Sennheiser IE 40 Pro

General Information

Sennheiser's entry level offering of their monitoring in ear PRO line-up

10mm Dynamic in-ear monitoring headphones with precise sound at both low and high sound pressure levels; for maximum control on loud stages. Secure fit thanks to ergonomic design and a robust construction suitable for stage use.

Comes in 2 colours...


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Pros: Solid build quality
- Bass tuned for on-stage use with plenty of kick
- Natural timbre and tonality in the mids
- Great vocal reproduction
- Smooth treble with good enough sparkle
Cons: Mid-bass boost might be too much for the bass-averse
- Average resolution in midrange and treble
- Imaging and soundstage are average at best
- Smearing of hi-hats and cymbals in fast-paced drum tracks
The “Pro” moniker has become sort of a meme at this point.

Just look at all those phones flaunting “Pro” at the end for the sake of having a larger display, or an extra camera. What’s professional about that? Who knows.

Sennheiser, however, isn’t here to mess around. The IE 40 “Pro” is indeed meant for professional use, in this case: stage monitoring. The whole Pro lineup is actually quite interesting, with a number of innovations made exclusively for them. The upper end IE 400 and IE 500 models are a bit too detached from the budget realm, thus the IE 40 fills that lower-end gap.

So let’s get on with the review.


(Note: the ratings given will be subjective to the price tier. Definitely the expectations from a $15 IEM won’t be the same as a $150 one, and that’s the approach taken while assigning scores. I bought the IEMs with my own funds, still, Disclaimer)

Sources used: LG G6/G7, Questyle QP1R, Yulong DAART Canary, iPhone SE, Cowon Plenue D

Price, while reviewed: 99 euros. Specs can be found on Sennheiser’s website.

Build: The entire IEM shell is made out of plastic (presumably ABS), and while plastic IEMs are a pet-peeve of mine, there is a good reason behind this. These IEMs need to be lightweight, and should put up well with every day abuse. A plastic shell takes care of both as metal would definitely be heavier. In fact, the shells here are quite sturdy and unless you actually step on them I don’t see why they should break apart.
The IEM connectors are the first innovation Sennheiser has made for this new lineup. Their proprietary connector has an MMCX-like shape but it is elongated, resulting in a deeper, more secure fit and far easier cable-swapping. On the downside, the IEMs rotate easily on this new connector, but that’s a small price to pay for the added durability. Regular MMCX connectors get loose after a few months anyway.
As for the more minute details: there’s a vent-hole at the back that releases pressure. The cable itself is pretty sturdy and utilitarian, with ample strain-relief everywhere esp the L-shaped jack.
Now it’s time to highlight my biggest issue with these IEMs — the finish of the shells. The clear shell especially does not look premium at all with numerous molding marks around the driver housing. The black version fares better on that regard, but still looks cheap.


Accessories: Sennheiser didn’t skimp on much in terms of accessories. You get 4 pair of eartips (1 pair of foams included), a soft carrying pouch and a cleaning tool. The eartips are made specifically for these IEMs and they have a very unique “double click-point” mechanism for fitting which allows for both shallow and deep fit. More info can be found here.
Another thing about the eartips that you should be careful about: they have (acoustic?) filters inside them. This is something I have never encountered before in eartips, and kind of caught me off-guard as I lost the foams on one of the eartips while trying to clean them (yeah, I know).
Needless to say, this makes using third-party tips a bit of a challenge as the IE 40 Pros don’t sound optimal with them. Something to take note of if you’re picky about eartips.
Other than that, my two nitpicks regarding the accessories: lack of a hard case and a 6.3mm adapter. The former would have been a better addition than the flimsy pouch Sennheiser has provided, and the latter would befit the “Pro” moniker of these IEMs.

IMG_20191005_163050.jpg IMG_5192.JPG IMG_3659.JPG

The IE 40 in general has a comfortable fit. It’s lightweight, the tips are of good quality and the IEMs are small enough to fit snugly in your ears and has no hard edges or protrusions to cause discomfort.
However, that memory wire might be a point of contention for some, as I am not a big fan of them myself. They tend to stay in place well once you’ve adjusted them, but it’s something you have to do every time you take them out of your pocket. A minor annoyance, but annoyance nonetheless.



Now, onto the sound. Sennheiser is using a single 10mm dynamic driver here, unlike the usual hybrid/multi-BA IEMs available at this range, so it should be quite interesting.

Lows: The mid-bass boost is immediately noticeable in the IE 40, and it leads to a mild bass bloom that slightly bleeds into the lower mid-range. The sub-bass is not boosted to the same degree, however, and has a pretty noticeable roll-off around 30Hz. You do hear slight sub-bass rumble, but not to the extent of actual bass-head IEMs.
Bass speed is average with a rather natural attack and decay. The bass is not hyper-fast like the BA drivers, nor does it have the “tightness” of certain dynamic driver IEMs. It does add a nice body to the snare hits, as can be heard on Blackfield’s Once. And the extra mid-bass boost is quite useful in stage/commute scenarios, where the surrounding ambient noise drowns out those particular frequencies so due to that particular boost you can hear the bass notes even in noisy environments. That, however, might be a deal-breaker for those who prefer a lean, fast bass response.

Upon first listen in a quiet room, the IE40 Pro’s midrange might seem “recessed” and “distant”. It’s mostly because of the bass boost, however, as the mid-range is not particularly recessed like the “v-shape” bass canons out there that completely ruins midrange tonality.
Sennheiser has gone for a rather unique mid-range tuning in this range. The lower mids are not as scooped as some other models (which usually leads to thinner sounding male vocals and gives a sense of “soundstage width” that is actually messing with the tonality) and there is a very smooth rise up until the 2KHz region. This essentially means that the IE 40 Pro does not focus on male/female vocals specifically and both sound homogeneous. Contrast this to the numerous IEMs out there with a sharp 3KHz peak to gain more female vocal presence (that often leads to shoutiness) and Sennheiser’s focus becomes apparent — they tuned it to have very lifelike vocal representation.
And the vocals indeed are mighty impressive. Damien Rice’s Sleep Don’t Weep has both female and male vocals and showcases this linear mid-range tuning rather well.
However, all is not perfect with the mid-range. The lower-mids sound a bit too full than neutral, so the low-growling vocals in metal tracks tend to sound compressed. Also the upper-mid region could have had 0.5dB or so boost as in stock form, the string instruments lack the initial “attack” or bite, which results in a slightly blunt sounding acoustic guitars, for example. Also, the midrange isn’t exceptionally resolving, so those looking for gobs of micro-details will be disappointed (though in this price-range it’s a bit too much to ask).
All that nitpicking aside — the midrange tuning here is really good in terms of both timbre and tuning and facilitates a laid-back listen.

Sennheiser has gone for a very safe and smooth treble tuning with a couple dB of boost around the 6–8KHz range. This helps in saving the cymbal hits and crashes from the bass bloom, along with giving some sparkle in the upper regions so that the whole IEM does not sound dark. Also, during stage monitoring, the drummer can use them too and not have ear-fatigue later on.
The treble tonality follows the pattern of the mids: natural decay with a slightly blunted attack. It’s well-suited for extended listens.
The issue lies with the upper treble as I found hint of graininess in hi-hats and ride cymbals. For example, in Lamb of God’s Ruin, from 2:40 min onward, the rather brutal drum line doesn’t sound as resolving as it should with occasional smearing of hi-hats and cymbals. Also, as with the mids, overall micro-detail rendition is on the average to above-average scale at best.


Width and height is above average, while the depth is just average. It doesn’t sound congested, nor does it sound exceptionally wide. Do note that soundstage perception changes from one ear to the other, so your mileage may vary.

Central imaging and left-right separation is excellent. You don’t get holographic imaging due to the poorer “cardinal” imaging, i.e. you don’t get the sense of top-right/top-left that well and instrument placement is mostly flat. Instrument layering is above-average.

Sound-wise, these hold their ground solidly against the competition, especially given that there is a shortage of stage monitors in the chi-fi realm. The build is solid, so are the accessories for the most part. Sennheiser also backs them with 2 years warranty, and these should hold their value pretty well over the years as Sennheiser does not discount IEMs that heavily over time (unlike the chi-fi competition). Overall, a solid purchase given the price tag.


Source and Amping:
Be careful about high output impedance sources as those tend to boost the bass even further, making it uncontrolled. Most sources/phones can run these just fine otherwise as the sensitivity is pretty high.


Select Comparisons

Shure SE215: Shure SE215 is (far) inferior in every single facet. Every. Single. One. Case closed.

vs Final E4000: The E4000 costs slightly more than the IE 40 Pro, but shares some similarities: both are single dynamic driver, both has fantastic tonality and timbre and both has a bass-boosted signature. The IE 40 Pro has a heavier bass focus, however. Build quality goes to the E4000, while accessory set is mostly a tie. In terms of comfort, I prefer E4000 personally.
I can’t choose between the mid-range performance here. E4000 is better with string instruments and female vocals on certain tracks, while the IE 40 Pro does male vocals and piano/keyboard better. Treble presence is more noticeable on the IE 40, but the E4000 treble is smoother and doesn’t exhibit the upper-treble graininess of the IE 40. E4000 is much harder to drive.
They are both good options in this price range so you can’t go much wrong with either if you are into that kind of signature.

vs RHA T20i: T20i costs slightly more, but considering the shell type it did feel like a good competitor.
The RHA model wins hands down when it comes to build quality and accessories. IE 40 Pro is more comfortable due to the lighter shell. Tonality and timbre goes to the Sennheiser, as T20i exhibits a metallic “sheen” to its timbre which is more noticeable in vocal-heavy and acoustic tracks.
In terms of bass response, T20i digs deeper with more sub-bass rumble, and has a leaner mid-bass (with the default reference filter). Mid-range tonality goes to IE 40 Pro, and it’s also more forgiving of poorly mastered tracks. T20i shines with well-mastered tracks but will heavily pick out flaws in the recording. Treble is even more extended on the T20i but the upper-treble “zing” can be distracting on certain tracks. IE 40 Pro in contrast has a smoother treble response. T20i outperforms IE 40 Pro when it comes to soundstage/imaging and general technical performance including micro-detail retrieval.
If you are into metal genre/sub-genres or synth-pop/pop, T20i will serve you better with its more v-shaped tuning. For commuting and extended listening sessions across a variety of genres, IE 40 Pro is the easier pick.




Sennheiser has been out of contention in the sub-$100 space for quite a long time. I had my doubts with the new IE Pro series at the start, but the IE 40 Pro was a rather pleasant surprise. The tuning is very mature and definitely meant for professional stage monitoring, it’s comfortable, built well and comes with a great warranty, the cable is more robust than regular mmcx, and the tonality/timbre of these are some of the best under $200.

While neutral-heads and bass-averse ears won’t find ultimate sonic pleasure with the IE 40 Pros, those who listen to a lot of different genres will find a versatile pair of IEMs that is well-suited for using during commute.

It’s a return to form for Sennheiser, and I hope they take the budget scene seriously this time around.


Test tracks (as Tidal playlist):

Test tracks (as YouTube playlist, often updated):

Last edited:
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Pros: Exceptional sound quality: cohesion, balance, and timbre; high-quality build; smooth, robust, full sound; great isolation and fit; outstanding value.
Cons: Grainy upper treble; flimsy pouch.


The Sennheiser IE 40 Pro is a warm and cohesive sounding single dynamic driver (DD) monitor earphone that excels by its natural tonal quality. The image is built on a solid but never overpowering low end.


My first headphone was a Sennheiser: I picked up the HD414 with its bright yellow pads from a flea market in Germany in the late 1970s — and listened to the Clash and Graham Parker & the Rumour, of course on vinyl. Heavenly! And since then, I have acquired another 7 pairs of Sennheiser headphones and as many earbuds and earphones.

Sennheiser is a company based in lower Saxony, Germany, that rose from the ashes of WWII. Founded in 1945 by Prof. Fritz Sennheiser out of Hanover University, they have been innovative mainly in headphone and microphone technology since. The very competent Tyll Hertsens of once ranked Sennheiser as the world’s best headphone maker (“despite the odd screwup”).

Sennheiser certainly did well with their headphones; for example, the HD600 has been a perennial favourite since 1998. With the appearance of smartphones, Sennheiser introduced the CX300 earphones as an alternative to the buds that came with the phones. I saw their follow-up, the CX300B MKII, ranked somewhere as one of the 10 best headphone/earphone buys below $500 back in 2013. These CX300s had great speech intelligibility but an overly muddy bass. The next generation of Sennheiser budget earphones included the very popular and praised Momentum in-ear, which disappointed me somewhat by its rather recessed midrange. In recent years, Sennheiser had been a bit complacent for my taste, missing the rapid developments in the in-ear sector. For example, they have never produced a balanced armature (BA) driver (earphone). Sennheiser claim that a single wideband transducer produces a more natural sound than an array of BAs that introduce a crossover effect…and they may actually be right.

And while holding on to the single dynamic driver designed in-house, the Sennheiser ie40 Pro is the lowest priced one out of a series of three: the ie400 Pro and ie500 Pro are due to release in May 2019. These are true monitors aiming to musicians but they work equally well for recreational listening.

(from the Sennheiser website)


..are the earpieces, a cable with proprietary connectors similar to MMCX that actually work (patent pending); 3 sets of quality rubber earth and 1 pair of foams, a cleaning tool (!) and a pouch that is too small for my liking.


The earpieces of my black review unit are made of softish plastic, similar to the material used in Sennheiser headphones. It feels smooth and so does the cable that has just the right tension not to be springy. The ear mold (“memory wire”) around the ears is thick and soft and sturdy. The cable is detachable (bonus) but the connectors are proprietary (patent pending) — and as opposed to MMCX connectors they are reliable. The eartips are made of the usual thick high-grade rubbers offered in Sennheiser iems. Overall, all plastics and rubbers use are of good quality and I trust the Sennheiser engineers that the materials have the usual longevity. These monitors offer a truly functional design.


The earpieces are small (7 mm in diameter) and rather shallow so that they fit perfectly into my ears without sticking out. The fit is terrific and the thick ear mold is not intrusive while holding the shell firmly in place. The cable has zero microphonics. Isolation is outstanding: if you don’t need these for your band, they will also work well on the city bus or a plane.


I did my listening with the iPhone SE and used the largest included rubber tips. At 20 ohm, the ie40 Pro are very easy to drive.


JK’s tonal preference and testing practice

The big picture: The IE 40 Pro are warm and mildly bassy earphones characterized by their great tonal quality (timbre) and homogeneity. Gone are the dreaded Sennheiser veil and the associated darkness. The overall sound is extremely pleasant without any significant aberations.

The details: What stands out is the strongly reduced bass compared to previous Sennheiser budget models such as the Momentum in-ear, CX 5.00, and CX 300B Mk II. The IE 40 Pro’s low end has its biggest slam rather deep down between 40 and 100 Hz, and the frequency response remains almost linear and a bit forward inclined between 100 Hz through the complete midrange into the lower treble, where it starts dipping at 6 kHz but and it reaches its biggest peaks between 12 and 15 kHz.

The slightly elevated sub-bass and bass form the solid foundation of the tonal image (“Klangbild”). This healthy but never thick low-end adds the volume that makes the IE 40 PRO sound like a headphone. The bass is medium-fast decaying which contributes to the natural timbre and it adds warmth to the image. It stays focused at this level into the sub-bass. The upper bass enhances and colours the lower midrange (male vocals) but at the expense of some clarity and transparency. For the listener, the bass appears to creep up subtly without the classic mid-bass hump. Very pleasant to my ears.

The midrange is not recessed. Both male and female voices sound full and natural. The upper midrange is actually below neutral at the expense of brightness and energy in guitars and female voices. Speech intelligibility is outstanding.

The lower treble is well-dosed and yet well extended without any peaks that could introduce sibilance, harshness, or hardness. The sound is smooth right into the upper treble that compensate for the flat upper midrange and lower treble by introducing some but not too much sparkle and air. The 12-15 kHz area is rather emphasized compared to other single DDs (including the ones mentioned below), which brings cymbals forward — they can sound a bit grainy in some cases. Several others reported this “upper” sibilance” that affects notes high above the voices. But because the treble did not pierce and the bass does not thump, I could turn the volume up on the IE 40 PRO without regret.

The soundstage is average in width but has a good depth and height. Instrument separation and layering are great – but, quite frankly, I don’t really care that much as the timbre is the delightful part: a saxophone sounds like a saxophone, a cello like a cello, and an acoustic guitar sounds like a…you got it.

In summary, the sound is like “aus einem Guss” (extremely homogenous), never fatiguing, and in the end addictive for me.


Sennheiser Momentum In-Ear ($99): This highly praised and by no-means bad single DD model has an overcooked, thicker bass that pushes its quality vocals into the back and produces a somewhat veiled and muffled sound. A simple mod [instructions] brings the midrange forward, recovers some transparency, and reveals its true quality, but still does not produce the depth of the IE 40 PRO. Midrange and treble are similar between the two models with the upper treble being more forward on the IE 40 PRO. Fit of the IE 40 PRO is also better. Overall, the ie40 Pro are a good step up from the Momentum in-ear.

Brainwavz B200 v1 ($120; discontinued):
The original black B200 with their 2 BAs are an underappreciated jewel and one of my all-time favourites. Although both are tuned very similarly up to 3 kHz the B200’s midrange and treble (and therefore the overall sound) is much leaner than that of the ie40 Pro and their low end is more focused on the mid bass. Where they differ substantially is from the upper midrange up, where the B200 starts dropping off at 3 kHz. Cymbals are less forward and voices are less full, more fragile, less three-dimensional and less natural in the B200 v1. The IE 40 PRO sounds fuller at higher volumes, where the B200 v1 get tinny. It lacks the full sound that makes the IE 40 PRO sound like a headphone. The Senns also handle dense instrumentations better. Nevertheless is the lean sound of the B200 v1. appealing. If asked which of the two I’d surrender, I’d say: none. Both are excellent and it is needless to rank them against each other (considering that one is off the market)!

Focal Sphear ($129):
This single DD has a similarly great natural sound, a thicker, less extended and less focused bass bleeding into the slightly recessed and thinner mids, and also more modest treble. The somewhat V-shaped Sphear is less dynamic and darker. Nevertheless are the differences not gigantic and the Sphear’s timbre makes it a great earphone.

iBasso IT01 ($100): The single DD IT01 has a more extended bass, which is nicely textured, but also a tad too strong for my liking. It smears into the lower midrange at the expense of clarity – which bugs me every time I use them (as they are very competent earphones in most other aspects). The vocals department of the Senns is cleaner, richer, and more homogenous wheras the iBasso’s may have more depth but it is also more recessed. In terms of natural sound, there is not much between them. The iBasso’s shells are much bigger and its fancy braided however heavy cable may be more appealing to some. Again, the Senns are more streamlined and pragmatic in this respect: everything works well together.


I have rarely had a product come through my hands that was so well thought out and balanced as the Sennheiser ie40 Pro, from the haptic, isolation, comfort, and fit to the sound. The IE 40 PRO’s strength is that it is just really good in most respects — and it hits a sweet spot, price wise. This is the rare case where I consider going out and buy myself a pair for the commute.

Es lebe das dynamische Treibersystem | Long live the dynamic driver!


The review unit was a loaner sent upon my request with Sennheiser Electronic GmbH & Co KG in Wedemark, Germany, through Sennheiser USA. Dankesehr and thank you everybody involved! The sole purpose of this review was my independent evaluation of the IE 40 PRO’s technical and sonic qualities.

My generic standard disclaimer

About my measurements

This review has been clipped out of a double review from
If you want to see the second opinion by a non-Head-Fier, you will find it there.

Pros: Good Fitting
Detachable Cable
Good details presentation
Cons: Proprietary connector
Might be bright for some people
Sennheiser Electronic GmbH & Co. KG produces a lot of high fidelity products which impressed audiophile community since 1945. Being a family business, the legacy is built and passed down generation to generation without compromising the details. Sennheiser HE-1, the most expensive headphone system is a status that show where Sennheiser stands in this audio market - king of the kings.

During 2018 4th quarter, I had the opportunity to attend grand opening of Sennheiser HE-1 Experience Center in Singapore. The CEO of Sennheiser, Mr Daniel Sennheiser flew all the way from Germany to Singapore to attend this memorable event.

When Sennheiser is mentioned, people will immediately think of their TOTL such as HD820, HD800s and IE800s. Indeed, being TOTL, these gears created high benchmark for competitors to follow their footsteps in the market. Sennheiser does not forget those who do not have deep wallet to invest on the TOTL. Last year, Sennheiser launched a consumer range IEM, IE40 Pro. It is retailing at SGD159.00 in Singapore - attractive right? In this review, I wil slowly introduce the greatness of this underrated gemstone to you in this review!

  • 1 IE 40 Pro
  • 3 Silicone Adapter (S, M, L)
  • 1 Foam Adapter (M)
  • 1 Soft pouch
  • 1 Cleaning tool
  • Impedance: 20 Ohms
  • THD: < 0.1 % (1kHz, 94dB)
  • Frequency response: 20 - 18,000 Hz
  • Cable length: 1.3m (4.3 feet)
  • Attenuation: < 26 dB
  • Sound pressure level (SPL): 115 dB (1kHz / 1 Vrms)
  • Transducer principle: Dynamic
Build, Fit and Isolation
The shell of IE40 Pro is built using plastic. I got the black colour variant which the finishing is a little matte - giving an expensive looks although it is built using plastics. This results the IEM to be lightweight and does not ‘carry any weight,’ even during lengthy sessions. This small housing IEM does sit well in my ears and create a good isolation. I believe the fit will be good for most of the people because of its small form factor.

The cable of this IEM is detachable but as usual, Sennheiser chose a proprietary connector for this IEM like what is done on IE80s. As mentioned by Sennheiser, the cable is deigned with innovative internal cable duct (patent pending) which is fit for stage use. Cable upgrade will be difficult for this IEM now but I hope cable manufacturer can take this connector into consideration.

I used one of my favorite music players, Opus #3 for this review. Cable and eartips are original from the box.

Test Track
  • Hotel California (DSD) - 90/160 on high gain
  • Somewhere, Somebody (DSD) - 90/160 on high gain
  • Billie Jean (24 bit/96 kHz FLAC) - 80/160 on mid gain
  • Misery (16 bit/44.1 kHz FLAC) - 80/160 on mid gain
  • Perfect (24 bit/ 44.1 kHz FLAC) - 80/160 on mid gain
  • Don't Know Why (16 bit/44.1 kHz FLAC) - 80/160 on mid gain
  • Red (16 bit/44.1 kHz FLAC) - 80/160 on mid gain
  • Hello (16 bit/44.1 kHz FLAC) - 80/160 on mid gain
This IEM can be easily driven by DAP or phone. Opus #3 is not a powerful DAP so I need high gain to be triggered for DSD files. Soundstage is always the secret weapon of Sennheiser. Without any disappointment, Sennheiser ace it in IE40 Pro. I think this is the widest soundstage I can get in this price range. It is wide at the X-axis and sufficiently deep at the Y-axis. Impressive! This IEM is sitting in between neutral and bright. I would say it might be described as bright. As a bright signature lover, this fulfill my desire.

I am really impressed by the performance of this mighty IEM at the low frequency region. Solid bass with sufficient depth and it is well controlled. The lows attack fast with synergy and decay fast without bleeding to other frequency region in the spectrum. This is what I describe as quality bass - presence when it is needed, leave when it is not the right time. The DAP I used to review this IEM is not the most bassy one but I believe the lows of this IEM can feed the desire for those bass heads.

For those who read my previous reviews will understand how much I appreciate mids as a pop songs lover especially mandopop. As a matured listener, I believe the mids can be recessed because of the positioning of the staging but the quality should be preserved always. IE40 Pro hits the sweet spot for mids - neither forward or recessed. Nicely sit in the center of the stage, being the star for the stage. Now the show is for the vocalist. Male vocalist like Ed Sheeran sounds full of energy and emotions. When reviewing this IEM, I hesitate to pause the music because I am too into the quality which is presented. The upper mids are breathy and spacious. When I am listening to Jennifer Warnes’s Somewhere, Somebody, the layering is done flawlessly. Her vocal is silky smooth with soul. Very neutral.

Being a bright IEM, the highs are definitely more prominent. A great space is designed for the highs - Spacious and airy without any congestion. The cymbal sounds crisp without distortion. Within this price range, a lot of IEMs have difficulties to present the highs with low noise content but Sennheiser manage to overcome this general issue. It extended well and rolled of well too which results a gentle presentation. It will not torture your eardrums - no piercing highs.

Shure SE215 Speical Edition

SE215 Special Edition is a warm IEM which is one of the favorite for beginners. I like the presentation of SE215 - silky smooth but in term of details presentation, IE40 Pro does a better job. The soundstage is wider and deeper with more space and air. One winning point for SE215 is the use of MMCX connector - easier to find a replacement cable for this IEM.

FiiO F9 Pro
This comparison is a slight disadvantage for IE40 Pro because of the retail price. F9 Pro is in the SGD200 price bucket. F9 Pro utilised three drivers which attracts a lot of beginners - the more the merrier. In term of details presentation, F9 Pro does not perform a lot better as compared to IE40 Pro - both IEMs are on the same par. F9 Pro is a more neutral IEM as compared to IE40 Pro. If you not a fan of bright IEM, F9 Pro might be more suitable for you.

This IEM might be rare for a lot of beginners. I like how RHA build their IEMs - rigid and sturdy. The finishing is supremos. In term of sounds, I find MA75o is colder as compared to IE40 Pro. The emotions presentation is better on IE40 Pros. This is no longer a fight on quality but feel. Colder IEM does ace better in details presentation but MA750 is not far ahead in this region as compared to MA750.

1More Triple Drivers
One of the favorite IEM by beginners - 1More Triple Drivers wins a lot of beginners' hearts. Again, the more the merrier. This is always a misunderstand. I always find the presentation of 1More Triple Drivers is a little bit noisy. The overall presentation is sweet but the distortion is killing me sometime. IE40 Pro presented the music in a leaner and cleaner way which should be appreciated by the community. IE40 Pro is easier to drive as compared to 1More Triple Driver too.

Symphonium Audio Mirage
Symphonium Audio, a Singapore company created 2 IEMs last year. One of them is Mirage. Mirage utilises one B.A driver. Is it another underrated gemstone? Not really. The presentation of Mirage is darker and I always find it blanketed. When my ears are used to the presentation of IE40 Pro, I find Mirage presentation is muffled. This is a clear win for IE40 Pro.

As mentioned in the title, IE40 Pro is really an underrated gemstone within the SGD200 bucket. Clear presentation with proper bass management, IE40 Pro will not disappoint you no matter which genre you are listening to. At the same time, your pocket will love this IEM because you do not need to burn your pocket a hole when you decide to purchase it.

Well done Sennheiser!
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Really enjoyed this, good read and very nice pictures! For the price, I think Sennheiser are going to sell a lot of these! I want one now. LoL
@volly thank you for your support! Yea I highly recommend this IEM! :)


Tested this one shortly and compared it to the Shure SE215.

The Sennheiser IE 40 PRO:
- is brighter;
- has more detail in the highs;
- mids seem equal;
- has more neutral bass;
- has a more comfortable (detachable) cable;
- has a smaller shell, is more comfortable, sits more flush in the ear;
- lacks the sound dampening of the SE215, wind noise does affect it much more.

It's good for its intended use as a live monitor considering its price class.

For me sound dampening is the most important factor, as I can't enjoy music with a lot of wind noise (used when biking). I sent the IE40P back. If wind noise is not a concern and you prefer a more neutral sound, I would recommend the IE40P.
Thanks for the review.

I think those are v-shaped with a significant tilt towards treble. Personally way too much treble!
Bass is well dosed though.