100+ Head-Fier
How to Spot a Fake - Magical Misunderstood Sony MH750/755
Pros: Harmish (Harman Kardon) Sounding IEM with Extremely detailed Treble and Bass ranges for a very low price.
Cons: Too many "Experts" out there who assume they are Fakes due to the different variants through the ages (Circa 2012-2019) And a confusion via the Interweb that the MH750 and MH755 drivers are different but in fact is untrue and is one and the same.

The MH750/755 variants having such a long history have also been investigated by other hardworking mates. I'm deeply appreciative of their advice and humbly give thanks to them too..and many others not named with apologies, those who I would greatly mention are @crinacle @Slater @TheVortex @axhng @eqsOne @Nuclear Reactor @ClieOS @mochill @aspire5550 and finally @Sead (Member of the Trade: Sony Mobile)

Just again to highlight.. Sony's OEM ( They designed, engineered, and make the prototypes but contract out to others for mass mfg) has 2 iterations of their drivers (pop it open yourself, only takes less than 2 mins with a thick pin ) from 2012-2013/4 (13WK-XX) -Off-centered oval vent & their newer 2015/6/7/8/9 (15WK XX onwards) with centered round vent and they do share almost identical sound signatures except the newer versions has a slightly elevated Mid/Sub Bass,

This was also agreed upon and mentioned by @TheVortex & @aspire5550, as I believe Sony had to work with that, due to different factory contracts, product improvements and cost reductions thru the years, but are very strict on their preferred sound signatures to be as close to their prototype as possible.

How to Find/Buy a unit Today :
(They are getting very rare due to the lack of mass production )

Xperia Phones are Bundled with the MH750 , TYPE: AG-0500/AG-0501 (Black/White) , not MH755 (Shorter cable without microphone)

It's practically impossible now to get the older off-center air vent MH755/750 TYPE: AG-050X version made in 2012/13/14 anymore usually with MFG dates 13WKXX - 2013 Week XX. & 14WKXX - 2014 Week XX

MH750/MH755, TYPE: AG-0500/0501/0502/0506 , Mfg 2015-2019 (Center air vent) , can still be purchased from limited sellers, of course, may also be bought together with the Sony Bluetooth Receiver and recently also spotted the 2019 standalone MH750 Sony retail package

There are also reports of the newer MH755 retail packed with Bluetooth with a Straight 3.5 mm jack instead of a L-Jack and discontinued usage of the CE tagging with Product details on the cable for MFG 2017-2019

Did an in-depth 3 different Types and spent 1-week doing A/B/C testing so you don't have to :

1. MH755 AG-503 - MFG 2013 13WK27 - 2013 Week 27
2. MH750 AG-501 - MFG 2017 17WK42 - 2017 Week 42
3. MH750 AG-500 - MFG 2015 15WK52 - 2015 Week 52

Sony has another new variant mfg in 2019/20, with the straight 3.5mm Jack but since I don't own it or able to buy it ..I'm sorry I will not be able to comment on the sound signatures.

Below an image of the MH750 bundled with the Sony Xperia XZ2 Phone MFG 2017, notice it no longer has any CE markings or labels on the cable

The side vent that started all the confusion on the Internet with the MH755 VS MH750:
TYPE: AG-0503-MH755 (Mfg:2013) AG-0500/1-MH750 (Mfg:2014)

The 1 to 1, 100% Identical off-centered air vent MFG 2013-MH755 & MFG 2014-MH750 whereby the MH750 is super rare as you can't just buy them from any online stores as they are bundled only with Xperia Phones thus why @crinacle made an incorrect assessment in 2019 review and comparison of MH755 (MFG 2013, Side Vent) vs MH750 (MFG 2017, Centre Vent) as they are 2 different hardware variants from different manufacturing periods back then.

The centered air vent, MH 750/755 has various TYPE: AG-050X versions.
2 small eyes MH755.jpg

This is how a fake MH750/755 driver looks like, without the 2 small eyelets, also most likely not secured or glued to the shell, thus in some cases, users have complained of a loose driver when the shells are shaken.

Lord of The Vents ;

In relation to 2013/14 side vent and the later & current common center air vent drivers
In my earliest memory, the MH750 model appeared first before the MH755, via the Ericsson-Sony partnership in 2011/12.

And it shouldn't be a surprise as all Sony Corp Comparison Charts use MH750 naming and not MH755 as to Sony they are one and the same product when it came to comparing with other earphones.

Why the air venting system tech, pray tell? Well due to the small form factor of the MH series from Sony, the vent assist in their microstructures and offers superb bass performances and maintaining detailed clarity with the treble,

Thus why there are always 2 x solder dots to secure the driver/shell from vibrations in Sony IEM, dated as far from the beginning (see Image below of Sony Ericsson W800,MH700, etc IEMs), another awesome example is the microscopic MH1 IEM.

This tech alone shows why Sony is legendary and groundbreaking in audio fidelity even today!

A Myth-Busting Recap :

1. MH750/755 shares the same drivers
2. Only differences are the thin short or longer thicker cable with Mic variants
3. 2 different H/W variants verified through the years

2013/14 - Side Vent Drivers
2015-2020 - Newer Centre Vent Drivers

Both versions can be identified as genuine with Sony's trademarked 2 x Solder Dots

An Extremely rare side vent MH750 mfg 2014 taken from a Sony Xperia Z3-- Yes Side Vent Drivers are not exclusive to only the short cabled Sony uses the same exact drivers with the MH750 too


Good Luck to Everyone :) Now go find this hidden Gem Fast as its getting Rarer (Side Vent MH750/755 ) as we speak :)

Edit/ IMHO I actually prefer the newer centre vent variants MFG in 2015-2019 versions, due to its all-rounded MID/SUB Bass and less peaky treble signatures.
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Nes Nes
This helps a lot!
@Nes Nes , glad it did :) , but always beware of fakes, I had too many encounters too, so be warned :)
is there a difference in sound with 3 of all these types?


100+ Head-Fier
Pros: Incredibly good sound, extremely low price, can also be used as a headset, lightweight, build quality, sits very well in the ear
Cons: -
You can't go wrong with this IEM. Nothing better can be found at this price. And even in the $ 100 price range, it will be hard to find a better IEM. The sound is clear and balanced, the bass is deep and clean. The highs come brilliant. The mids are comfortable.
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100+ Head-Fier
Pros: Very good sub-bass, clean bass with minimal mid bass bleed, good tonality, good timbre, good tuning, price to performance ratio
Cons: Poor build quality, a lot of fakes in the market, requires cable mods
Check out more reviews at:

Setup and price:
1 Dynamic Driver (17 SGD with shipping)


Disclaimer: This review was done by my own accord and I purchased this set at full price from eBay from KANOYA Japan.

The MH755 houses 1 Dynamic Driver and I bought it at about 12 USD (including shipping etc) at the time of my purchase, however its pricing may vary depending on sellers since Sony does not sell it on its own. It is also important to note that there are many fakes out there so do check out for its authenticity before any purchases are made.

Before we dive into build and sound, It is almost a must to do a MMCX modification to it since attached cable is so short which makes it very impractical in my opinion. It costs about SGD 25 to modify it nowadays or you can look up some videos online and do it yourself if you are savvy enough.


My personal unit modified by SG AudioHive (ear tips: Final Audio Ear Tips size M)

Packaging and Accessories (Score: 3/10)

Nothing much to say here since it was an accessory itself, it comes in a plastic package containing the earpiece and tips. However I would like to point out that the stock tips are really good in terms of fit and quality so huge plus for the price you are paying!

Build and Fit (Score: 5/10)

The build here is typical for something like this (the free earpiece that comes with your phone) it is all plastic and not durable so really nothing great here since most of the value comes from its sonic characteristics and performance.
Fit wise, I usually wear it hanging down (unlike over ears) so it really depends on the tips to give you that seal and since given its design, lower your expectations when it comes to seal and fit (stock form) unless you tip roll to something that suits your ear. But I do have to say, it is relatively more comfortable to wear it for long hours as my ears get tired and discomfort from wearing IEMs for too long.


This is where it really shines for this unit, it poses a “Harman-Neutral” sound, good sub-bass extension with a peak in its upper-Mids which some may describe it as V or U shaped (in this case I would classify it as a U-shaped sound signature). The MH755 is fun to listen to, has good timbre and tonal balance for its price and is often described as a “wonder” for many.


Taken from

Sources used: (Topping D10 > Atom Amp) and (Ibasso DX120)

Bass (Score: 8/10)

I really love the sub-bass that MH755 has, it creates that rumble that can really satisfy my sonic cravings and it just became my go-to when it comes to songs with low bass. Mid-bass on the MH755 is relatively less emphasized as compared to sub-bass but it is not lacking or missing, “thumps” are still clean, fast, and textured or in other words, “the dynamic driver kind of bass”. In overall the bass here is boosted but not too much such that it overpowers other frequencies with minimal mid bass bleed.

To elaborate on its bass performance, I would say that I can single out the bass lines clearly despite having other frequencies playing at the same time (including vocals) but does not get in the way of clarity or sounding “muddy” which is something that I really like about it. Quality and quantity bass without losing clarity and tonal balance.

Mids (Score: 7/10)

Mids on MH755 is decent, vocals are clear but slightly recessed or less emphasized. Male vocals tend to sound fuller and deep due to the tuning of bass regions. Female vocals are generally clear however there is a peak around upper midrange (rising from 1khz and peaks around 3khz) which may sound slightly harsh on some songs but generally acceptable for me.

In general, the mids on MH755 are decent, not lacking and they are good enough for me to use it as a point of comparison for anything below SGD 100 which pretty much shows how well-tuned this unit is.

Treble (Score: 7.5/10)

The highs on MH755 are energetic and adds a little sparkle and air to the overall presentation but also at the same time smooth in my opinion (It is not sibilant to me as my sensitive regions ranges from about 7khz to 10khz which in this case is being rolled off from 7khz onward and treble addicts may feel a bit underwhelming.

Sound stage, Imaging and Tonality

Sound stage is pretty decent on this, I was able to feel that space that they recorded those tracks in and I would say it is pretty decent. Imaging on the other hand sounds a bit blurred even in binaural recordings.

An important point for this unit to perform is to achieve that seal and normally, IEM that are 3D printed or have “custom-like” shells can achieve that easily as long as the shell fits your ear properly. However, for the MH755, it is worn hanging down and the TIPS makes the world of difference here as it really diminishes its bass capabilities if you do not get a proper seal. It really depends on the tips that fit your ear but I am currently using slightly larger tips (Final ear tips size M or L) to achieve that seal.

Overall (Score: 8.5/10)

Value is key here because even though modifications are needed, the sonic performance of the MH755 at this price point is just unbeatable. There are other cheap modifications available such as a 3.5mm extension cable (it works but not pretty but it’s the cheapest) which you can explore if you don’t mind the looks. Also build wise it’s below average at best as compared to modern day offerings but for that level of sound, I do not mind buying multiple units just in case if mine starts failing.


I must admit that I was skeptical about the hype for MH755 and thought that it was just of the usual hype trains that people get excited about and then dies off when new products flush the old ones away, but I was obviously wrong. In fact, this might be one of the greatest sucker punches that Sony can pull in the entire audio industry. The MH755 is hard to fault with no obvious flaws or flags that I can think of at this price point and I recommend getting one before it disappears from the world in the future.
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Speed King

New Head-Fier
Pros: Incredible value
Cheap AF
Fun and emotional sound
Bass, subbass
Actual good sized sounstage!
Drums rapresentation
Some songs sound better than almost anything else on these.
Cons: Build quality overall
Almost useless cable (mod pretty much required)
Recessed mids
Possible bass bleed into mids
Would have liked a bit better imaging and separation
Buy them.
Hi everybody!
Today's review is about the Sony MH755, a super cheap earbud that kicks butts like nothing else in this price range.

Let's start with the packaging...
Oh wait, what packaging?


It's a plastic bag... Well, what can you expect at that price? I'm not complaining about it.
Inside it you'll find the earbuds themselves with the medium sized eartips already installed and another plastic bag with two other pairs of tips (large and small).
I got the orange ones, but there could be a chance you can get them in different colors.

Build quality and comfort:

Simply put, very very simple, they have the classic shape of an earbud and are meant to be worn straight down.
The pieces themselves are built out of two plastic parts, and not one of the best plastic... But I don't see them breaking or getting damaged at all. They are small, almost weightless and super easy to take in and out of your ears.

On the upper side you'll see a vent for the driver and on the back you have the Sony logo in gray. The nozzle is pretty short, however it has a lip for the tips and it's covered by what seems a tiny piece of black felt.
The tips are just great, they fit easily in my ears and they are super soft while not giving up to the feeling of being resilient andl durable, I like the color too!


And now the bad part, that damn cable.
Now... I know that the MH755 were included with a BT receiver made by Sony, they want you to put the receiver on your back and walk around, that's why one side of the cable is shorter than the other. (I don't know if all the other units come with the left side shorter than the right, but that's my case)
But since the earbuds are sold separately, people don't always have a BT receiver to strap somewhere on their shoulders...
And it SUCKS.

Aside from the fact that it came extremely junked and almost unusable (I literally had to straighten it with a hair dryer for 15 minutes), it's too short, like, I can't even lower my arm while holding the M3K in my hand below chest-level that they're already pulling down my ears, it's hateful.

It has a right angle plug with a pretty useless strain relief, it's all rubbery and it won't EVER lay flat on a table. Atleast the splitter is decent.


Thanks god that they are easy to mod (it's pretty required there) and I'm soon going to change the cable and put some mmcx connectors or a better cable, that even if attached, it's usable atleast.

Here's an image I took from reddit that shows the entire process:


Comfort here is great, not as good as my Shozy & Neo CP but still solid.
After an hour or something like that I tend to take them out of my ears for about 30 seconds to make them rest a bit.

Pretty easy to drive by just about any source, however, I have to crank the volume a bit higher than usual (about 8 steps more on the volume than the Shozy's on my M3K), and you're gonna hear a touch of benefit going to higher level gear and maybe a bit more of power, since it is a single DD, could add a smidge of more control and tightness to the sound.


Pretty amazing...
I mean that for three bucks you can't get better than these, atleast I don't see how.
They're competing with stuff at MUCH higher prices and I can't understand how they managed to tune wonderfully such a cheap thing.

Their general signature is warm, bassy, fun,
V shaped with some sparkle up top and an intoxicating timbre (in a good way).


Bass: Big, thumpy and impactful, I can see these satisfying a basshead.
It obviously has an elevated amount of it and sometimes it bleeds midly into the mids, but it's rare and almost nonexistent at lower volumes.
The MH755 really shines with EDM, dubstep and with bassy music in general.
And it's not over!

The subbass is boosted too, and when called it shows up with authority and presence and shakes your eardrums like a bartender would shake a cocktail (ok maybe not so much, but we're close to that). In "Smells Blood" from the Devilman Crybaby soundtrack, these manage to literally massage your eardrums with bass.
I usually don't categorize bass as something essential for me as it could be for others, but when something like this shows up, I have nothing to do but appreciate it.
To sum it up, it's a very enjoyable bass response and it's very present, however once in a while it can bother the mids just a bit.

Mids: these are a very controversial part of the sound.
They're generally recessed, and the vocals aren't separated a lot from the mix, sometimes they're even behind it, still pretty clear tho, both for male and female vocals.
Male vocals are rounder and a touch more present due to the bass body, female vocals aren't as forward but still retain cleanliness.
All the instruments in this region are pretty clear, expecially drums (those are special), cellos, lower notes of violins and some other that I can't recall at the moment.

However... On some songs like "I Want You Back" from Jackson 5, the singer is right in your face, all the mids come to life and it's one of the best iterations of that track I've heard.
When the bass starts to play it doesn't bother the rest of the frequencies and the drums on the left are more present in this set than many other headphones or in-ears that I've tried.
In "Cup Of Gold" from Miyamigo, his voice (I presume that he's talking) is so there to the point of sounding lifelike.

So, normally the mids aren't the best offering of the MH755, however on particular instruments and some songs they play them like a boss.

Highs: a bit rolled off while still retaining a decent amount of details and sparkle up top. The treble helps to maintain that mellow, warm sound that these have but when called they can make you dance and move.
Cymbals and strings (trumpets in second place) tend to separate themselves a bit bitter than the other instruments. Once in a lifetime the highs can get a bit too much for my taste, but it's so subtle that I consider this nitpicking.


Soundstage: I think this is the best attribute of these earphones aside bass and subbass.
It's an around your head type of sounstage rather than really outside. On 70% of songs.
Then the other 30% is OUT of your head, it isn't holographic but we're not far from there.
They aren't only wide (on most songs they just go a touch more on the left and in the right than your earlobes, on those wide recorded ones it's about 5/10cm or even more out than that), they display the sound in front of you rather than in your head (depth boi!).
Sometimes, particular sounds in ambient music or similar are behind you or far on the front of your head, imagine my surprise when I listened to stuff from the OPM sountrack or Birocratic.

And in top of that, some of the instruments in very specific songs (Miyamigo, Biosphere, etc.) just sound gigantic and overwhelming (in the best possible way).
Btw, I love sounstage and I consider it an important factor when it comes to sound.

Imaging: eh... It's not that great, I don't think it suffers because of the sounstage, it's just unable to display precisely instruments as well as an hybrid or a balanced armature set nor headphone.
It's not terrible, all I can tell is that it gets better on the sides and the center is a bit missing, I can't see this as a deal breaker, expecially considering the price.

Detail retrieval: Again, good enough, you're not gonna hear the details of higher priced single DD there for sure, but they're not too distant nor lacking.
In the Made In Abyss soundtrack, the plucking of the strings, the deep bass rumble notes and the fingers on the key of the piano are still there, still textured enough to give you a good amount of information.


Dynamics: Pretty good, but not amazing. In "Mountains" from interstellar the drop moved me but didn't blow me away.
I would say that the subbass has the best dynamism with the highs in second place, stuff still manages to jump at you when required.

Realism: Great. These haven't the most clear sound out there, but they can put you in this big, relaxed wash of sound that is super enjoyable and totally compensates for its cleanliness.
Separation: Good not great, in very complex tracks the MH755 can get congested, but not so badly to the point it starts to sound muddy or anything like that. The separation between instruments themselves, expecially some of them (cellos, string instruments, etc.) is pretty nice, however the vocals could benefit from more intimacy and focus.
Tonality: simply put, stellar, it's not the "super natural" kind like the HD600, not even close.
It's like Sprite and water, they look similar, but taste completely different.
The HD600 are uncolored, tight, detailed with that touch of warmth that I personally love.
It's like if you gave the HD600s a tequila shot and then spiced them up.
They're FUN, FUN, FUN all the way through and pretty much intoxicating. The more you listen to them, the more you start to like their sound (I mean, in my case it was love at first sight, but some people may have to adjust to their signature, expecially if they're coming from something more neutral), it's a colored sound for sure, but they're doing it in such a good way...

Forgiveness: Strangely, it doesn't depend on the quality of the file (mp3, flac, wav, etc.), but on how the song was recorded. These sound very good even out of compressed files, and then you find that song that while is in .flac it still doesn't sound as good as that mp3 file sounded.
That doesn't mean you can't manage to discern the differences between a lower quality file and a higher quality file but the difference isn't as big as passing from a bad recording to a good recording.
I know it's weird but that's what I personally can hear.


The only IEM that I can compare to these is the Shozy & Neo CP, priced at 165$ and featuring three BAs (1 Knowles CL22955 and two custom BAs), it doesn't sound fair, right?


Let me tell you, it is, because they are actually comparable and there are some categories where the MH755 obliterates the CP.

Build: Ok this one it's not even funny and I'm going to give it to the CPs, they're much better built, having smooth, solid resin bodies instead of plastic, come with a much better package overall and the cable is on another universe, aside from being detachable too.
About comfort... They are currently the comfort kings out of any headphone or iem that I've tried, however the MH755 are not far off from that.

Bass: The CP doesn't go that deep, It's still present and you can hear it even in complex music, subbass on the MH755 is much more present and plays a much important role in the music, it's rounder, bigger, bolder and better overall. Bass still goes to the MH755 because of it's thump and punch from the DD driver, however it can get overwhelming for the mids at time, however the CP still shows more tightness and more control with virtually no bleed into the mids.

Mids: On the CP are the focus of this iem, they are more present, clearer, more lively and vocals are more present and separated from the mix than the MH755, however on some tracks the MH755 still manages to compete with specific instruments with the CP.
The highs: On the MH755 the highs are a bit rolled off and smoother than the CP, however the CP shows more air up top and more sparkle overall, they have a snappier, crisper sound, and maybe that can get on the nerves more frequently than the MH755 does on some songs (very rare on both tho).

Imaging/sounstage/detail retrieval:
Imaging goes immediately to the CP, they can locate instruments much better and you could point exactly where a sound is coming from.
Sounstage wise, MH755 wins without a doubt, they're wider and deeper by default, while the CP shows everything inside your head, aside from some songs, the MH755 backs everything up and puts the stage in front of you. Not only that, the CP can't display verticality, the MH755 can do a bit of that.
Detail retrieval goes to the CP, they're generally more articulate and accurate, expecially in the mids, however the subbass feels somehow more textured on the MH755.
CP: Neutralish, much more accurate and detailed, what I would call a more clinical sound, very engaging and fast.
MH755: Enjoyment above technicalities, colored, fun, warm, bassy and a generally more appealing sound for a wider range of people.


Oh, what about price to performance?
The MH755 sh*** on the CPs for that, not that the CP sounds bad or anything like that (I think they are still better than the Sonys) but you get what you pay for and maybe a bit more than that (considering all the other attributes).
While for literally 3.15$ the MH755 rapresents one of the best bang for bucks in the audio world, you get a sound that should not be there at that price, competing with, as you've already seen, much higher priced stuff. There are indeed some tradeoffs (build quality, pretty much required cable mod), but the sound makes up for them. Completely.


Still there? Grab your damn wallet and buy a pair, the only problem (aside from that cable) would be that they're only avaliable on aliexpress (1 month or more of shipping time) and eBay as far as I know, and in top of that, there are some fake ones around, so be sure to check the description about the product before making a purchase. I recommend them to anyone who's stepping into audio as much as somebody who owns gear that costs thousand of dollars, just for making them know how three dollars can kick asses in today's world.

Aaaaand... that's it for today, I hope this was useful to you, see you in the next review, ciao!


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Otto Motor

Headphoneus Supremus
Pros: Tonal balance and accuracy; value.
Cons: Useless cable.

This review was originally posted at


This $5-8 cheapo has caught the attentention of the earphone wizards after creating a hype earlier in 2019. Crinacle rates them highly: “Clean notes, proper sub-bass extension and a tonal balance beyond expectations.” Shotgunshane also added them to his list of favourites: “Yup, Seven dollars and 95 cents. Dynamic driver. Universal. Exaggerated Harman type frequency response with large sub bass boost, very clear upper mids and slightly easier going treble. Less warmth than [Sony] MH1/C. Once again Sony makes a budget gem and then screws us over with a J cable.” Antdroid also appreciates the Sonys: “The Sony freebie is exceptionally good for $6-8. It’s included free with their Bluetooth adapters, and a similar model, the MH750, is included with their cell phones. It’s a warm, bassy yet quite coherent in-ear that is quite a bit bassier and warmer than the Harman Target but has a similar upper-midrange and treble curve. It’s a steal for $6 on eBay.” Another qualified earphone guy, B9Scrambler, assigned the Sonys a small soundstage typical for the price range [original statement]. Co-blogger Biodegraded commented the bass was a bit strong for him (I have not heard him ever not say that). The question is: who is right and is the hype justified? The short answer: they are all right, each for their own reasons, and the hype (if there ever was one) is somewhat justified considering the low price and the small risk to lose money on something one doesn’t enjoy.


This is the MH755: single dynamic driver, small earpieces, cable too short (needs extension or recabling), haptic is nothing special. Got my pair from Biodegraded who had purchased them on ebay for $7 AUS.

I put these Sonys first into my ears after a week with the $600 Sennheiser IE 500 PRO [review], which generated a jaw-dropping experience (I had expected the Sonys being slaughtered but the opposite was the case): outstanding tonal balance, clean, natural reproduction. Technicalities are also good: sufficiently wide soundstage with ok depth, good resolution, separation, imaging, layering. No, the Sonys are not better than the Senns, but they excel in the upper midrange: the upper winds and strings of a symphony orchestra are nicely reproduced whereas they are lacking in the better resolving, smoother Senns. Note: the Sony MH755 need quite a bit of juice…while it appears to be preposterous purchasing a dongle amp/dac for a $8 earphone, they work “louder” with my audioquest dragonfly.

To me, the Sony MH755 are like the Toronto Raptors basketball team: every element is good, not much is individually brilliant but everything working together wins matches or even the championship: HOMOGENEITY (=balance) is the Sony’s strength…some may disagree because of the lifted low end. These are simply a delight to listen to for my ears and the main reason may be the tastefully executed upper midrange. Personally, I favour the Sony MH755 over most of my recently reviewed (and much much more expensive) iems, which once again shows that listening pleasure/quality and asking price are frequently not correlated (hence the expensive stuff often has to compensate with window dressing). And even if the MH755 were a bucket of crap in the opinion of others, they still did their job for me by creating pleasure. Isn’t that what we want? MORE JOY OF UNBOXING? Not needed at this price (it comes in a plain baggie).


Frequency response measured by Biodegraded. Bass appears too boosted for what I hear.

So why are all earphone guys mentioned above right imo? It depends where you are coming from. If you listen to classical music, the Sonys will excel by their tonal accuracy (“timbre”), their liveliness, and their homogeneity. If you listen to amplified music, the Sony’s benefits don’t play such a big role. As so often, it is in the eyes of the beerholder. The discussion also shows how much timbre can contribute to the listener’s satisfaction…but it is not mentioned at all in many reviews. Many (expensive) balanced armature earphones may not satisfy the listener in terms of timbre or harmonic distortion. As to soundstage: small or not? I find the soundstage being oval, quite wide rather than deep, with an ok height, but it appears to become smaller with decreasing volume. Add some juice and the soundstage is ok (for my ears).


Does the Chifi holy grail we all have been looking for come from Japan in the end? This is up to you to answer. I usually don’t give buying advice: “If you are in the market for a $xxx earphone, this is a no brainer because it punches above its weight…pull the trigger now” or similar sales blabla. But at $5-8 your biggest risk is getting a fake. Check the ratings of the ebay sellers.

The Sony MH755: There is no reason to be euphoric about them but they certainly are a victory for the dollar-store audiophiles.

P.S. I am lazy and “recabled” by adding a female-to-male audio cable for $2.99. Works.

Hey, what's the length of the extension cable?


500+ Head-Fier
Pros: Clarity everywhere while with Bass
Cons: Cable is Y and short.
This is the best value iem on the market.
I endorse, so it is said.
The cost really disguises the performance of these.
Granted everything man made seems to always gets better; and someday
this too may become eclipsed in value by something better and cheaper.
But life is just moment in time. Happiness is a state of mind. Few things
can turn coal into diamonds, likewise few things can turn money into happiness.
This is one.


500+ Head-Fier
Pros: Timbre
Fatigue-free sound signature
Cons: You could complain about the cheap plastic housings but you'd be nitpicking. The MH755 cost less than two frappaccinos at your local coffeehouse.
20190227_122523-1 (0).jpg

Full review to come but the MH755 is worth re-cabling. The MH755 follows the "Harman In-Ear target" frequency response curve very closely so most people will enjoy these. If you can get a legitimate pair of these at a reasonable price then don't hesitate to re-cable them. At the very least they'd be useful for comparison purposes with other IEMs you're considering purchasing.
I want to mod my one of two pairs of mh755. Which cable will you recommend? Silver or Copper?


New Head-Fier
Pros: 1) Detail amount: just like it's supposd to be - it's just a headphones that work as they have to work: they don't lose details. That's it, there are no details to reveal, headphones can only fail to do what they have to do.
2) Very comfortable. Small, beautiful (well, I just really like Sony design in everything), they disappear in you ears if you'll pick big enough tips.
3) I don't care about the price, but srsly: I've bought two genuine pairs on ebay (don't try amazon, read reviews, you'll find that seller on eBay with no problems) for, like, 24$, including shipping to Russia.
4) Overall tonal balance: first headphones that don't need an EQ.
5) Bass isn't as deep or rumbly, but it's there, it's powerful, it doesn't bleed, sub-bass is deep and can create that basshead-ecstasy feeling.
Cons: 1) VERY short cable.
2) Overall sound is a bit simple, soundstage isn't that wide, layering isn't all that strong. Which is great if you want non-analytical, but music-listening experience, not to listen to disconnected parts of a track. Which is, of course, sometimes awesome, but it gets really old after several months.
Tested them on Massive Attack tracks (why? because they have insane mixing quality with a lot of kinda quiet, background samples), on some black metal, on noise and power electronics albums - they don't fail in any of this genres.
If you want to get really cinematic experience - tame the highs and lows thorugh an EQ, lift mids a bit. Wait for your brains to adapt.
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Noise music? Nice
Tried my pair on The Gerogerigegege, p insane how they sounded sterile compared to my other iems.


100+ Head-Fier
Pros: Dirt cheap
Frequency balance can sound very good
Plays loud with low distortion
Smooth response is easy to EQ
Potential for mods
Cons: Not easy to buy
There are lots of fakes online
Some samples can have too much bass
Short J-style cable
Long-term durability?
Doesn’t come in purple or pink unless you buy the Bluetooth receiver

“The correlation between price and sound quality is close to zero and, slightly negative: r = -.16 (i.e. spending more money gets you slightly worse sound on average).” Sean Olive was referring to the chart below when he wrote that in his blog:

Let’s be fair here. They rate an IEM’s sound quality by how closely its frequency response follows their target curve. We also don’t know how they chose the models in the chart. They certainly don’t include the many, many kinds of $5 junk IEMs that you can buy at fashion discount stores like TJ Maxx and Marshalls, but we get what he’s trying to say. The subject of this review, the elusive Sony MH755, is sometimes the perfect embodiment of the idea.

The bundled earphone
You can’t drive to a store and buy the MH755 by itself. It’s the earphone that comes inside the box with the Sony MW600, SBH20, SBH50, and SBH52 Bluetooth receivers. Several eBay sellers sell replacement MH755 IEMs by themselves for $6 to $8 each. I have a strange love affair with bottom-of-the-barrel cheap IEMs, but I didn’t pay any special attention to the MH755 until I saw the measured performance at Speakerphone’s blog, ClarityFidelity.

Last year, I was experimenting with mods for bassy and v-shaped IEMs by injecting resin into their rear volumes in order to reduce their bass. The process reminded me of the MH755’s smooth measured response. Its midrange and treble follow the diffuse field and Harman target curves closely. I was thinking to myself that all I had to do was reduce the compliance of its rear volume and I’d have the perfectly tuned IEM.

Not long afterwards, I ordered three MH755 from eBay. The first thing I noticed was the short cable, which is designed to be used with a Bluetooth receiver like the SBH20. I use an extension cable with the MH755 when I’m not using it with one—a Radsone EarStudio ES100 in my case. The MH755 has a J-cord design, which means that the cable going to the right earpiece is longer than the one going the left. It’s supposed to go behind the neck on the way to the right ear. I sometimes find the arrangement annoying; I know it’s a deal breaker for some.

What a cheap IEM can sound like
I was surprised when I listened to them straight out of the wrapper. I didn’t hear the huge bass suggested by Speakerphone’s curves. Surely enough, my own measurements showed that my samples don’t have as much bass as the one measured at ClarityFidelity:

Sony MH755 frequency response 3 pairs.png

Frequency response of three MH755 from eBay​

As you can see, my batch of three shows good consistency. I think they already sound very good without mods or EQ. The response at 200 Hz is only ˜1.5 dB up, relative to 1 kHz. At 100 Hz, it’s only 5 dB up. This kind of tuning is uncommon for an IEM that’s not trying to keep the bass flat, like an Etymotic.

The sample that Speakerphone measured is bassier: +7.5 dB at 100 Hz. This boosted mid and upper bass makes the lower midrange sound thick and congested. In fact, the Harman target curve has a low point at around 200 Hz. Many IEMs sound clearer when equalized to decrease the response in this region.

Sony MH755 sample 3 frequency response.png

Sony MH755, frequency response
Top: 2017 Harman In-Ear target compensated
Bottom: Raw. 2017 Harman In-Ear target shown in gray​

The MH755’s bass is a little elevated compared to the 2017 Harman In-Ear target. I prefer less bass than this, less than the target even, which is ok because the curve is just an average. The researchers who created the target prefer less bass themselves. On the MH755, it’s in the lowest octave where I especially feel the exaggerated weight, so I usually shelve the entire bass down with an EQ when it’s available. I still keep some of the bass above flat, but now it’s more in line with my calibrated home theater and two-channel stereo speaker systems (which have subwoofers that extend down to 20 Hz and 25 Hz, respectively).

The MH755’s broad peak at 3 kHz is about 11-12 dB up from 1 kHz, close to Harman’s original 2013 target for headphones. Since then, the curve has evolved, and after some feedback from listening tests around the world, the latest versions of the around-ear and in-ear targets now have the peak ˜2 dB lower. This doesn’t sound like much, but it’s in the area where human hearing is most sensitive. A 2 dB adjustment at 3 kHz is noticeable.

When I tested my own hearing, I discovered that the peak is centered at 3.3 kHz and that the resonance is very strong. An HD600 has a tall peak at 3.5 kHz that bothers some listeners, but it’s a good match for my hearing. Maybe that’s why the MH755’s 3k diffuse-field peak doesn’t bother me that much. It sounds close to what I’m hearing from my speakers. But I can imagine that, for some, the frequency response might give vocals an unwanted glare.

The treble has a smooth response and is free of nasty resonances. I’m hearing a small (seemingly) low Q bump between 7 kHz and 8 kHz. It’s the ear canal's half-wavelength resonance, so its frequency depends on the distance to the eardrum. Speakerphone seems to have inserted the MH755 deeper into the coupler, so the bump is at 9 kHz instead in his measurement. That seems to help fill in the dip in the response above 10k. I can’t insert the MH755 that deep in my ear canal even with the small sleeves.

To my ears, the overall balance is superb, and much better than many expensive headphones and IEMs. The MH755 doesn’t sound out of place in a comparison with well-known models that have stood the test of time.

MH755, HD6xx, ER4PT 4.jpg

MH755 with ER4PT and HD6xx (HD650)​

Two of my three pairs have well-matched left and right channels, and the third is only off by 1-2 dB in parts of the treble. I hear a strong center image, especially with the first two pairs. Within its limitations, MH755’s stereo separation is satisfying and doesn’t call undue attention to itself. I’ve heard headphones and IEMs that play tricks with the phase to try to project a distinctive stereo image. But it’s like looking at shadows at the back of a cave instead of the real thing. It’s laughable when you compare them to a live performance, or even a good stereo or surround speaker system. I suppose it could sound pleasing if the trickery matches your personal HRTF. But it usually doesn’t work for everyone and the result often sounds like a cheap effect that negatively affects the tonality. The MH755 has none of that. It’s a simple minimum phase system.

MH755 with NHTPro A20.jpg

I compared the MH755 to several other cheap IEMs. The local schools here have lost and found boxes, and they have lots of earphones because students lose them all the time. I got to measure several of them. Lost and found gives me an idea of what students are buying. There’s a lot of cheap Bluetooth buds, but I found two KZ IEMs among other Chi-fi models, so my guess is that they’re reading the buzz online. The rest are from my collection.

TL;DR version: I like the sound of the MH755 better than the stock sound of any other cheap IEM that I’ve tried.
All graphs: MH755 frequency response in light gray.

Sony MDR-EX15AP, MH1, MH750.png

Sony MH1 (green), MH750 (blue), and MDR-EX15AP (red)​

The EX15 is the cheap Sony IEM that is sold in the local stores here. It sounds terrible. Maybe there’s a way to mod it to make it sound better. The well-known MH1 has way too much bass for my liking. It sounds good once you take care of the bass by equalizing or modifying the IEM. The two MH750 samples that I have also have too much bass. I don’t know if all MH750 are like this or it’s just my bad luck with these samples. More on this later.

Panasonic RP-HJE120, TCM125, HJE125.png

Panasonic RP-HJE120 (red), RP-TCM125 (green), RP-HJE125 (blue)​

The Panasonic ErgoFit IEMs are very comfortable. They’re also top sellers on Amazon, with thousands of 4+ star ratings. I suppose they sound ok. The TCM125 is the headset version of the HJE125. The difference in the response is probably due variation in samples. I like the older HJE120 better. All of them improve a lot when equalized with a wide dip at 200 Hz. The MH755 still sounds better after that because of its smooth, mostly resonance-free treble and its extended response above 10 kHz.

AKG Y20U, JBL E15, JBL Synchros E10.png

AKG Y20U, JBL Synchros E10, JBL E15​

You would think that these three Harman models would follow their own target curve. Nope: big bloated bass and two sharp resonances in the treble make for an ugly family resemblance. The Wirecutter used to recommend the AKG Y20U, which is, arguably, the worst sounding of these three. Maybe their sample is the good one. They’re now recommending the JBL Live 100 and T210. Perhaps the new models follow the Harman target more closely, but I’m not holding my breath.

Skullcandy Jib, Inkd, Smokin Buds 2.png

Skullcandy Jib (red), Ink’d (green), and Smokin’ Buds 2 (blue)​

Not bad. The muddy Jib is the worst sounding one of the three. But when the bass is reduced via EQ or by sealing the rear volume, it becomes the best-sounding one. It still doesn’t have the high-frequency extension of the MH755. The Ink’d and Smokin’ Buds 2 might have the potential to sound really good after mods. I haven’t tried yet.


JVC Gumy Plus HA-FR6 (red), Gumy Plus HA-FX7M (green), Marshmallow HA-FX32 (blue)​

All of these are current models, according to JVC’s official website. All of them are way more V-shaped than the MH755. I don’t know what happened to my measurement of the HA-FX8 Riptidz, which is also a current model, but it was nothing special anyway. The best of these is the newer Gumy Plus (HA-FX7M) but switching back to the MH755 from any of them gives instant relief.

LG Quadbeat, Quadbeat 3 AKG, Quadbeat 4.png

LG Quadbeat HSS-420 (red), Quadbeat 3 AKG (green), Quadbeat 4 (blue)​

Overall, these Quadbeat models sound pretty good. All can play loud with very little distortion. The best-sounding one out of the box is the Quadbeat 3, which sounds closest to the MH755. The older HSS-420 sounds quite good when you flatten the treble peak at 5.5 kHz and cut the thick lower midrange with an EQ. It's perhaps my favorite after equalizing. Too bad about its silicone sleeves though, which don’t want to stay in my ears.

Philips SHE3550, SHE3595, SHE3855, SHE3905, SHE8105.png

Philips SHE3550 (red), SHE3595 (green), SHE3855 (blue), SHE3905 (orange), SHE8105 (cyan) frequency response​

The Philips family sound: big bass, tall 3k peak, and then two more treble peaks after that. They can sound harsh, depending on what frequency the resonance lands. I like the bass response of the SHE3855 Chromz best. Unfortunately, its midrange has a coloration that I don’t like. Unlike the others, its peak is closer to 2 kHz instead of 3 kHz, and it makes vocals sound a bit shouty. I tested another unit, and its frequency response is basically the same.

The SHE8105 sounds best out of the box, but still not as good as the MH755. It has less bass than the others and its resonances aren’t as sharp. The response is still a little v-shaped. It’s also harder to find at discount stores. I bought the only one I ever saw for $6. The SHE3905 Metalix is much more common. It also has almost as good treble extension as the 8105. Mods can make it sound very good. More on this later.

KZ ED9, ATE, ES4, ED16, ZSN.png

KZ ED9 (red), ATE (green), ES4 (blue), ED16 (orange), and ZSN (cyan) frequency response​

Ok, one more comparison; Chi-fi this time. I chose KZ instead of Xiaomi, Brainwavz, Soundmagic, or HiFiMan. Except for the ED9, all of the ones measured here have the KZ house sound: Lots of midbass, which makes the lower treble somewhat thick, two bumps near 3 kHz, a steep drop in response above 4 kHz, with a valley that goes lower than the level at 1 kHz, then a really sharp spike between 7 kHz and 9 kHz.

The midbass on the ATE and the ES4 are too much for me, even after trying all sorts of tips including wide bore. This boosted response pulls up the low midrange, making it sound thick. It’s better on the ED16 and ZSN, although I would have preferred even less, like on the Sony. Less low midrange gives country music a delightful twang, and the MH755’s steel guitars twang harder than any of the KZs. Equalizing this region down on the KZs improves their clarity. It makes Shawn Mendes sound less chesty, for example. In “Stitches” and “Treat You Better” he sounds more realistically whiny on the Sony, where his expression of angst and anguish is more palpable.

The KZ response falls off steeply after 4 kHz, unlike on the MH755, where it decreases slowly. Dips are usually less offensive than peaks, but here, the KZs are a good 7 to 8 dB lower. Information in this frequency range is being withheld. Snare drums, for example have more snap on the Sony compared to any of the KZs (maybe its attack is slightly too sharp, compared to my speakers). The KZs sound relatively dull here.

The sharp treble spike is the half-wave resonance, so its frequency depends on the insertion depth. In my measurements, the resonance is near 8 kHz. The ES4 and the ZSN, however, have large housings that prevent me from inserting them as deep inside my ears, so I hear the sharp peak near 7 kHz instead. It affects the timbre of cymbals and hi hats, which can sound spitty. On the MH755, it’s a gentler shimmer.

A different insertion depth sometimes results in excessively sibilant vocals. The worst offender of the bunch is the ED16. On “Barbie Dreams”, for example, Nicki Minaj sounds like she’s hissing at you. It’s strangely fitting for a diss track because it arguably intensifies the contempt in her voice. It’s now dripping with disdain. But it’s not the intended effect. The Sony is much more forgiving when it comes to this because its peak is less intense; depending on the amount of damper, it’s just a small bump. Moving that small bump up and down the frequency axis doesn’t result in any range being overemphasized.

KZ IEMS and MH755.jpeg

The MH755 looks different. In this company, it sounds different too. From left to right: KZ ED16, KZ ZSN, Sony MH755, KZ ES4​

I don’t know why KZ does this, but with four different models doing the same thing, it’s definitely a deliberate design choice. Are they trying to simulate the jagged frequency response that the pinna imparts on headphones and speakers, in an attempt to project some kind of stereo image? I don’t think it works for everyone, and it just messes up the tonality. I prefer the MH755’s smooth treble response, even if it’s a little elevated. It’s simple and unassuming and doesn’t try too hard. But that’s me. Your priorities could be different.

MH755 with Dynaudio BM6 2.jpg

Tuning the Response
This section is about EQ and basic mods. It’s mostly about controlling the bass response. January 4 Update: added information on the effect of output tube dampers and foam tips. Enter if you’re interested.
Using an equalizer


Sony MH755 and Radsone EarStudio ES100 Bluetooth receiver​

The MH755’s smooth frequency response makes it easy to apply EQ or crossfeed. For me, simply reducing the bass a little goes a long way. If the Harman target is what you want, a 10-band graphic equalizer can get the response close. Here’s what it looks like with the ES100’s equalizer:


Frequency response with Radsone EarStudio ES100’s equalizer. 2017 Harman In-Ear target shown in gray​


Radsone EarStudio ES100 equalizer settings for Sony MH755​

A 10-band parametric equalizer for the ES100 is planned for a future firmware and app update, so this can get even closer to the target using fewer filters.

Reducing the compliance of the rear volume
If a system-wide equalizer isn’t available, the bass can be reduced by sealing the rear cavity. To do that, block the rear vent, cover the rear cup’s seam all the way around, and seal the bottom where the cable emerges from the rear cup and the strain relief. It can be done temporarily with putty like Blu-Tack.

Sony MH755, where to seal.png

Block the air flow at locations 1-4 to completely seal the rear volume.​

Here’s how it affects the frequency response:

Sony MH755 rear volume sealed (sample 3 R).png

Effect of completely sealing the rear volume.​

I like it. The drawback is that it increases the response between 200 Hz and 500 Hz. This mod doesn’t increase the amount of distortion by much:

Sony MH755 harmonic distortion, rear volume sealed, 3 R.png

Sony MH755 with sealed rear volume, harmonic distortion​

Here’s what happens with a partial seal; keep open the part where the cord emerges from the strain relief (location 4 in the photo above):

Sony MH755 rear volume partially sealed (sample 3 R).png

Effect of partial seal.
Top: 2017 Harman In-Ear target compensated
Bottom: Raw. 2017 Harman In-Ear target in gray​

Depending on how deeply the MH755 has been inserted, this can get the response within 2 dB of the In-Ear target between 30 Hz and 10 kHz. It’s not a huge change, and I would have preferred more bass cut, but it’s noticeable. I like the sound better than the stock MH755, but I’m not sure if I prefer it to the one with the complete seal. To me, it makes solo piano, acoustic bass, bass guitar, and kick drums sound more realistic. Your preferences might be different.

I suppose, if even less bass is desired than possible with a complete seal, we could 1) play with the front vent, or 2) further limit the excursion of the diaphragm by increasing the stiffness of the air in the back volume even more. That could us into the realm of non-reversible mods, e.g., injecting resin in the rear cavity.

Update: January 28, 2019: You can reduce the rear volume via reversible mode: See this post:

The effect of dampers in front of the output tube
The response between 1 kHz and 7 kHz can be controlled by the use of dampers in front of the output tube. Here’s the effect of earbud foam inside the silicone sleeve, in front of the output tube:

Sony MH755, effect of foam dampers in front of output tube.png

Gray: stock Sony MH755
Red: less earbud foam
Green: more earbud foam​

The damper reduces the height of the main peak near 3 kHz and shifts the peak frequency a little higher. It seems to have the most cut around 6 kHz. If you don’t like how the MH755 follows the 2017 Harman IE Target around here, you could use some foam damper. The drawbacks are that it exposes the half-wave resonance more—it was a small nub, but it can grow to a small peak that’s 3-4 dB higher, depending on the amount of damper material. Even a little bit seems to kill the resonance around 14 kHz. Added damping reduces the “air”, which some listeners can still hear clearly, especially those who are younger.

The added damper also makes the graph look closer to the one for the MH1 and one channel of my second sample of MH755, where the 7-8 kHz peak stick out more. It suggests that they have more damping. Perhaps their response can be tuned the other way around by reducing the amount of damper inside the output tube.

I haven’t played with other damper materials like microfiber cloth or tea bags, with or without pinholes. The dampers can be combined with a rear volume seal to make the response less v-shaped:

Sony MH755, damper + complete rear volume seal.png

Gray: stock Sony MH755
Red: added earbud foam damper + rear volume seal​

Maybe this example has too much added damping. Adjust the amount of damper and seal to taste. As always, YMMV.

Starting experiments with foam tips
Here’s what the response looks like with a Comply Sport Pro with Smart Core tip:

Sony MH755 with Comply Sport Pro with Smart Core tip.png

Gray: stock Sony MH755 medium silicone tip.
Red: response with Comply Sport Pro with Smart Core tip​

As expected, Comply foam effectively damps the ear canal’s half-wavelength resonance, so there is no peak near 8 kHz. The big drawback is that it kills the response in the top octave while introducing a peak near 4.5 kHz.

I’ll see if a Sony EP-TC50 replacement sleeve can be made to work with the MH755. It’s the ear sleeve used by the XBA-N3AP. It’s a bit different from Comply foam, but also works as a damper.

Fakes are out there!
Last year I took a risk and ordered three MH755 from an unknown eBay seller. I was lucky to get a good batch. A few months later, I decided to order two MH750, which have microphones and longer cables. I was hoping to get the same performance as the MH755. The seller had the words "100% Brand New OEM and Grade A Quality, NOT Generic, NOT Fake, NOT Replacement" in the page’s item description. Look what I got:

Fake Sony MH750 2 pairs.png

Fake MH750 frequency response?​

As you can imagine, they sounded horrible. I showed the seller this graph and one from the MH755 and explained to him that I was returning the products because they're obviously malfunctioning. It’s possible that these sellers don’t know any better if they’re selling a genuine item or a fake. Who knows where they’re getting their wares? They could have several suppliers themselves.

I don’t remember where, but a few years ago, I read that Sony changed the guts of the MH750 while keeping the exterior the same. The only visible difference is the white filter at the end of the nozzle on the older models instead of a black one. Perhaps I got two original MH750 instead of fakes. I should have taken a photo of the ones I returned.

Update: January 12, 2019
aspire5550 has some excellent information on how to spot fakes: See this post and the next one:

MH755 vs MH750
I ordered two MH750 from an Amazon seller after returning the bad ones from eBay. This time, I’m convinced that I have the real deal, but I’m unhappy with their boosted bass:

Sony MH750 frequency response.png

Sony MH750, frequency response​

After rereading this post by Sead Smailagic, the designer of these MH-series IEMs, it seems that the typical MH750 has a bass response that’s 7.5 dB up, relative to 1 kHz.

This response is similar to the one on the MH755 measured by Speakerphone. On my MH750, the bass boost is closer to +9 dB. On one of them, the left earpiece makes a crinkling sound during insertion—a sign that the driver is bottoming out. My MH750 must not be properly vented in the front. Perhaps the bass can be decreased by restoring the front vent, if I can find it.

I prefer the sound that I’m getting from my three MH755 and their much more controlled bass. What’s not certain is if my samples are atypical and that most units measure like the one at ClarityFidelity, or worse yet, my MH750. That would be disappointing.

Update: January 28, 2019 I modded the MH750 and decreased the bass more than what's possible with a simple rear volume seal. See this post (scroll to the middle):

Low-cost and low-risk alternatives to the MH755
There are many inexpensive IEMs that follow a different target curve, and they have their many fans. But I don’t know anything dirt cheap that sounds like an MH755 out of the box, especially a good one with less bass. My problem with the MH755 is the risk of getting a fake when you order online. Even if you get a genuine unit, you still might get a sample with an obscene amount of bass. What are the alternatives?

The MH750 and MH755 are cheap enough that many enthusiasts can afford to gamble a little bit and order online anyway. If you get a bassy sample, maybe it can be fixed with a simple mod. Buying other IEMs from local discount stores is less risky, and If you’re willing to tinker a little bit, you might be able to might get one of the clearance bin cheapies to sound close.

The graph shown below is what I got last year with the Philips SHE3905 (aka Philips Metalix). I wrote about the experience in this thread:

Philips SHE3905 with reversible mods 2.png

Reversibly-modded Philips SHE3905 headset, frequency response
Top: 2017 Harman In-Ear target compensated
Bottom: Raw. Sony MH755 frequency response in light blue/red.
The resulting frequency response closely follows the Sony’s between 100 Hz and 9 kHz. It sounds similar too. The response between 200 Hz and 400 Hz is a tiny bit higher, but the Sony does that too when fully sealed. I have the bass where I like it. If you want more, don’t seal the rear volume.

It has a few advantages over the MH755: I sometimes like its stronger response between 9 kHz and 12 kHz. It also has a microphone and a longer Y-style cable. The disadvantage is that you have to use a foam tip. And you have to experiment. This is where having a measurement rig helps to shorten the listen-modify cycle time. But I think it sounds lovely, and that the result is worth the effort.

Philips SHE3905 x 3.jpg

The crude Philips SHE3905 can be polished and refined​

Update: January 28, 2019
The Philips SHE8105 is another good one. See this post:

If there are other cheapie IEMs out there that have good potential, I’d like to know about them, their measurements, and how they were hot-rodded.

Sony’s MH series of IEMs has been around for a while. They came out before the first Harman target was published in 2013. But somehow, with the MH755, Sony came up with a smooth frequency response that closely follows Harman’s latest crowd-pleasing target. (That is, if you consider a sample with less bass.) The performance doesn’t end there. It plays loud with low distortion, and it doesn’t suffer from a compressed dynamic range when playing back at high volume.

The Sony MH755 shows what’s possible from a dirt-cheap IEM. It puts to shame many, many products that cost several times its price. Why don’t manufacturers, including Sony, make IEMs like this easily available? I mean, look at the kinds of things that are being hyped as the best low-cost IEM:

Massdrop Hifiman Bolt.png

Massdrop HiFiMan Bolt frequency response​

It sounds worse than the cheapo IEMs from Panasonic, Philips, and Skullcandy. Maybe we should ask Massdrop and Sony to reissue the MH750/MH755, but with a few changes: less sample variation, longer Y-style cable with mic, and more colors available—all of this while keeping the price low. Call it the MH75x or something like that. If a cheap IEM with the performance of an MH755 ever becomes popular, it will become a benchmark, a well-known reference used to compare to other products. It will be easier to call out the many pretenders out there and force manufacturers to step up.
superb deep review!!!! thanks a lot
@yuriv MH750 & MH755 have one and the same exact drivers, the difference is the Mfg 2013/14 side vented drivers Vs the newer centre vented drivers of MFG 2015-2019 , I have enough photo images proof gathered for the last 3 years to dispel this Myth of MH755 is Better than MH750 and set the records straight


1. MH750/755 shares the same drivers
2. Only differences are the thin short or longer thicker cable with Mic variants
3. 2 different H/w variants verified thru the years

2013/14 - Side Vent Drivers
2015-2020 - Newer Centre Vent Drivers

Both versions can be identified as genuine with Sony's trademarked 2 x Solder Dots

Extremely rare side vent MH750 mfg 2014 taken from a sony xperia z3-- Yes Side Vent Drivers are not exclusive to only the short cabled Sony uses the same exact drivers with the MH750 too
Hi @brianforever. I just saw this. I haven't posted in nearly two years, basically putting the hobby on pause since the pandemic began. The world has changed.

When I wrote that report back in 2018, I saw no reason to conclude that the MH750 and MH755 had different drivers. They looked the same and the response above 400 Hz lined up. Doing the mods, I worked with the assumption that the variation in the bass response was due to differences in the compliance of the air in the chamber behind the diaphragm, and possibly the acoustic resistance of the opening leading to the front volume. Put the same driver in a housing that's vented even slightly differently, and you’ll see those changes. I simply chalked it up to manufacturing tolerances and sample variations.

At the time, the only other measurement of the MH750 I could find was Sead's. Since then, much more data has come in from people doing wonderful information gathering like yourself. Please keep it up!