and realized I needed a pair. I bought a pair retail with my own funds. Highly recommended.

Introduction

The Sennheiser IE600 was loaned to me by their Greek distributor for local reviewing purposes but I have decided to share brief impressions at Headfi.

The IE600 is the new, single dynamic driver iem from Sennheiser which is positioned between the flagship IE900 and the entry level IE300.
The selling price is €700 and is available from all authorized retailers.



Technical highlights

Resilient AMLOY-ZR01 amorphous metal housing, 3D-printed in Germany.
Direct, neutral tuning with fast, accurate bass.
Select 7 mm TrueResponse transducers optimized to achieve the lowest possible distortion.
Exceptionally neutral sound thanks to dual resonator chambers D2CA.
Gold-plated Fidelity (+) MMCX connectors for reliable connections.
Choice of para-aramid reinforced cables (3.5 mm, 4.4 mm).
Adjustable ear hooks and choice of ear tip adapters.
Frequency response: 4 Hz – 46.5 kHz
0.06% THD (1 kHz, 94 dB)
Impedance: 18 ohms

Full technical breakdown is available here.



Build quality and appearance

The IE600 is made from zirconium alloy which is manufactured by Heraeus Amloy Technologies.
It has triple the hardness and flexural strength of high-performance steel. Shock-frozen during manufacturing, amorphous metals never have a chance to form a crystalline structure like conventional metals.
The result is a lustrous, satiny surface that is extraordinarily resistant against corrosion and scratches.
The IE 600 housing is fabricated using metal-powder-based 3D printing that can create any shape imaginable within tight tolerances. Chambers and channels form as part of this additive manufacturing process with no milling required.
However, cost does limit the potential applications of this new material. One of the only places you’ll find it — besides ultra-high-end products like the IE 600 — is in the drilling head of a NASA Mars Rover where extraordinary resilience in extreme conditions is required.



The appearance is the same as with the IE900 but instead of the shiny and polished surface this time the finish is more dull and less luxurious.
I slightly prefer the IE900 appearance but still this is a discrete and beautiful looking earphone that gets vanished into the ear.
Build quality and finish are excellent while the IE600 seems to be very durable and scratch resistant, much more than its elder brother.



Fit and isolation

The IE600 is featherweight and with very small size, it is a real "in ear monitor" and a nice contrast to the bulky multi driver earphones that are flooding the market.
The shells are tiny and as such they vanish inside the ear, offering a tight and ultra comfortable fit suitable for extended listening sessions without causing ear fatigue and excessive sweating.
If there is one issue worth mentioning is that due to the shorter length and diameter of the nozzle, the IE600 must be pushed deeper into the ear canal, so the user might need a larger size of eartips than the usual and the largest size of the provided ones might not be enough.
Tip selection is crucial regarding noise attenuation and bass response, the memory foam eartips worked better for me and after getting the right fit the IE600 proved to be very effective in blocking outside the environmental noise.



Cable and accessories

The IE600 features gold-plated MMCX(+) connectors that are recessed in the housing for greater stability and guidance.
This type of MMCX connector is slightly different from the normal and finding an aftermarket cable is not so easy.
Two para-aramid reinforced cables are included, unbalanced 3.5mm and balanced 4.4mm.
There is also a 2.5 mm cable that is sold separately and not included as it is with the IE900.
Flexible, adjustable ear hooks further enhance the long-lasting comfort.
I know that a lot of people were complaining about the IE900 cables but honestly I think that they are of good quality, quite flexible and with low microphonic noise so I wouldn't bother with aftermarket cables.



Two different styles of earbud tips — silicone and memory foam — are provided in three sizes to establish a comfortable seal in any ear.
A Premium carry case is also included along with a cable clip and a cleaning tool.



Listening impressions

As per usual practice I left the IE600 to burn for about 150 hours without monitoring the progress.
The listening tests were done with the FiiO M17, FiiO M11 Plus LTD and iBasso DX240 with the AMP8 MK2 module.



The overall tuning of the IE600 is utterly natural, not neutral and very balanced, it is pretty much one of the best tuned earphones that I have ever tested, almost perfect.
The sound is good, very good, musical, engaging, fun and enjoyable without venturing into tuning extremities.
This is a safe tuning that is suitable for all kinds of music, from electronic music to classical and jazz.
It is a likable presentation without any faults and most users will probably find it to their liking except the ones who prefer purposely mannered tunings.

The bass is just slightly boosted above the reference point with great extension to the lowest of the notes.
It never becomes too much and acoustic instruments like double basses and organ sound with the correct pitch while the IE600 is equally great with synthesized bass.
There is no bleeding whatsoever into the mids and the mid-bass is perfectly pitched without any unnecessary emphasis or coloring, at the same time the IE600 should be considered warm enough in a balanced manner.
The presentation is quite full but not so visceral and weighty yet at the same time it shouldn't be considered as lean, it sits somewhere in the middle.
Technical presentation is truly excellent, at least for the category.
The bass is tight, fast and well controlled with natural recovery and great layering while it is clear and resolving.
Dynamics are good and lifelike but the IE600 doesn't have the physical impact of other single dynamic driver earphones with larger drivers like the FiiO FD7.
Still the overall result is pretty satisfying and substantial both with natural percussion instruments and electronic tunes.

The mid range is, well, perfect, the tuning is wholly engaging, voices and instruments are rendered with the most convincing timbre with plenty of harmonic saturation.
The sound is weighty, full bodied and rounded with excellent presence and the most fine articulation, airy, soft and pleasant without any given harshness or edginess.
Natural sounding with just the needed amount of sweetness, warmth and wetness, the perfect combination of all the right ingredients that make for a highly addictive musical experience.
It is a pleasure to listen to all kinds of voices or vent instruments like solo oboe, clarinet or some blazing horns.
The IE600 was good with everything I tested but I thoroughly enjoyed it with Mozart's Gran Partita for twelve wind instruments and a double bass.



These are HD650 - like mids, the closest tuning to the all time classic but this time with augmented technical prowess, more clarity between the lines, airer and more defined presentation.
Old time users of the venerable HD650 are going to love the IE600 this is the first Sennheiser creation that should be considered as the true successor to it, although in an iem form factor.

Thus said, there is a mild sibilance, it is not that the IE600 is inducing it in an artificial way but it is highlighting it when it is present in the recording.
"T" consonant gets a little pronounced and "S" even more, especially when listening to choral works like the following recording.



Treble has a very safe tuning, smooth, controlled and absent of any alarming peaks.
At the same time the IE600 is pretty resolving, with good clarity, adequate extension and enough energy to sound lively and not dull or boring.
Again pleasing and natural to the ear, treble sensitive users are going to love it while it gets pretty satisfying and detailed to cater for the rest.
Only the treble loving crowd and detail junkies will not remain satisfied and they will probably seek for something more detailed, analytical and brighter than the IE600.

Soundstage is mildly wide and spacious but not so holographic or layered.
Positioning is very accurate, with nice separation between the instruments but the whole presentation is more into the head, intimate and rather shrunk than glorious and expanded.



Brief comparisons

The IEx00 family
(from memory)

The IE600 is the sweet spot between the IE300 (review) and the IE900 (review) regarding both the tuning and the technicalities.

The IE300 is the least technically capable of the three.
Not so resolving, with lesser clarity, bass is not so controlled and layered, not as tight and it gets more bloomy - bleeding while generally speaking it is not as refined and articulated as its brothers.
Bass on the IE300 is more pronounced, with a touch of mid-bass emphasis while the mids are considerably more recessed, not as natural sounding and engaging while treble gets a fair amount of boost, here and there, giving a brighter and sharper tuning.
The IE300 is fuller sounding with more meaty sound, more fun, but thicker and slower with less natural timbre, not as precise and sometimes a little bright - piercing.

On the other hand the IE900 is technically superior, everything is on a higher level, from bass control, to layering, articulation, extension, detail retrieval, imaging, far better clarity, well you name it and the IE900 does it better.
Better dynamic contrast, more impactful with a grander and more holographic soundstage, out of the head projection with laser like positioning and a much finer articulation, the IE900 is the undisputed High End King.
Tuning is also slightly different, bass is more visceral and full bodied while retaining top class technicalities.
Mid range is fairly recessed, making it to sound more distant and neutral, not as engaging - warm while treble gets a mild emphasis which enhances detail retrieval and clarity, the IE900 is much more resolving and extended but at the same time it can be a little more bright sounding than the IE600.

Three different offerings from Sennheiser with diverse sound profiles and gradually increasing technicalities that naturally scale with the asking price.

Vs the FiiO FD7 ($600)
(side by side comparison)

FiiO FD7 (review) is another excellent single dynamic driver iem with a slightly different form factor, better accessories, tuning tubes and an excellent modular cable.

Assuming that you don't care about physical appearance, fit, comfort and accessories, let's talk about sound.

With the balanced sound tubes fitted to the FD7, the overall tuning between it and the IE600 is quite close.
Frequency response graphs might suggest otherwise but actually the bass extension is on the same level for both with the FD7 reaching as low as the IE600 while at the same time it is a touch more neutrally tuned without any mid-bass emphasis or bleeding on the mids.
Then the FD7 goes a different path with a bolder, fuller and considerably more visceral presentation, the larger driver is moving more air so dynamic behavior has greater impact while at the same time exhibiting top notch technicalities.
Mid range is so closely tuned between the two and although the FD7 is just a tiny bit more recessed the end result is equally full bodied, slightly warm and sweet with natural timbre and the same level of engagement.
Thus said the IE600 is more mid - centric, more pleasing and addicting in this particular area and as such it will appeal better to people who love their HD650 and are searching for something similar in an iem form factor.
Then there is an emphasis on the presence area, resulting in a more brilliant and resolving presentation from the FD7, with greater extension, more air between the lines, increased clarity and a surplus of energy but without sounding bright or fatiguing.
A key difference is on the soundstaging abilities between the two earphones.
Whether the IE600 is more intimate and into the listener's head, the FD7 reaches outside the head, projecting the soundstage in front of the listener.
The FD7 is grander scale, has better holography and extended width, there is more space around the instruments
with the same positioning accuracy while ambience is communicated in a more convincing manner.



Don't ask which one is better, because both are great and ideally you should audition both in order to choose unless you are an HD650 fan, then you should blindly purchase the IE600.

In the end

The IE600 is the sweet spot of the Sennheiser IEx00 family, sitting in the middle between the IE300 and the flagship IE900.
With one of the best tuned mids after the venerable HD650, balanced and natural, with excellent technicalities and a thoroughly musical, easy listening character, this is an earphone suitable for a blindfolded purchase, you just can't go wrong with it whatever are your listening habits.

Test playlist

Copyright - Laskis Petros 2022.