[Slater]

This post is long overdue - this beautiful MH755 was modded by @Slater

In addition to troubleshooting a couple of my beloved IEMs, he built this one for me after discussing what exactly I was looking for. This one is foam modded, has channel indicators, slider bead, silver plated TRN cable, and the stock Sony tag was even transferred - what attention to detail! It sounds sooooo good. I've been listening to this one for months, and randomly listened to my stock MH755 with extension cable (whilst troubleshooting what I thought was a hardware problem - was actually noise present in the recording...) and wow what a difference. I was not expecting to hear such a difference, though my ears had become so accustomed to the modded one, the stock one sounded rather congested/blunted/lifeless by comparison. This is absolutely an all-rounder sounding great with all genres and leaving me not wanting much more as its so easy to just get caught up in the music. Thank you @Slater

Glad you like it!

The stock MH755 is good, but it can definitely be improved upon with excellent results.

 

[MonoJon]

wow what a difference. I was not expecting to hear such a difference, though my ears had become so accustomed to the modded one, the stock one sounded rather congested/blunted/lifeless by comparison. This is absolutely an all-rounder sounding great with all genres and leaving me not wanting much more as its so easy to just get caught up in the music. Thank you @Slater

What accounts for such a big sound improvement? I thought the cable mod was just for convenience, and did not alter the sound (other than hopefully eliminating the terrible microphonics of the stock cable)

 

[colo13]

I use KINPS extension cables and like them a lot, I'm not sure how readily available they are in Spain

Thanks

 

[assassin10000]

What accounts for such a big sound improvement? I thought the cable mod was just for convenience, and did not alter the sound (other than hopefully eliminating the terrible microphonics of the stock cable)

You can remove the foam in the nozzle to change treble. Changing the space inside the rear housing will alter the bass. As will sealing the housing holes or not.


The pair coming to you has a larger knot compared to the original cable, in the rear housing so it will be more balanced sounding. Unmodified other than that, I don't remove the foam in the nozzle. You can undo the knot and use a tiny bit of hot glue instead if you prefer a bassier signature.

 

[MonoJon]

You can remove the foam in the nozzle to change treble. Changing the space inside the rear housing will alter the bass. As will sealing the housing holes or not.

Okay, so in summary, filling the cavity behind the driver will reduce the bass, while removing the "tuning foam" in the nozzle will increase the treble, correct? What will sealing the vent holes do? I think there is one behind the driver and one in front, is that right? I feel like I have read that sealing the vent holes (depending on the IEM you are talking about, and the location of the holes) can either increase or decrease bass. I think I read that taping over the vent holes on the Tin T2 increases the bass - does that sound familiar?

Anyway, @assassin10000, don't bother with removing the knot, especially as I think it requires you to resolder the connections. I have 6 other pairs of these (original cable) coming from various eBay and AliExpress vendors, so I think I'd like a chance to compare you mod to stock and see what I think. I'm hoping to learn to mod these myself, and maybe I can eventually achieve my "ideal" sound signature tweak to these.

Incidentally, I have received two original pairs already, and I am having a heck of a time opening them up - I have tried toothpick in the bass port, fingernails, and cracking them open while wearing rubber surgical gloves to no avail. I can see that I am already marring the area a bit near the bass port just by using my fingernails. What is the trick to opening these? I want to be able to check that they are authentic before my window for returns closes.

 

[Slater]

Okay, so in summary, filling the cavity behind the driver will reduce the bass, while removing the "tuning foam" in the nozzle will increase the treble, correct? What will sealing the vent holes do? I think there is one behind the driver and one in front, is that right? I feel like I have read that sealing the vent holes (depending on the IEM you are talking about, and the location of the holes) can either increase or decrease bass. I think I read that taping over the vent holes on the Tin T2 increases the bass - does that sound familiar?

Anyway, @assassin10000, don't bother with removing the knot, especially as I think it requires you to resolder the connections. I have 6 other pairs of these (original cable) coming from various eBay and AliExpress vendors, so I think I'd like a chance to compare you mod to stock and see what I think. I'm hoping to learn to mod these myself, and maybe I can eventually achieve my "ideal" sound signature tweak to these.

Incidentally, I have received two original pairs already, and I am having a heck of a time opening them up - I have tried toothpick in the bass port, fingernails, and cracking them open while wearing rubber surgical gloves to no avail. I can see that I am already marring the area a bit near the bass port just by using my fingernails. What is the trick to opening these? I want to be able to check that they are authentic before my window for returns closes.

I do many other mods depending on the particular request of the person. It's not just removing the foam and calling it a day.

For example, I test a whole pool of pairs to find volume matched pairs and/or impedance matched pairs. I have also removed the driver and redone the seal, or omitted the seal completely to move the driver closer to the nozzle. On some, I've totally disassembled the shells and bored out and/or radiused the inside of the shell. Also, as you mentioned, the internal volume of the shell can be manipulated to change the sound profile. On the latest MH750 I did, I added new vents to the shell, because the member wanted the sound signature retuned. I've also manipulated the vents on the actual driver itself, which can affect mids and other frequency areas. I also feel it matters what kind of internal wiring I use on the mmcx connector (most people just reuse the stock wire, which I am not fond of), using Cardas audio grade silver solder, etc.

I'm starting to experiment with reshelling the drivers, to see what improvements I can find by totally moving away from the stock Sony plastic shell. The shell has an enormous impact on the end result, even when using the same driver.

Just like headphones, you can do mods that range from mild to wild. If someone wants a simple recable, I can do that. If someone wants 'the works', I can do that too. I continue to test, tweak, and refine my mods as I learn new things that work or don't work. It's a journey of continuous improvement.

Some may say it's a waste, because it's 'only' a cheapy $5 earphone. But I say that alone makes it worth it. I can experiment all I want, and wreck as many pairs in the learning process as I want. At the end of the day, I'm only out a few bucks. If the earphones were $500 a pair, I would not be so willing to rip them apart, do destructive testing, and tinker with them the way I do.

 

[assassin10000]

Okay, so in summary, filling the cavity behind the driver will reduce the bass, while removing the "tuning foam" in the nozzle will increase the treble, correct? What will sealing the vent holes do? I think there is one behind the driver and one in front, is that right? I feel like I have read that sealing the vent holes (depending on the IEM you are talking about, and the location of the holes) can either increase or decrease bass. I think I read that taping over the vent holes on the Tin T2 increases the bass - does that sound familiar?

Anyway, @assassin10000, don't bother with removing the knot, especially as I think it requires you to resolder the connections. I have 6 other pairs of these (original cable) coming from various eBay and AliExpress vendors, so I think I'd like a chance to compare you mod to stock and see what I think. I'm hoping to learn to mod these myself, and maybe I can eventually achieve my "ideal" sound signature tweak to these.

Incidentally, I have received two original pairs already, and I am having a heck of a time opening them up - I have tried toothpick in the bass port, fingernails, and cracking them open while wearing rubber surgical gloves to no avail. I can see that I am already marring the area a bit near the bass port just by using my fingernails. What is the trick to opening these? I want to be able to check that they are authentic before my window for returns closes.

There is only a rear vent on these where the shell halves meet. Where you 'pry' to open. I use a small pick to break the seal and start them open and fingernails otherwise.

As @Slater said, there is quite a bit you can do tuning wise. I only have the change of the knot, as I don't mind a more balanced sound. I also prefer it in case of snagging the cable vs. using a clip or just a bit of glue.

 

[drawun]

Just ordered a pair off taobao for $2.4 each.
Mere months ago there were over 10 stores with these. Now only two still have the listing up, and only one actually has some (~100) in stock.

Could you share the Taobao link, please?

 

[duo8]

Could you share the Taobao link, please?

https://item.taobao.com/item.htm?id=575597051769

 

[gourab1995]

Just did a shell swap for the mh755, with an aluminium one. Conclusion: Youre better off with an mmcx mod or recable. You mess with a single thing of the setup this thing has, with the foam and stuff, and it sounds completely off. After the recable with the original shells itself i was more than content.

 

[Slater]

Just did a shell swap for the mh755, with an aluminium one. Conclusion: Youre better off with an mmcx mod or recable. You mess with a single thing of the setup this thing has, with the foam and stuff, and it sounds completely off. After the recable with the original shells itself i was more than content.

For 98% of people, I totally agree with your statement. Just recable it or mmcx mod it and enjoy.

I am in the freak 2%. Like a Dr Frankenstein, one of my interests in this hobby (besides modding) is building my own headphones and earphones totally from scratch. When you do that, you have to do 100% of the tuning yourself. Sometimes you get results better than the manufacturer, other times you get results much worse.

It can be a lot of work, but it’s also very rewarding at the same time. I have a few headphones where I’ve been working on them on and off for 2 years, doing a dozen different revisions (trying different combinations of drivers, cup dampening, vents, pad tweaks, tuning paper, etc).

One of my future goals is to get all the equipment and skills necessary to make my own CIEM shells. I’ve been slowly working in that direction for a while now, and hopefully I’ll be there someday.

 

[gourab1995]

For 98% of people, I totally agree with your statement. Just recable it or mmcx mod it and enjoy.

I am in the freak 2%. Like a Dr Frankenstein, one of my interests in this hobby (besides modding) is building my own headphones and earphones totally from scratch. When you do that, you have to do 100% of the tuning yourself. Sometimes you get results better than the manufacturer, other times you get results much worse.

It can be a lot of work, but it’s also very rewarding at the same time. I have a few headphones where I’ve been working on them on and off for 2 years, doing a dozen different revisions (trying different combinations of drivers, cup dampening, vents, pad tweaks, tuning paper, etc).

One of my future goals is to get all the equipment and skills necessary to make my own CIEM shells. I’ve been slowly working in that direction for a while now, and hopefully I’ll be there someday.

True, a lot more effort has to be put on for the shell mod to work, i had the idea that creating more empty space in the shell = openness, but also came to the inference that too much and you lose loudness and bass, also affects imaging. Gonna have to play around with the amount of space occupied in the shell and see how the sound changes, also play around with tips. These secondary mods are gonna be a hit and miss thing, that will be specific as to how the modder does it.

Apart from that i think the idea that you can tweak things yourself is quite appealing.

 

[gourab1995]

Here are a few pics of the metal shell mod, tweaking around i found that the little foam piece in between plays a huge role in taming the treble.



Whereas the black filter on the original shell actually kills some of the details.



Overall the metal shell mod has exaggerated treble. Changes subject to tips as well.



Like the normal ones much better, although i think the cable also has something to do with it.



Takes a few tries to master. For contrast here is a pic of my first try, the mh755 potato edition.



To be honest i think the potato edition still sound better than the shell mod version. It has very less bass quantity relative to the originals. The rest is almost the same.

Edit: The metal shells now sound better after using the mh755 tips and inserting the foam with the inner cavity empty,

 

[Damz87]

These would be fakes yeah? When I questioned the eBay seller about the white filters, they said that these came with the MW600 and sent me this link with an unboxing.
https://maizizi.pixnet.net/blog/post/31583263-3c-•-sony-mw600-hi-fi-立體聲藍芽耳機

 

[Broquen]

Think I've never posted before in this thread, even though I own a pair of MH755 for many years, since I bought a Sony SBH50.

Case is lately I've been listening more to them due to circumstances that are not relevant. I have quite some music in wav from Bandcamp, but anyway Tidal+Radsone ES100+MH755 have been a bliss for some weeks too. Missed my daily gear, but felt quite satisfied.

Then last tuesday I received one of that AE purchases wtih some tips added, and tried IE800 model with MH755 (BTW they're sturdy, although not sure if QC is the best). I could not detect any flaw and finally tried with some steadiness... And it worked. I mean in the best possible way.

Won't say more because, as always, every one's mileage may vary. But if somebody owns an ES100 too and wants to try them, I think these tips well deserve the 3,32€ I paid (don't know if they can work on many IEMs, because inner part of the tip (the part that fits the nozzle) is solid, hard plastic).

Anyway, loving the timbre of these little gems more than ever.

The tips:
https://es.aliexpress.com/item/32823543624.html?spm=a2g0s.9042311.0.0.274263c0mxH5cE