Review written by @Precogvision
Few IEMs enjoy the reputation that Sony’s MH755 does in the budget IEM world; there’s no shortage of individuals and reviewers that will attest to its absurd price-to-performance. Nonetheless, a part of me scoffed at the thought of myself possibly enjoying a $10 IEM. I know, I know - very pretentious of me. It certainly doesn’t help that I don’t really subscribe to the flavors of the month thing. Budget IEMs have a tendency to be massively hyped (always something about being the next giant killer), only to die out just as fast after everyone’s blown their money - rinse and repeat.
As it would happen, though, I finally got around to demoing an MH755 at a small, local meetup. And boy, am I glad I did. I’d listened to quite a few other, more expensive IEM’s that day, but the MH755 ended up being the highlight of the meet for me. I simply couldn’t stop raving about how good it was. Now, in full transparency, the MH755 is only extremely good for the price. It is by no means a giant slayer. But of course, that isn’t going to stop me from shilling it - let’s take a look at why.
These units were kindly loaned for review by Super* Review - thank you! You can find him on YouTube here. At the end of the review period they will be returned, and as always, what follows are my honest thoughts and opinions to the best of my ability.
Source and Driveability
All critical listening was done off of an iBasso DX160 with stock tips and lossless FLAC files. As with most single-DD IEMs, the MH755 requires a bit more juice than you might expect, but I had no trouble getting it to adequate listening volumes.
Because this MH755 was lent to me, I don’t have the original packaging. It’s worth noting that these IEMs are not retailed individually, so included accessories are sparse. I have the MH750 as well, and it basically came with three pairs of tips, a shirt clip, and the IEM itself; I’d imagine it’s the same story with the MH755. Build quality is also pretty...janky, for lack of a better word. Hey, it’s $10, what did you expect?
The main difference between the MH755 and MH750 lies in their cables. The MH755 was designed to be used in tandem with a Bluetooth transceiver, so the cable is short - like, unusably short if you’re going to run it out of a normal DAP or phone. Conversely, the MH750’s cable is longer and comes equipped with a microphone that has push button controls. Both cables use an asymmetrical cable in which one cable, the right one, wraps around the neck, thus keeping a single cable off to the side and out of the way. It’s a pretty interesting concept for sure, albeit one that I don’t think is as popular here in the States.
For these reasons, and the fact that the stock cables are highly microphonic, it's popular to mod these IEMs with MMCX connectors or something similar. You can find a handy, how-to guide here on Reddit.
Frequency response taken off of an IEC-711 coupler. Measurement is raw, and there is a resonance peak at 8kHz.
So what exactly makes the MH755 so good? In a nutshell, its tonality. The MH755 is tuned very closely to the Harman target curve, an aggregate curve of sorts which reflects the ideal sound for the majority of people. This is where I disclaim that not everyone will enjoy how the MH755 has been tuned; after all, the curve does not reflect the minority as closely. But by all accounts, in the most objective sense possible, the MH755 has been tuned superbly.
It’s also no secret that consumer preferences have skewed the Harman target in favor of more bass, and the MH755 is happy to play right along with a fat, juicy sub-bass shelf. Unfortunately, these types of tunings tend to be bottlenecked by their intangibles. And indeed, I often joke - rather crudely - that most cheaper, dynamic-driver IEMs are reminiscent (to me) of scarfing a McDonald’s Big Mac off the street. Sure, it’s satisfying, but not really.
Well...the MH755 is one IEM I can make an exception for. It’s low-end is remarkably controlled, and the shelf slopes off appropriately without bulldozing the lower-midrange. And for the qualities with which I’d qualify a good bass response, the MH755 has them in spades. Bass texturing and transient density are exceptionally good, and they border on having that elusive, “rich” quality to them that I generally only associate with IEMs dozens of times the MH755’s cost. Decay is drawn out to the slower side of things just how I like it, and transient attack is largely devoid of bloat or blunting thanks to the strong sub-bass emphasis. There is nothing, and I mean absolutely nothing, to my knowledge that can top this under $100.
Of course, when an IEM stands out this much in one respect, the rest of the tuning tends to be more lackluster - relatively speaking, at least. Along these lines, I find the MH755’s midrange and treble somewhat unremarkable if not well-done. Let’s talk about some of my issues instead:
- The upper-midrange is fairly elevated, peaking somewhere at around 3-3.5kHz on the unit I measured. My personal preferences lie at around 2-2.5kHz for the ear compensation; consequently, I find the MH755’s midrange presentation too forward and lacking in appropriate note-weight. I’ll wager this benefits the IEM’s resolving capability - sheer resolution, particularly - but it’s a point of contention that simply doesn’t sit well for my preferences.
- Over extended listening, I’ve also found the MH755’s treble somewhat fatiguing, which is ironic considering that it doesn’t really extend much. And it’s not like it peaks egregiously or anything, either. The leading edge of cymbals and higher frequency instruments simply have too much emphasis for my tastes, clashing poorly with the subsequent roll-off. I occasionally get the impression that I’m trapped in a pit of sorts, helped in no part by the MH755’s poor staging, with those instruments bearing down on me.
These are minor nitpicks; I suppose you could argue that my issue is more with the Harman target than anything. I’m also of the opinion that MH755’s intangibles leave something to be desired. Dynamic contrast is poor. There’s a slight downwards compression going on, and I find the MH755 lacking in engagement factor despite the terrific bass shelf. Imaging is also fairly average - you know, three-blob - and staging is firmly confined to the headstage. But it stands that these are all issues that I could say the same of most $100, $200, heck, even $300 IEMs.
To this end, the single-DD has long been hailed as endgame driver material for its natural timbre and coherency; the MH755 puts this sentiment to work. And in terms of more traditional metrics, resolving capability is actually quite good as I alluded to earlier. Whether by virtue of the tuning which emphasizes the upper-midrange, the driver’s intangible performance, or more likely, a combination of both, I don’t ever find the MH755’s transient attack lacking. All said and done? I don’t mind saying the MH755’s pretty darn technical for what it is.
This is normally where I’d rant, nitpick, and whine, except...I almost can’t. The MH755 can be had for around $10 and it practically slams everything in the sub-$100 bracket if we’re going by what is “objectively” the best IEM. Really, and I almost can’t believe I’m saying this, the biggest problem with the MH755 is that it’s too good. They’re faked en mass which makes legit ones difficult to find. Sony also doesn’t retail them standalone; as a result, the cost of buying one has actually gone up over time!
Now, I’m sure some will be wondering about the MH755’s brother, the MH750. For all intents and purposes, the MH750 and MH755 are supposed to be the same IEM sonic-wise, but my ears beg to differ and the graph concurs. The MH750’s bass shelf doesn’t slope out as nicely, taking on some bloat and lacking in the tactility that the MH755 has. Consequently, the lower-midrange also sounds overshadowed, and the upper-midrange loses some of the edge it has on the MH755. It’s still not bad at all! In fact, it’s great for the price, and until I got the chance to A/B directly, I thought it sounded almost identical to the first MH755 I’d heard. Unfortunately, at the end of the day, I don’t have a sufficient sample size to draw concrete conclusions, as unit variance is definitely a thing with these IEMs. Don’t shoot the messenger.
Let’s talk about where you’d go if you do have more than $100 to spend. The next step-up would be the Etymotic ER2XR. You lose some of that juicy sub-bass shelf, but with notable gains in transient attack and control. The midrange of the ER2XR is also more balanced, in my opinion, with less upper-midrange presence. Treble on the ER2XR is more muted in the lower-treble, and about equal parts rolled off to my ears which lends itself to a less offensive sound. Go for the ER2XR if you want something cleaner and more resolving, and stick with the MH755 if you prefer a warmer, bassier sound. Both are very well tuned, and most of the gains you’ll hear with the ER2XR are going to be technicality-wise.
Another solid option is the Moondrop KXXS, or effectively, the Moondrop Starfield. I’d wager that the KXXS is closer to a side-grade than a true upgrade, though. I do think the KXXS has a slight edge in technical performance, particularly in imaging, but whether that warrants the price jump is tough. Both have a more forward upper-midrange, and the KXXS has a more linear, subdued lower-treble like the ER2XR.
I’m more of a flagship IEM snob these days, but stuff like the Sony MH755 forces me to re-evaluate the thrill - and the reward - of the budget chase. And unlike a lot of other budget IEMs, the MH755 actually measures up with its reputation to a large extent. Need I say more? Seriously, just go buy one. This is an IEM every self-respecting, value nut should have in their arsenal. If you don’t like it...well, let’s just say you got a fake. I’m kidding, of course (but it wouldn’t be surprising).