Sony IER-M9 In-ear Monitor Headphones

The IER-M9 is a 5-BA configuration IEM produced by Sony, and it has been on the market for quite some time. I've owned a personal unit for several years, and here are my sound impressions:



Fit and Comfort:
For most of my listening, I've used the Silicon Hybrid tips that come with the packaging. The fit is crucial for the listening experience, as the IEM must conform well to your ear cavity shape and feel snug. It should be a deep fit, so choosing the right tips is essential; otherwise, you might perceive the IEM as too dark-sounding, when it isn't. Once you have the right fit, the M9 is, in my opinion, one of the most comfortable universal IEMs I've tried.


Bass:
The bass doesn't sound like typical Balanced Armature (BA) drivers, but it also lacks the physicality of a Dynamic Driver (DD). What you do get is a decent sub-bass and nice mid-bass warmth, giving it an enveloping feel. However, the level of warmth might not appeal to everyone, especially those who primarily listen to genres like hip-hop or EDM. If you're looking for clean bass with good texture, there are other IEMs on the market, such as the Symphonium Helios.


Mids:
This is one of the more interesting aspects of this IEM. If you've seen the graphs of the IER-M9, you'll notice that its tuning differs from more traditional Harman-tuned IEMs. Despite not being a vocal-centric IEM, it represents vocals very well. The presentation of vocals is somewhat off to the side, as if you're listening to a performance through a screen behind you. The 7th Acoustic Supernova does outperform the M9 in the vocals department.


Treble:
The treble can make or break the sound signature of a warm-sounding IEM. When not executed correctly, it can lead to a dull sound. Fortunately, the M9 has excellent treble extension. None of the treble frequencies sound too peaky to me, and they are well-represented in the air region. The sparkle and cymbal crashes are just right, not piercing or dry. In fact, I use the M9's treble region as my baseline when listening to other IEMs.


Tuning and Technicalities
The M9 has really good timbre and coherency, and despite its warmth, it exhibits pretty good detail retrieval. However, it's not the most dynamic sounding and has rather slow transients. While it does not come off as the most exciting IEM, it still maintains a balanced tuning and can be treated as a reference.

The M9 has a truly impressive imaging capability. It creates a spherical presentation of the music around you, a performance that, in my opinion, is on par with some headphones. While it can be driven off an Apple dongle, it truly shines with more power. The M9 scales remarkably well with source improvements. I've thoroughly enjoyed listening to it through the VMV D1se and the Singxer S-A1 chain. Does it have technicalities that can beat most IEMs priced above it? No, but it's very good for the price range of just under a kilobuck.


Conclusion
Sony, as a brand, is highly trusted in the audiophile community, and they have made a nice addition to this niche hobby with the IER-M9. I've owned my M9 since 2020, and despite some of its faults, it remains a mainstay in my possession. If you enjoy a plain and relaxing evening with some nice jazz, I recommend trying the M9. I believe you will like them.

almost 5 years since its release yet still it remains special for $1000 iem
one of my favorite iem beside sennheiser ie600

build like a tank using magnesium housing & very smooth and non microphonic cable, it might look simple but when i hold it and use it, it definitely feels like TOTL quality

ergonomics is very very subjective but for my ears, using its ML size sony hybrid tips, they fit like a glove for my ears
the only thing preventing me for using them for too long is the lack of any pressure release, after around 2-3 hours i need to take em off for a while to relieve my ears from the pressure buildup due to how sealed they are


sound wise i could categorize them as neutral warm, with very special imaging capability

just a lil bit of note here, they requires power, using 3,5 mm + phone it sounds... mushy and congested, but with proper source and power, man..... they are magical

bass is thick and textured, actually it extends well to the sub bass, somehow it almost feels like dynamic driver, sometimes but because of elevated mid bass, sometimes lacks a bit of sub bass for me, but honestly they are enough and enjoyable for most of my playlist

midrange is so sweet and natural, there's an effortless warmth layer to it but for me it's a "just right" kind of warmth to make female and male voices sounds natural, sweet and romantic,
just a little note though, if you are accustomed to harman/ df neutral kind of ear gain, M9 do feel lacks elevation in ear gain area

treble is strangely unique for me, it is effortlessly extended yet far from any metallic tinge, very smooth, at some songs it does feel laidback but with a a strangely good air extension, for violins like lindsey sterling - dance of the plum sugar fairy, sounds sweet yet has a good bite for the violin energy.

so yeah unique presentation for me, at first you might thought they sound almost dark but when you really listen, it actually extends really well with good bite when needed

also as a full BA driver iem, i feel that they are one of the the most coherent sounding BA i've ever tried from top to bottom sounded complete and coherent, also timbre wise, they are somehow quite close to dd timbre presentation


now technically, again they are uniquely technical in a special way

as an overall they have this warm ish kind of sound that does make the transient a bit blunted, lacking incisive attack and dynamics, resolution wise they are not the best for the price

soundstage is very wide, especially left and right area with good depth
but the magical thing is the imaging, the capability to portray where a certain element either instrument or vocal is coming from... i don't know what kind of thing they have done but man the imaging is certainly magical for my playlist

the thing is.. i've tried (and measured some of them) TOTLs like 64's U12T, U18T, Trio, Fourte, EE Odin, VE phoenix and EXT, even Sony's own Z1R, but none of them could give me imaging like the M9 (yes those iems are objectively better in technical compared to M9 resolution, detail, 3D etc. but the imaging...... the imaging .. is different)

hearing Encanto's OST - we don't talk about bruno : every performer is dancing around my head circling front, left, and right, even i could pick some percussion playing on my upper right to upper left side, it reminds me of a multi speaker presentation from movie theater

hearing Alffy Rev's - Indonesia Wonderland & beauty of Bali : again every percussion, traditional instruments, sounds of birds chirping are playing circling around my head going up and down in a very realistic way

Greatest showman OST - from now on : during the ending session (and we will come back home and we will come back home....) the singers are singing around me, tamborine and percussion coming from my upper head, steps from below, almost feels like i can really imagine the scene in the movie

even other iem might sound more detailed and higher in resolution, but this kind of imaging i have only heard them from M9

so in the end this iem is VERY SPECIAL for me, it might be boring for some due to its lacks of dynamics but for me
everytime i hear it, it feels like i'm sitting on my couch and hearing an analogue warm speaker system that makes every music sounds amazing

currently these two are simply my favorite iems

ie600 is for fun, very dynamics and engaging
M9 is for me during calm time, and when i want to feel that special imaging

ie600 takes me on a thrilling adventure
M9 takes me back to a comfy home

Perfection is a bold statement, i know, but bear with me, i'll explain why i personally think that no IEM gets closer to perfection than this one.

First of all: I used the Sony TA-ZH1ES as source for this review with Xcessor FX4.0 Memory Foam Tips on the IER-M9. I tried all the Silicone ones and third-party ones too (a lot of them including Spinfit, Gel-Filled and all the others that are recommended) but i always had several issues.

Either the sound was less balanced (too much bass or peaking treble) or they caused issues with air pressure. I know that some people like that unbalanced sound more because it sounds more fun, but i personally prefer the more balanced sound with Memory Foam (which allow for air pressure compensation and so guarantee a perfect fit) which is still a lot of fun.

The IER-M9 is my daily driver and i use it mainly with the WM1Z, but there is a noticeable improvement when using the TA-ZH1ES and also a big difference when using it with different DAPs.

I always use the M11 Plus LTD as an reference because its achromatic and you can really hear, that the IER-M9 needs an Sony DAP to shine. They have been made for Sonys Sound Signature and complement them 100%.

tl;dr: for owner of the IER-Z1R. Imagine an more balanced and warm version of the IER-Z1R fixing its main critic point, the mids. If you love the IER-Z1R but thinks it sometimes needs more warmth and more mids, but everything else is perfect, this is your IEM.

Now the review: i'll start with a few songs from Fibel. I've seen them Live and i talked to them in person several times. I know how they sound, i know how they want to sound, what they try to archive and why.

Lets start with the Song Avatar from their current EP Avatar.

Its this ultra warm 80s Rock sound with fat and slammy bass, lots of synth, ambience, electric guitars.

And its just perfect, no other word. Its like standing in front of the band and they play for you. I never heard such an accurate representation of that song with any other Headphone or Earphone in my life. Its ultra detailed but dynamic at the same time. All Advantages of an all-BA setup without any of the disadvantages. If you would give this IEM to anyone who wouldn't know that its an all-BA setup, no one would ever guess that. Most Hybrids i know have an more plastic and lifeless bass, so in terms of Bass, it beats pretty much all Hybrid IEMs out there, with an BA. Its insane.

But its not just the bass, its the overall presentation. How everything sounds real and there, this incredible capability of surrounding you in the music.

The Song Odyssee is the same. Everything is just spot on and as close to the "real thing" as it gets.

Ufo is the next highlight, you have this "noise" in the beginning and some high frequency jitter in the background (did i already mention how extremely forward and detailed, but at the same time ultra soft and organic the treble presentation is?).

The song continues with some background growl and oh my god does this sound authentic.I know i'm repeating myself but i it is that good. There are some "thunder" like sounds and you just feel it. That's the thing with the IER-M9, you feel everything. Every sound is not just a sound, you feel every sound, no matter the frequency. Everything is really there.

And then the Vocals, Drums and Bass join the Song and the bass amp is right here in my room, in front of me.

And then the refrain starts with the synths and the background and you just totally drown in the sound. Its like the music turns into an giant liquid bubble and you're swimming in the middle of it.

So if you have warm songs with slammy bass, lots of dynamic and so on, the IER-M9 is the perfect tool. It represents it truly authentic and accurate. Not the recording, its not an monitoring like sound. You don't hear the limited capabilities of an recorded mix, you hear the real and live performance. The IER-M9 beats pretty much every DD i ever heard in this aspect. Some people use DD only because they dislike BA timbre. If you dislike BA timbre because you want authentic and dynamic reproduction of instruments, this All BA IEM is the ideal IEM for you.

But not everyone cares about warm 80s like recordings, so i'll continue with some electro. I'll start with 4ikais Analogica.

First Song: Meridian Wake and the first few seconds you hear and you're already stunned. I don't know how they did this. You have this extreme speed and accuracy of an BA setup but this authentic DD sound.

The song continues with some high flickering and again, you feel it. Its very high frequency sounds and you feel them.

And then the songs starts and of course, the bass is just perfect. Warm, dark, deep to the depths of hell, slams you in the face but with accuracy at the same time.

I'll continue with Travelling by Night from she on Coloris and it's impossible to listen to that Song with the IER-M9 without instantly starting to smile. The ultra dark background and than this flickering sounds that appear out of nowhere and are really there.

I listened to some more she for the next few minutes because i couldn't stop and also some other groups like CAPSULE or the new Album from きゃりーぱみゅぱみゅ and its the same. Everything sounds authentic, live, real but also extremely direct and fast. You want the perfect IEM for electronic music? Here it is! Speed and precision combined without BA timbre.

But how about instrumentals? Lets start with An Dro from Adam Agee & Jon Sousa.

Oh my god does this guitar sound real. The Violin is on point. You can feel the wood even at the slightest touch of the bow.

And when he plays that high notes on the Violin, there is absolutely no harshness. The treble is forward but so soft and fine. I am a very treble sensitive person and with other IEMs this song can be painfully partly, but not with the IER-M9.

When the song gets more energetic, everything just starts to sound more real and surrounding. You can feel the vibration from the violin reflecting from the walls of the room and the acoustic guitar just kills it.

I'll continue with Take Me Higher from 山木将平 on the Album Twin Best "HIKARI"

With most BA IEM this is the song where the BA timbre really gets bad where the guitar starts to shout in the mids.

But here? Absolutely nothing. Not the slightest touch of BA timbre. Warm, organic, authentic and real. Enjoy your private Solo Guitar concert from 山木将平 wherever you are. Nothing more to say here.

Of course the TA-ZH1ES is a big contribution to this. Try this song with the M11 Plus LTD and it will be less authentic and realistic, so its not only the IER-M9 doing the job here, its the symbiosis of the Amp and the Earphone. With the WM1Z everything sounds a bit more warm and less clear/detailed, especially in the treble, but it still sounds excellent.

So the right source is a must for this Earphone.

Because time is running out, let me continue with some orchestra arrangements. Three Songs.

1. Hans Zimmer --> Interstellar --> Mountains

Oh, my, god. The start of the song with its insane background. You're instantly transported into the orchestra room. You feel the vibration of the walls. Those wood sticks (or whatever that clicking is), its scary how authentic it is. Someone else with more expertise could, without issues, tell me the material of the wood they are made off.

The song continues and gets bigger and bigger and it just transports you out of reality. This one really gets me. And then the actual thing starts with the tubas and everything and you feel the hammering of the drums and everything just sounds big and large but at the same time, you can pick even the slightest details in the background.

And then the Organ! And the Chorus! I'm getting goosebumps again. I'm on my second listen on the WM1Z right now at volume 85 and this is no longer a song, its an experience!

Next song. I decided for 39 (LIVE) from Hatsune Miku played by the Tokyo Symphony Orchestra.

Its recorded totally different than the Interstellar Soundtrack. While with the Interstellar Soundtrack everything merged to one giant experience, this here is more "Hear every instrument separated and layered".

And the IER-M9 does its job here. Positioning of the instruments, layering, separation, timbre of every single instrument. Just perfect.

Its as good as it gets. Especially the part at 02:20 where everything goes quiet and you can feel the air of the flute in your ear and the Double Bass that Plays single strings at 02:29 just sounds so tasty.

It is so hard to describe it but when but the feel of air all the time, especially with double bass and cello, is what makes this IEM so authentic. I had no other IEM and especially not all BA where you had this intense feeling of feeling the vibration of the air.

If the IER-M9 would exist as an Stereo Speaker setup, it would be the most immersive thing that exists.

One last classic Song: Lute Partita in C minor, BWV 997: I. Prelude from Johann Sebastian Bach, played by Gergely Sarkozy

The Story continues. You hear so much more than just the notes playing. the overtones, the vibration of the air and the wood and everything. Most IEM have big trouble reproducing the lower notes on the song here in an authentic way. Not here! It doesn't matter how low Sarkozy goes on the Hapiscord, the sound just gets more angry and dark and moody as it is supposed to be.

So you want the ultimate IEM for classical music? Here it is. I own the IER-M9 since quite some time and listened to so many songs of so many genres. I could go on for hours but i think you got an idea how the Combination of Sony Source + IER-M9 sounds.

It is an realistic, authentic, extremely fast and detailed, but without BA timbre, experience.

It seems that the effort in developing its own BAs really payed of here for Sony. I am so tired of hearing the 1000th variation of Knowles BA timbres in all sorts of In-Ear and IEM, its a very welcome exception to hear a well executed all BA IEM without BA timbre. An IEM that is not all about detail retrieval but also about overall presentation of the song.

The Isolation is very strong to the point that some people might not like it. It is definitely an earplug like feeling. Its my Goto IEM when i go outside. It blocks you from the surrounding noise and you can listen to music at volume 030/120 without issues while noise streets are around you.

### UPDATE ###
Sony recently released new earpieces called EP-NI1000 together with the WF-1000XM4. Even though it might look like they are just meant as an replacement for the WF-1000XM4, they are actually an accessory for all Sony Earphone including the IER-M9

Unlike other Memory Foam earpieces, these are made with an mix of polyurethane and silicone.

After testing them thoroughly, i recommend them as the definitive earpieces of the Sony IER-M9. They are long lasting (unlike memory foam) and they sound like silicone (unlike memory foam).

### UPDATE 2 ###
After testing what feels like all tips on the market i have to revice my recommendation and recommend the COMPLY T-200 for best allround performance (Isoation/Comfort/Sound) and the COMPLY Ts-200 for the best Sound Quality (slightly lower isolation)

Spotify Premium on Mac > iFi ZEN DAC Balanced > iFi ZEN CAN Balanced > IER-M9 w/ Sony Hybrid tips + 4 Core 22AWG OCC SPC Litz 4 cable

I'll keep this brief:

My main drivers over the past year have been the 2014 Sony flagship XBA-Z5. Despite their age, I've yet to encounter anything around the $500 price point that matches their unique speaker-like presentation. I'm primarily a bass and soundstage head, so the Z5 fit the bill nicely, but I wanted to more out of them technically.

I bought the M9 blind, and kept my expectations checked, having read that they didn't match the Z5 in terms of soundstage, and having found the tonality of the all-BA Fearless S8F decidedly uninspiring despite its V-shaped tuning. I had also previously owned the AK T8iE MKII and extensively auditioned the Campfire Andromeda OG, and was frankly underwhelmed by their performance given their entry price.

Let’s just say the M9 has single-handedly disabused me of the notion that TOTL IEMs offer only “incremental refinements” above mid-fi units. To my ears, the M9 sit confidently in a class of their own, just below the IER-Z1R, and well above the AK T8iE MKII, Campfire Andromeda OG, and Fearless S8F.

Crucially, as several users have noted, the M9 are especially sensitive to tip selection and insertion technique. From my listening experience:

Non-ideal fit = Stuffy, overly-warm, thick, laidback, blunted transients, small soundstage

Ideal fit = Clean, quick, precise, open, airy soundstage, extended treble

Due credit to @CoryGilmore for the following tips:

1. Use the smallest sized tip that provides the deepest possible insertion and seal without creating a vacuum/suction effect
2. Pull the top of the ear up and back when inserting IEM—this minimises pressure from within the ear canal, and mitigates the vacuum/suction effect.

Highly recommended.

Preamble:
The Sub 1k IEM market is one which has heated up ferociously in the last few years. Especially with the likes of Chi Fi manufacturers getting traction and even starting their own cult house SQ etc. Makes finding a good bang:sound IEM increasingly difficult.

I have been on this mission for the last 2 years (see my previous reviews). I've been through pretty much all well known manufacturers from 64 audio to campfire audio to beyerdynamic and Sony.

Every time I thought i'd found the one, i'd find myself finding flaws in the SQ or loose interest shorly after.

Right off the bat, these are not neutral nor as some have purported sterile. They are warm and have a slight bass boost.

Now take this with a grain of salt (i'll edit the review later if it changes over the next few weeks), but, the Sony IER M9 are hands down the best most coherent sounding IEM i have ever heard.

Source:
- MBP - 3.5mm
- E1DA G3 - 4.4mm
- Tidal Master
- The M9 even though rated at 20 Ohms responds remarkably to amping, the more power you give them the better and better they sound (much like the Z1R). Balanced is the way to go to power these.

Music Tested:
- Pop, Hip Hop, EDM, Rock and occasional Indie

Unboxing + Accessories:
- Blows everythign sub 1K (aside from the beyerdynamic Xelento which is on par) out of the water. Class act by sony
- Cables are great.
- Nit picking, the case like the Z1R is over engineered and stupidly annoying to store.

Fit:
- Very easy to get a good seal and good fit. The IEMs themselves are very light and contour naturally to the concha.
- The selection of tips allows a fit for everyone, silicone tips do produce at times a negative pressure effect due to venting on the IEM - can be circumvented by superiorly tugging your ear when you insert the M9 or doing a valvalsa whilst it's insitu.

Sound:

- Bass (9.5/10)
Being a self confessed bass head this was my biggest fear getting these IEMs that the bass was going to be lackluster and trash compared to DD bass on the Z1R.The bass on these are exceptional for a BA. Very much comparable to DD bass. These sound nothing like other BA bass (that is the CA Andro's), the bass is thick has a decent amount of rumble and even has the subwoofer effect. Sony have done something marvelous with their inhouse BA drivers. The bass is fast and has great attack. Precise. The only better Bass (technicality wise that is, not quantity) is the Z1R which had even better sub bass extension and rumble. Plenty of other DD and hybrids with more Bass quantity, but none this well executed (if you don't believe me listen to Take me back to london by Ed Sheeran). If the song has prominent bass, you get prominent bass. Never bleeds into mids and is suberbly executed. Well done Sony. -0.5 for the comparitvely less sub bass extension (i know not possible for a BA, but still)

- Mids (9.5/10)
The best vocals i have ever heard on a pair of IEMs, bar none. These outperform the Z1R in the mids easily. Male and female vocals are superbly executed, crystal clear with no distortion. High octave female singers can sound slighly blunted at times, but again minor caveat. On the very rare occasion the upper mids sounded shrill and artificial, however this seemed to be track specific. -0.5 for the occasional shrills (i need to reitorate, very infrequent, maybe more related to track mastering as it was only on 1 to 2 tracks out of 50)

- Highs (10/10)
I've never really been able to assess highs very well. I'm extremely treble sensitive so take what i say here with a grain of salt. The highs are clear and at no point in any tracks was there silibance or harshness. No matter how high you turn up the volume. Cymbals sound accurate and precise. There isn't much ariiness (compared to the Andros) but i never really cared about that.

- Soundstage + Seperation (10/10)
The best seperation out of any of the IEMs i've heard. The layering is simply exceptional. From memory the next closest would have to be the Tia trio which also had great seperation and layering, but after time sounded boring and unentertaining. The sounstage is wide, vocals still sound intimate but not in your face. The coherency is outstanding. These are very easy to listen to for extended periods of time without being being fatiguing.

Summary:
I think i can finally say i have found my endgame IEM. These are simply outstanding. I've gone through so many IEMs which i would keep for a week, a month and sell on. From the moment i heard these i knew they were the ones that will never get sold on. Unfortunately i don't have the previous IEMs to directly A/B but from memory these are a carbon copy of the Z1R with less bass, better mids and substantilly better highs - that is i found the Z1R sibilance unbearable. These easily beat out the CA Andros, Alas, Vega , 64 Audio Tia Trio, EE Legend X, Beyerdynamic Xelento and even Sony's own flagship Z1R. For me this is now the TOTL benchmark.

The Sony IER-M9 originally came out at the MSRP of $1499 but has since dropped down to $999 in recent months. This puts in the shouting distance of other multi-BA IEMs like the Hidition Viento and the Moondrop S8. Unfortunately, I have not had a chance to hear the S8 yet, but I was very excited to try the IER-M9 and see how it stacks against my custom Hidition Viento-B.

This unit was sent on loan to me by community member, tma6. Thanks!

Unboxing

The IER-M9 is a 5-Balanced Armature driver in-ear monitor that features a black magnesium housing with a carbon fabric looking decal in the front. The shell is very lightweight, surprisingly, and feels premium. It also is very comfortable in my ears and I had no issues wearing these for long periods of time due to the nice shell design, weight, and comfort. The cable is also wonderful to use.

In fact, the silk-braided cable is housed in a nice soft rubbery-sheath that is easy to move around, unwind, and doesn't tangle easily. It terminates in an L-connector of both 3.5mm and 4.4mm varieties. Yes, there are two cables included in the box. The connectors of choice for the Sony IER-M9 is mmcx, it fits in a recessed opening on the M9 shell.

In addition to the cables, the M9 comes with 13 sets of tips to choose from, as well as a carry case, and a series of other accessories. The unboxing for the M9 is quite nice, though still lacks to the drawer box approach of the IER-Z1R.

Sound Impressions
The Sony IER-M9 was mostly paired directly with my Sony NW-ZX507 digital audio player for the majority of the time I used it for this review. I also did try it alongside the Topping A90/Schitt Bifrost 2 combination, and an iPhone 5S. The Sony-Sony pairing is a popular one in the community and I've seen a lot of impressions of the M9 paired with the 507, so I was excited to see how these aligned with my own thoughts.





As general blanket statement, I found the Sony IER-M9 to have a warm, enjoyable and extremely coherent signature with outstanding mid-range and and generally laid-back and almost boring sound signature. I use the term "boring", not necessarily in a negative way. It's just an inoffensive sound signature that doesn't have any stand-out feature in its tonality/timbre that makes it either wrong, colored, or the like. I wouldn't necessarily call the IER-M9 reference tuning, as I do find it a little warmer and a little dark, but not overly colored.

Let's start a little differently this time that my normal reviews. I find the M9's coherency outstanding. The multi-driver setup seems to be well designed and doesn't show any disjointed sound across the board. Add to that the really strong resolution, and it seems like Sony knows a thing or two about how to make a good sounding cross-over setup and maximizing each driver's potential.

In the same sense, this is the same experience I found with the Hidition Viento in both the universal and the custom versions. Like the M9, it also featured great coherency and good resolution despite having less drivers than other models which tout tons of drivers. More does not always mean better.




To go on further with the comparison to the Viento-B, I find that both share a lot of similarities. The M9 does have 1 additional BA driver, but both are priced similarly now, and have outstanding mid-ranges where everything just sounds accurate and reproduced well. They both do lack some of the resonance and natural decay that comes inherently sometimes with the use of a standard balanced armature driver, but that's fine for their use cases.

Where I do find that they differ a little bit is in the tuning. The Viento is more reference neutral to me, and when compared to the IER-M9, the Viento has a more focused upper mid-range and even treble region, that may sound a little bright and lean compared to the M9. The M9's additional warmer lower-midrange also adds more body to the sound, and one can't really go wrong with either of these for a solid multi-BA setup under $1K. It's more about picking your tonal preferences.

Okay, I skipped a bit from my normal routine, and now I not only spoiled how I feel about the M9, but also how I compared it to what I consider it's biggest competitor in it's price class. Let's move forward with some music discussion.



I found the M9 to really go well with singer-songwriter type music. I listened to a lot of James Taylor with the M9, and really enjoyed how it presented the softer acoustic guitar songs of the famous musician. The bowed bass guitar on "Fire and Ice" has a nice amount of rumble can be pictured just slightly behind the rest of the instruments in this track, lying a little further back in the scene with its soft growl. The guitars are just over to the left of my hearing, and Taylor's voice is dead center, perhaps a slight bit to the right. The effortless vocals are shown in all their greatness with the M9, and the warm body really helps give his tender vocals in this track some character.

I didn't talk a lot about imaging characteristics a lot until just now, and I do think overall that the M9 excels in this area. It has a nice soundstage that isn't exactly wide or super deep, but it's a good playing field that's above average width and in the upper tier in terms of depth. This allows instruments to sound well separated and it makes the M9 sound open and free of chaos in the most chaotic tracks like Daft Punk's Contact.

The entire lead-up to the finale of this track sounds very detailed and intricate on the M9. The kick bass hits with some authority even if it does not have the slam and decay of typical dynamic driver like it's older sibling, the IER-Z1R. The cymbal crashes sound accurate but not over-done and this constant beating can sometimes be fatiguing on many headphones and in-ears. Again, what is most impressive on the M9 is how effortless it handles the battlefield of this track, with instruments smashing in all directions as it leads to its final build-up and closure. There's no muddiness, no meshing of sounds, and no blunted sounds. Everything comes in well-defined and clean.

My current addiction drug is Tingvall Trio, and specifically their "In Concert" live album. I'm finding myself craving the track, "Movie," for it's sweeping piano melodies, and constant snare drum attack, and heavy bass notes that keep everything gelled together. I normally enjoy this type of music with my Viento and Hifiman Arya, both more reference and neutral-bright signatures. But the added bass warmth of the IER-M9 does give the low end a little more body and power to it. The slightly darker treble helps give these types of songs a nice romantic-type sound approach that is easy to enjoy for long periods of time, while not losing any of the soundscape.

Wrap-Up
I've said a lot of praising remarks to the IER-M9 and the question to be asked is, where does it rank and will you buy it?

The second question is a quick, "no." And it's not because I don't like it. I do like it, but I don't find it different enough than what I own now to make it a purchase. I already have the Hidition Viento-B, and its tuned closer to my neutral preference target, and I prefer a little more air, and a little more upper-mid range than what the IER-M9 provides, but in many ways, I could go either set, as a stand-alone multi-BA IEM to use .

As far as the first question, I think the M9 stands on and near the top of the IEM playing field. It's not the best multi-BA IEM, as I still believe that title goes to either the qdc Anole VX or the 64 Audio U12t, but it's that small tier below where the Hidition Viento and Vision Ears VE8 reside for me.

At $1000, I think this is a nice buy that comes with a great accessory package and a great build. It has a few minor flaws, that are more preference things than anything else, but that's typical in this price category where preferences matter more. Good work Sony.

Sony IER-M9: Presenting a new way

It would be too obvious if I try to introduce Sony at this point. Sony is a worldwide electronics company and takes a significant role in the audiophile markets. There are several IEMs that come to my mind when talking about Sony. Their EX-1000 was known for its wide frequency range back in the day when Hi-Res was even a thing. The XBA-Z5, Sony's previous flagship model that has been receiving positive feedbacks. And of course, the twin models - N3AP and N3BP were great as well.

Sony has been quiet with their flagship or premium products since their XBA-Z5, until recently they came up with their new premium line up - featuring IER-M7, IER-M9, and IER-Z1R. Each model houses 4BA, 5BA, and 1BA+2DD. In this review, we will be covering the most common and popular model from the family, the IER-M9.





Packaging

Sony stepped up their game with the packaging for these new flagship line-ups. Inside the box includes a generous amount of accessories along with the earphone. It comes with 6 pairs of Triple Comfort eartips, 7 pairs of Hybrid eartips, a hard case, 2 stock cables (3.5mm/4.4mm), a hard case, a cable strap, and some paperwork. Solely the eartips cost a lot if you try to buy them separately, so I appreciate the generosity.





Variety of eartips: Sony triple comfort / Sony hybrid

The two different stock tips are called Sony hybrid (right) and Sony triple comfort (left). The hybrids tend to snug into the canals close and tight, bringing the sound closer as well as increasing the clarity. The triple comfort, on the other hand, adds a little more bass and provides a similar fit of a foam tip while keeping the clarity. Both types work out nicely with the earphone and recommended give both a try before moving onto aftermarket eartips.





Earpieces - Design

The outer surface is finished with matt black and glossy carbon for the faceplates. Looking simple and premium at the same time. The inner sides are all round-shaped and provide a comfortable fit. One interesting thing is that these do not particularly cause canal pressure while inserting although it does not have any vents either. The shells are made of magnesium alloy, but the surface is finished with a skin-friendly coating which eliminates any metallic feeling to the touch. The earpieces are light, scratch-resistant, and durable.





Earpieces - The specs

IER-M9 sports 5BA drivers per side with 1 low, 2 mids, and 2 highs. All drivers are custom built as well as the soldering materials for the crossovers. Sony claims that they have applied film capacitors instead of ordinary ceramic capacitors, leading to a 90% reduction in distortion.

Another noticeable feature is the structural difference from ordinary BA drivers. For the IER series, the metal structure that vibrates inside the BA drivers are designed to have a T-shaped rather than the original U-shaped, once again reducing the distortion. On top of that, the 2BA tweeters are applied with an additional metal alloy diaphragm and SPC wires used for the inner coil. Finally, the entire set of BA drivers are surrounded by a magnesium alloy structure with gold plated sound tubes, preventing distorting vibrations.





Cables

The two stock mmcx cables are each terminated with 3.5mm and 4.4mm jacks. The cables are made of silver-plated OFC applied with silk-weaved insulations. These cables are very smooth and barely make any microphonics even when I roughly move around. The MMCX connectors on the cables look slightly different than the usual ones, but it works completely fine with other MMCX IEMs and vice versa.





Sound impressions - Bass

First off the bat, IER-M9 does a great job of controlling the reverbs. The reverbs are clear, precise, and never get out of hands. IER-M9 presents a slightly W-shaped signature, having an adequate amount of quantity distributed throughout its frequency range. Nothing feels overdone or unbalanced while sounding rich and plentiful.

M9 brings out a decent amount of ultra-lows and mid-lows. Having them clearly presented, IER-M9's bass reproduction feels very stable, moist, and non-metallic. The bass sports a neutral thickness that punches fast, then clearly decays without getting vague in resolution. Overall the bass feels accurate and rich enough for a monitoring IEM, which never gets overpowering in quantity. I would say the lows are boosted for just about 30% from flat, showing a bass quantity that would normally follow up with a slightly v-shaped IEM.





Sound impressions - Mids

Mids show neutral tonality and it slightly takes a step forward from the lows and highs. It gives me the impression that the five drivers inside IER-M9 seem to be perfectly connected to each other as they provide very consistent and wholesome vocals. There are no signs of phase distortions yet IER-M9 still portrays a bit of 3D effect to the sound, naturally imitating a live stage environment.

Vocals also feel to be neutral in thickness which makes it equally ideal for both male and female artists. Peaks and sibilances are perfectly controlled and the sound is kept to be flowing as stable as possible. The surface is smooth, crisp, and just as the bass did, it does not get metallic in texture. Good move from Sony that they have omitted the metallic characteristics from the sound without degrading the clarity, as it is crucial for monitoring IEMs to bring out as many micro details while keeping the sound comfortable and neutral. It also works out very well with various genres and vocal types which is another important part of making a good monitoring IEM.





Sound impressions - Highs, etc.

Trebles take a gentle approach and show lesser quantity than lows and mids, but that, of course, does not mean IER-M9 compromises in the details. The splashes and airiness on the highs are kept vivid and high in resolution. Well, IER-M7 takes a step further in treble clarity and aggressiveness but IER-M9 would be a more ideal choice for diving into the details without getting fatigued (as well as achieving better bass performance). Trebles from IER-M9 sports an organic, lush texture with smooth edges, making it easily enjoyable for most users.

Staging is on the larger side and spreads out nicely towards the x,y, and z-axis. I would not say this is the largest headroom I have experienced from an IEM, but along with 64 Audio Tia Fourté, IER-M9 brings out one of the best stagings in terms of accuracy and imitating a live stage set. While pumping out a rich and full sound, the staging does not get loosen or flabby, thoroughly respecting its accurate nature.





Eartips / cable matching

Sony always recommends 4.4mm termination and the same goes for the IER-M9. Compared to the stock 3.5mm cable, the 4.4mm one slightly thickens the sound with enhanced ultra-lows and headroom size. Mids gain a little more force and get tighter as well. IER-M9 matches pretty well with different cables and eartips. For cables, I have found silver-based ones to match nicely - Effect Audio Eros II or Acoustune ARC32 for example. These make the upper frequencies to shine even more, but it's really up to your personal taste as well as the eartips. JVC Spiral Dots, Spinfit, Triple Comfort, Hybrid, and others all matched nicely with IER-M9.





Verdicts

Most monitoring IEMs tend to have flat-surfaced vocals, though Sony suggests a different way - to recreate a realistic, lively headroom inside the listener's head. Although IER-M9 has good musicality with a slight w-shaped signature, it hasn't neglected its identity as a monitoring in-ear and presents a sound of "how it is really supposed to be". This makes it possible for professionals users to have better communion with the instruments as well as satisfying average users to enjoy their music. I have no doubt calling this IEM to be an outstanding all-rounder.

Full Review can be found on my site: https://audiorambles.com/sony-ier-m9/


Build Quality, Fit, Comfort and Isolation

Aesthetics (8.5/10): Matte Black shells, decorated with a carbon-fibre faceplate. A classic look, for sure, yet still awfully handsome to look at.

Build Quality (9/10): The housing of the M9 is made with Magnesium Alloy. I can’t say I’ve much experience with the material, but they feel sturdy to the touch. The MMCX connectors are made such that they do not rotate, always a plus in my books for longevity. Included cables are resilient yet fairly supple, and are tangle-proof. All in all, not quite glorious Nippon steel, but fantastic in their own right.

Fit and Comfort (9.5/10): Yes, while you might not think these Frankenstein-looking housings might fit well, they’re actually insanely comfortable and ergonomic to wear. The housings contour to my ears wonderfully, and never feel like they’re in danger of falling out. I could and have worn them for hours at a time without fatigue.

Isolation (9/10): As a general rule, if they fit well, they’ll likely isolate well. The norm, not the exception, the M9 blocks out a substantial amount of noise for your busy commutes on the Subway.

Sound

Bass (8.75/10): During my initial audition with the IER-M9, my expectations regarding the lower frequencies were not set very high – the M9, after all, sports solely Balanced Armature drivers which are often not considered optimal for the reproduction of bass notes compared to traditional Dynamic Drivers. Upon firing up my usual test tracks, however, it was quickly apparent that I had underestimated these little monitors.

The texture, decay and weight of the bass produced by the M9 is eerily similar to that of a DD, high praise for Sony’s in-house made balanced armature drivers. A general weakness of BA Bass is its propensity to sound thin and artificial, but the M9 reveals none of that. The slight bass boost in both the sub and midbass regions raises the “fun” factor, while still exercising excellent restraint. Bass is always exceptionally clean, tight and agile, highlighted by demanding drum-heavy tracks like Muse’s “Neutron Star Collision”.

Sub-bass extension is also fantastic, reaching all the way down to the lowest registers, considerably unique also in its ability to make it “felt” rather than “heard” compared to other BA setups. The rumble did, however, leave more to be desired, lacking the grunt and texture the Z1R can bring. All in all however, it’s stellar bass from the M9.

Midrange (9/10): One of the more frequently levied criticisms of the M9 is that it can sound “boring”, and this sentiment likely stems from the M9’s midrange presentation. It’s without significant peaks, neutral sounding and just ever slightly recessed in terms of stage presentation. The amalgamation of these factors ultimately contributes to bringing about the aforementioned impression many get with the M9.

The midrange however is still very much excellent, with the former mostly an issue regarding personal preferences. I do find myself clamouring for greater midrange presence at times, but objectively, the midrange of the M9 is supremely capable. It boasts fantastic clarity and detail, though perhaps just a fraction behind resolution kings like the 64Audio U12t or the Anole VX, given its greater emphasis on smoothness ahead of transparency, due to the slight touch of analogue warmth present.

Male vocals are some of the best I’ve heard on M9, perfectly conveying the velvety, rich texture of vocals such as Frank Sinatra’s and Andrea Bocelli’s like few monitors on the market can. While their female counterparts do still sound airy and natural, the M9 lacks the sparkle and brightness in the upper midrange register to really make singers like Adele stand out.



Treble (8.75/10): The lower treble on the M9 is exceptionally tuned, with sufficient sparkle to make cymbals and hi-hats shimmer and shine, on tracks like the Jackson Five’s “Want You Back”, detailed with natural decay. Far from what would be considered an intense listen though, it retains the smoothness characteristic of the M9’s sonic signature. Upper treble on the other hand has been tuned down a notch, as instruments like Trumpets on classic Jazz Standards such as “LOVE” or “Autumn Leaves” sounding neutered and unexciting, albeit still with good resolution and articulation. In the same vein, extension is unimpressive, with roll-off evident in the highest registers, once again illustrating the M9’s predisposition to favour a relaxing and non-fatiguing listen over exhibiting sheer technicalities.

Soundstage, Imaging, Separation and Timbre (8.75/10): Even against the backdrop of the prior praise I’ve lavished, the imaging and separation capabilities of the M9 are by far their most outstanding quality. It isn’t hyperbole to say that they’re likely the best I’ve had the pleasure of listening to in that regard. While the stage of the M9 is just slightly wider than average, and its depth relatively unimpressive, the sense of space created by sheer imaging and separation ability will floor you at times, especially in genres like Jazz (Count Basie for example), or live recordings. It’s an experience like no other, and therein lies the “wow” factor of the M9. The M9 also avoids most of the timbre issues full BA setups can have, possessing sufficient weight and decay to its sound. They’re great and generally a non-issue, unless you’re overtly nitpicky or anal about it

Conclusions
As if it were ever in doubt over the course of the review, the Sony IER-M9 gets an easy recommendation from me for those in the market for a warm-neutral type sound signature. For those who want something non-fatiguing to listen to, yet still brimming with technical ability, the M9 checks all the boxes. And you get to unbox a high end Sony product. Furthermore, they’re relatively inexpensive compared to majority of the market in the TOTL department. Did I also mention you get to unbox a high-end Sony product?

All hail our Japanese overlords.

In August 2018, Sony announced 3 new IEMs: the IER-M7, IER-M9, and the IER-Z1R. The IER-M7 is 4BA, retailing at S$799, the IER-M7 is 5BA, retailing at S$1,599, and the IER-Z1R is a hybrid – 2DD 1 BA retailing at S$2,299. While I’ve listened to all three, this review will be primarily focused on the M9. I’ve spent around a week or so listening to them extensively on different sources, and will explain further later on.

Drivers and Specifications

The IER-M9 is a “closed, penta balanced armature” IEM. Here are the technical specifications:
Driver Unit: 5 BA, Magnesium Alloy Super Tweeter
Impedance: 20ohms(at 1kHz)
Frequency Response: 5Hz-4000Hz
Weight: 11g
Sensitivity: 103dB/mW

I feel a need to briefly mention that these are not easily driven – quite a bit of power is needed.


Packaging & Accessories

The IER-M9 comes in a not-so-small package, including 6 pairs of Triple-Comfort earbuds(L to SS), 7 pairs of Hybrid silicon rubber earbuds (from LL to SS), a cleaning cloth, a 4.4mm balanced cable, a 3.5mm cable, a carrying case and of course the IEMs themselves. These are packaged and presented very well. The carrying case is fashionable, but not something that I would bring around everywhere.



Build Quality and Comfort

The IER-M9 is encased in a light but durable outer casing of a magnesium alloy with a carbon fibre plate – a nice touch. The IEM itself features a pre-formed ear hanger with very strong memory, something that may appeal to some but not to others – I found that the hanger was a little bit large for my ears, but not something that would cause discomfort by any means. The MMCX connector is slightly recessed, meaning that you would not be able to attach any other cables unless you have the proprietary connector. The M9 sits snugly in my ears, although there are times that I have felt that it is a touch too big – again nothing to write home about. The isolation and fit is also great, it forms a very good seal to my ears.

With the M7 and M9, Sony has really stepped up its game in the design and comfort categories – in comparison with the MDR-EX1000 and the XBA-Z5, the M7 and M9 look and feel amazing - no more of that odd protruding bits in your ear.

Cables

As stated above, the M9 comes with 2 MMCX cable options, terminating in 3.5mm and 4.4mm balanced. The cables are almost identical apart from the termination and are silver-coated oxygen-free copper cables. The plug is an L-shaped non-magnetic gold-plated stereo plug. I find the cables to be of fairly high quality, they are long and rather sturdy, yet not too heavy. That said, the Y-split and the splitter above could be potentially larger. The M9 is designed to be worn over ear, and there is little to no microphonics at all when moving around with the cable. There is just a small worry that the wire is sheathed in a rubbery material that is just slightly sticky out of the box – hopefully this will not be exacerbated by heat and humidity.


Sound

Before I begin on this section, let me attempt to provide some context – my audio journey has been as such – Vsonic GR07 à Etymotic ER4XR and Massdrop Plus à IER-M9. I’ve spent a lot of time over the past week listening to these gems. Along the way, I’ve listened to a good many of the more highly-rated options on the market, and will be using some of them as select comparisons in this review: Sony MDR-EX1000 (coming soon), Hyla CE-5 and Campfire Audio Andromeda. I find these two IEMs to be the closest in terms of comparison.

Listening preferences – My listening consists primarily of Classical music, both of chamber and orchestral natures. I also listen to a fair amount of Mandopop and some Jazz, and my preferred sound signature being the ever-elusive “perfect neutral”. For this review, I’ve listened to the M9 and other IEMs on the following sources: iBasso DX200, Sony WM-ZX300, Fiio X3ii, Samsung S7 edge.

The first thing that stood out to me when I heard the M9 in the Sony store when trying it for the first time was the coherence and detail retrieval. I find the M9 to have a very natural and coherent sound which still providing a great deal of detail. The M9 can be described to be slightly warm, with a bass boost and some treble shine. While the staging is not extraordinarily expansive, it is both sufficiently wide and deep, and separation and imaging is top notch.

Bass

The M9 boasts a quicker and punchier bass response in comparison with most other BA IEMs. Some may even say that the bass response is slightly overexaggerated – I could sometimes feel the bass beating against my eardrums. The quality of the bass tends to be a bit direct, so it will hit you hard if the track is right. The boost here comes in the subbass, the midbass areas do not feel quite as overpowering. For me, the quantity of bass is just slightly too much, but that is coming from someone whose focus is primarily on Classical music. I feel that the bass would be at least satisfying for most.

Mids

The best way to explain the mids of the M9 would be that it is unoffensive – one would not overly notice the quantity, yet it is not missing, at a quantity that to me is just nice. There really isn’t much to write about this – it just does its job well.

Treble

The treble of the M9 is what I would classify as accurate and extended in a way that is incredibly precise. Piano tracks come out with crystal clarity, Stacey Kent sounds oh so sweet. This is an incredibly addictive sound – the presentation of the treble is so clean. Oh did I mention it still sounds natural? I find that strings in particular sound good in the higher registers, it comes across very clearly, without being shouty by any means.

Imaging and tonality

To me, this is the strongest suit of the M9 – it is fast, accurate and clean, all the while without being in your face. The M9 deals with instruments very well, be in the congested Mahlerian works, or in the more technically challenging jazz tracks. Drums come out tight and clean, and there is a very nice sheen to the cymbals. Plucked instruments – harps and double bass pizzicatos are delightful. I find the M9 to perform particularly well for orchestral and jazz tracks.

Select Comparisons (prices at Singapore MSRP)

Campfire Audio Andromeda (S$1,500)

The Andromeda has clearer spacing in general for any tracks that are less congested (Jazz, etc.), but the imaging of the M9 stands out when dealing with more congested tracks (like full orchestra). The bass response of the Andromeda is slower and less punchy, with a smaller dynamic range than the M9. This is something solved in part by using the Acoustune ARC II cable, which trades some clarity and air for quicker bass response.

I would venture out on a limb to suggest that the Andromeda does the treble range cleaner than the M9, this is probably due to the Andromeda having more space and air than the M9 – this however is a purely personal opinion.

In general, I find the M9 to have a more natural sound and a better tonality than the Andromeda, which as many have raised tend to sound unnatural. If you prefer better bass response and are willing to trade out on some of the “air”, then the M9 would be better for you.

Hyla CE-5 (S$1,600)

The Hyla has a more V-shaped sound in comparison to the M9, with a more noticeable dip in response in the midrange. What the Hyla does better than anything else at this range is bass. While the quantity of the bass for M9 and Hyla is somewhat similar, the quality and tonality of the bass is a fair bit more convincing on the Hyla – it does not quite hit as hard, but with a nuance and well-managed impact that is much more pleasing to the ear. I must note that the Hyla has a very coloured sound – so if you are looking for more “reference”, this would not be for you. The Hyla in general has a more fun tuning as compared to the M9, though is not nearly as technically proficient in terms of imaging and clarity.

Sony MDR-EX1000 (Out of production)

I have yet to be able to do this comparison, so I will update this later.

Etymotic ER4XR (S$499)

It is perhaps slightly unfair to compare the ER4 and the MD+ in the same review as the M9, but I will do so anyway since it was the upgrade path for myself.

The ER4XR has a much more neutral and flat tone, unlike the M9 which is a fair bit more coloured. In terms of technical ability, it provides slightly less in details, but does not quite present them as well. The sound of the ER4 is immensely analytical, even cold, which could make for difficult listening, unlike the M9 which you can listen to for hours.

Massdrop Plus (~S$400)

The MD+ has a fun signature, that is a fair bit more colored than the ER4, sacrificing details and treble extension for more well-managed bass response. What is immediately clear is that the technical ability of the MD+ is nowhere near the M9 (obviously it is an unfair comparison), where it sounds muddy by comparison. Details do not come out as cleanly, and while the midrange performs admirably, there is an obvious roll-off in the treble range that could be a major turn-off for some people.

Conclusion

The IER-M9 is an incredibly technically proficient IEM that does very little wrong, beating out many of the competition at this price point (including CIEMs). It is presented in a very professional packaging, and the sound is excellent. It handles almost all genres with easy, aided by solid performances across the board, with fast and quick response, stellar imaging and plenty of details. While the staging could perhaps be wider, it does not sound intimate, and the boost to the bass is very commendable for BAs, while I find the treble extension to be natural and unforced. At the price of S$1,599, there is little to complain about for this remarkable IEM, which I have absolutely no regrets buying.



The tracks I used for this review are as follows:

Franck Violin Sonata in A Major, 4th Mvt, Kyung Wha Chung
Mendelssohn Octet 4th Mvt, Academy of St. Martin in the Fields
Brahms Piano Trio No.1, 1st Mvt, Maria Joao Pires, Augustin Dumay, Jian Wang
Prokofiev Violin Concert No.2, 1st Mvt, Arabella Steinbacher
Tin Sogno Di Volare (“The Dream of Flight”)(Civilization 6 theme)
Holst The Planets, IV. Jupiter, London Philharmonic, Boult
Mahler Symphony No.2 “Resurrection”, 5th Mvt, Lucerne Festival Orchestra, Abbado
Prokofiev Symphony No. 1 “Classical” 4th Mvt, London Symphony Orchestra, Gergiev
Prokofiev Piano Sonata No.7, 1st Mvt, Pollini
Giacchino The Incredits from “The Incredibles”
G.E.M 泡沫
Jay Chou 听见下雨的声音
Minzy NINANO
Davichi Forgetting You
Suzy, Baekhyun Dream
RPR, Beenie Man DANG DIGGI BANG
Girls Next Door Deep Blue Eyes
Stacey Kent You’ve Got a Friend
Anne Bisson Do What You Please
Frank Sinatra Fly Me To The Moon
Fall Out Boy Thanks for the Mmrs