After reading about the hype surrounding the Sony MH755, a pack-in IEM packaged with Sony XPERIA phones and sold alongside a Bluetooth adapter primarily in Japan, I was curious. I’m always on the look out for the next breakout hit IEM in the audiophile world and this one certainly looked to be on its way to becoming just that. One even called it “Sony’s greatest accident“. Others have raved about the MH755’s great price – performance ratio.
But what really caught my attention was the description of its sound, which is to say, the massive sub bass presence. Being the unashamed basshead I am, I couldn’t help but order a pair. Unfortunately, the market for Chinese MH755 knockoffs is thriving and finding a legitimate pair can be rather difficult. One of the surefire ways of getting a legit pair is by buying a Sony SBH56 or SBH24 Bluetooth adapter. So, that’s what I did.
One of the first things I noticed is that the stock tips are pretty bad. They’re designed in the shape of Sony’s famous and beloved hybrid tips but they don’t use the same materials. Instead, they employ a thin silicone that doesn’t fit my ears nearly as well as the hybrids and creating a sub-par seal. Obviously, this is a subjective complaint so YMMV but I immediately made to swap them out. That was when I noticed how fit dependent these are in order to sound right, and the abnormally-sized nozzle is certainly no help in that regard. It’s both too small to work with most tips I have like the JVC Spiral Dots and Sony’s own hybrids and too large to fit tips made for earphones with thin nozzles, like those from Shure, Westone and Etymotic.
Eventually, I settled on the foam Monster SuperTips, which I wish Monster still made. With those tips, I finally managed a proper seal and discovered, in short order, that the MH755 can really sing.
It has a V-shaped sound signature and surprisingly excellent sound quality considering their price. As claimed, the bass and especially sub bass performance is amazing. Not only is the extension fantastic, the texture and rumble are both on point. It’s big, but well-behaved and never sloppy and doesn’t muddy up the lower midrange and can stand up to quite a bit of boosting without distorting to satisfy my desire for teeth-rattling bass that’s not just big, but clean. Without a doubt, I love the bass this thing puts out.
The midrange tends to sound a bit recessed because of the bass and treble emphasis but not lacking in detail or clarity. The timbre is well-executed and male and female vocals sound natural. Treble extension is great and quite clear and airy as well. This earphone simply sounds far better than you’d expect considering its price. It’s dynamic, exciting, highly technically proficient and, perhaps most importantly, fun as all hell. The MH755 is a joy to listen to, and I often find myself picking these over much more expensive earphones in my collection.
At that point, I only had one problem with the MH755, and it was a big one. The MH755 in its stock form features an incredibly short J-cord, a cable design that’s made to go behind your head and is apparently popular in Japan. I, however, hate J-cords. Not only is it a silly cable design in my opinion, but the J-cord attached to the MH755 is too short to be used on its own without an extension, as it’s designed to be used with the Bluetooth adapter clipped somewhere on your person, ideally your chest.
So, following a guide I found on Reddit, I ordered some female MMCX connectors from China, and when they finally arrived (after a few weeks), I broke out my soldering iron, Swiss Army knife and some superglue and got to modding. I had a little whoopsie with the iron and burned a bit of the left earphone (which you can see in my photos) but a little bit of sanding smoothed that out nicely. About a half hour of disassembling, soldering and supergluing later, I had a fully functioning and J-cord-free set of Sony MH755 earphones, with the flexibility to work with any MMCX cable I choose.
Some might say this is too much work for such a cheap pair of earphones but these things are the real deal. Price doesn’t always correlate with sound quality and the MH755, which can be found for around $8 by itself (assuming you can get a legit pair), is proof of that. Give this a better cable and more premium-feeling housings and it could easily be sold for many times its street price.
In all, modding the MH755 was a fun little project, and I’ve gone ahead and bought a backup pair to mod and set aside, just in case. Sony’s MH755 is, in its unmodified form, a great buy on its own purely for its sound quality and cheap price, but if you’re willing to put in the work, or you know someone who can do it for you, they can easily become a fantastically versatile set of daily drivers.