OK good news, they are better than my initial impression but they have to be burnt in.
Still need to spend more time with them but with the large pads, they sound pretty good. Good bass , decent imaging, mids seem good, highs are a little recessed, the sound stage is fairly small but i think its due to the small vent holes.
Hopefully getting better padding on the headband will resolve the comfort issues for the most part (they are still really heavy)
Zeos has an upcoming review on a similar model, he was getting better sound from them by removing the back cover. Just by screwing it off.
Hm… interesting idea…
i might look into that, or will wait for the video
Edit: Ill be damned, it just screwed off like a lid, no actual screws… still have to look into the sound but this headphones just seems more and more fun the more i play around with it
Just saw that Zeos did a video on what looks to be The OpenHeart OH2000 or as he mentions one of the many versions of this DIY set that are on AliExpress and also here: Grado Style Open Back Headphone Kit with Metal Cups (Black) – Earphone DIY Labs.
I’ve had the OpenHeart OH2000 for a long time now (pretty much ordered them as soon as they showed up on AliExpress) and tried all kinds of configurations to try get the comfort and sound just right. To be honest they didn’t get much use since I couldn’t nail either. I’ve played around with the included S-Cush and G-Cush pads but both had their shortcomings for me.
The G-Cush sounded decent but the comfort for me was awful. Couldn’t get them to sit comfortably, my ears kept sliding so that the edge of my ear would touch the cold metal grill and the rest would rest against one side of the cup. Also since I wear glasses they didn’t want to seal well. I even tried washing them in warm water with shampoo/conditioner to try and soften them up, which helped a little but not enough.
As for the S-Cush the comfort was better but the thickness of the pad made the sound suffer with the highs getting muffled and mids sounding a little thin in some songs. The bass was punchy but overall on balance with the highs and mids. An decent experience overall if you like a more flat sound signature but for me personally it always felt like there was more there but you missed out on it due to the pad.
Finally I ordered wang_yifei’s L-Cush pads. They provided a decent in between for me and were what stayed on the headphones since. An interesting 3 layer design; the exterior layers consisting of firmer and denser foam with a softer and more open foam sandwitched in between. The pads came with foam disks to insert in the middle of the pad and provide some cushion against the speaker grill. There is very little difference in sound while having it in or not. Definitely recommend having it in since the cold metal grill isn’t exactly comfortable. The sound is quite similar to G-Cush pads however in this case they provide the best comfort for me personally is the best of the 3 pads. The highs and mids are nice and clear and the bass is slightly more present compared to the S-Cush pads. The pads are on-ear however the do cover the entire ear in my case and provide a little bit of a seal. If the provided pads don’t quite work for you these are an easy recommendation in my opinion.
Also after watching Zeo’s review I’ve finally tried unscrewing the backs of the cups and they do sound better without anything on the back; fully open. Also another thing to try is use large over ear pads. I’ve tried it with some pads I had for my Fidelio X2s and sandwiched them between the cups and my head since there is no way to mount them unless you’d modify the inner ring to fit large pads. Honestly this might be the definitive way to mod them. The bass gets a lot more punchy and drowns out some of the harsh highs that these drivers push out.
Overall I grabbed them for £38.29 total so not a huge loss and I listen to them from time to time since they do sound good for acoustic/vocal heavy songs. If you can get them cheap and want to something to tinker with they are definitely good for that.
I actually used the black padding on the back just to keep the dust out (not much of sound difference) but ya they are a fun pair to experiment on with pads a foam and all that kind of thing, they might not be “end game” but you can certainly make them halfway decent and even pretty good if you manage to tune them.
And since they are so easy to take apart you have a really fun time without having to worry about any real damage you might do, worst thing you can do is you over paid for a handband, a cable, pads, and other random shit.
I’ll try the L-cush pads, see if they get any better for me
Hi everyone. I registered here just to reply this thread. I watched the video zeos made. It seems likely that drivers are 50mm and the 40mm on the “name” of the headphone is just a typo. Zeos did note that driver looks big for 40mm and to me the distance from driver to the cup edge looks same as on oh2000. Driver also looks the same. Internal wiring is different color.
I’ve written about oh2000 on head-fi but since there is no dedicated thread there I’ll write my impressions here and talk about driver transplant I did.
I want go into build quality. It’s excellent like Zeos said. He was very comprehensive. 
One thing I noticed that I think was not mentioned is that L - R indicators on the rodblocks are on “wrong” sides. On grado headphones rod goes behind the headband but on the chi-fi headphone it is at front.
I also agree with Zeos about how these sound stock. Ice pick through eardrum sounds like a soothing alternative compared to listening stock oh2000.
This is a measurement I made. Minidsp ears and even most of the more expensive measuring devices are notoriously bad at measuring higher frequencies so this is in no way accurate measurement. But it is accurate enough to show oh2000 is excessively bright headphone. I put Beyerdynamic DT1990 there for comparison as it also has elevated treble.
As stock there is not much to be said about OH2000.
Thats about it.
I tried some modifications but I did not get them to sound like I would have wanted. I think it’s because of the bad driver. Many headphones use drivers that look the same, v-moda, Somic, Ollo, and TDK come to mind. I have fiddled with Ollo S4 and Oh2000 driver side by side and I can say for 100% that they’re different drivers that look the same. The way diapragm reacts to touching is very different. Ollo’s driver is a lot more responsive and will dent if poked. OH2000 driver is just a piece of thick plastic that does not move much if pushed.
So the driver needed to go. As replacement I chose Peerless HPD-50N25PR00-32. It’s a tried and true driver used in original Kennerton Vali, Aurorus Audio: Borealis & Australis and in Hyland Headphones. Drivers cost about $10 for a single unit at parts-express and digikey. I thought if it’s good enough for a $1000 headphone it should be good enough for this $50 project.
By now everyone knows how to open the headphones. Just twist them open like bottle caps. Driver came off just by pushing it. Solder points were protected with some black goo. I recommend cutting the wire high enough so it’s clean. I don’t think soldering that goo on a new driver is a good idea. There is a small + on peerless driver. Thats where you want to solder the red wire.
After you have soldered the new driver, put it in place. It should sit firmly. Now things get bit tricky. Edge of the driver is too thick so the front cover won’t fit back anymore. You need to cut of some of the plastic edge.
I used a small carpet knive blade. What ever you use just make sure it is VERY sharp. It looks bit risky but with a sharp blade it is easier than it looks. Driver is stable in the housing so you should get a good grip. Just don’t wave the blade over the driver. The magnet is very powerfull. After you’ve cut enough to fit the driver cover back in you can glue the driver in place from the inside. Of course if you are certain you won’t break the driver you might as well glue it before cutting the edge. I did not even glue the driver so this step is optional. Now the hard stuff is done!
For me oh2000 is a bit loose. Headband is too wiggly for those heavy metal cups. I bend the headband quite a bit to get a tighter fit. It seems the headband is pretty much undestructable.
I tried some modifications but I ended up not using any. I did leave the cups open though. There was not much measurable difference in frequency response but I think without the back covers things just sound bigger somehow. I might make a permeable back grille from a sieve or something. I use the G cushions only. Small ones still sound bad.
Here is the frequency response. Sennheiser HD6XX is there for reference. Notice how basslight HD6XX looks on the measurement. That will give a better understanding to the bass level of OH2000.
What we have here now is a very unique headphone. It has bass that no Grado can match. It does not sound as airy as Grado’s do. Partially it is because of lesser treble quantity but I think it is also because this paper dome driver is very different from Grado drivers. Even though this is not as airy as grado it is still 100% open design with foam pads. It’s free of all sort of nasty reverbs and colorations. I think Timbre is excellent. What I love most about these is the “kick in the face” sort of sound. I sold my Focal Utopia last week and I’m allready missing the dynamic sound with slam. OH2000 does not hit as hard and of course these can’t match the speed of Utopias. These can’t spook unfocused listener like Utopia does. Still the incisive way these bombard listener with music is reminiscent of Utopia. Presentation of dynamics is also on a level I find stupid good considering what kind of money were talking here.
Overall I find very little to fault here:
So whats next? I was very surprised that these sound this good just with a driver transplant. I expected I would have to mod these extensively. Headband would need some sort of comfort mod. Should be easy to do. Traditional style earpads would be more comfortable but those will allmost certainly mess up the sound. I’ve tried some stuff to place the cushions in a angle. There is a noticeable improvement in soundstage debth when ears get further from the drivers. That is something definately worth experementing. I like the bass quantity but if someone likes to tone it down it is easy to do by partially blocking the big vent on drivers magnet. Maybe something like 10% reduction could be nice if that would tighten up the bass a tad. Maybe a piece of foam behind the driver would work best.
I hope someone else would try out the peerless drivers in these. Would be nice to hear other peoples impressions. Like people have said with the build quality of the headphones there is not much to loose and drivers are only $20.
To conclude this rather lengthy first post I want to clarify that I’m not a stranger to affordable headphones. I’ve been seriously into headphones since 2010-2011 and over the years I’ve had about 200 headphones. Most of them affordable. So I did not just go from Utopia to these and get surprised by backwards effect of diminishing returns 
Great post, welcome to the forum.
Wow im really happy that someone took up the mantle of heavily modding them, and that fact that it only cost you 20$ for the drivers is amazing.
I dont trust myself to enough to have the skill to do that kind of modding so im left with most pads, tuning materials etc, though i got them to an “OK” place, maybe some days ill get another pair and mod them with new drivers along with my 3rd set of KPH30I for a detachable cable mod, but until then im just happy to see folks really
I’ve been wanting to get a pair of the Openheart OH2000 and do a driver swap for a long time.
I ordered the OH2000’s off Aliexpress and the Peerless HPD-50N25PR00-32 drivers from DigiKey.
Stock, these things sound terribly bright. I listened to half a song or two before dismantling the thing and tossing the old drivers in the garbage.
I followed the excellent post by @Roderick to remove and fit the new Peerless drivers into the chassis. Soldering was easy, shaving the edge off the drivers was a little trickier but with some patience, I got the driver grille’s to fit back over.
With the G-cushions the headphones sound amazing. I do not have uber expensive headphones but I do have Meze 99 classics, Mid tier Grados, and some nice Shure headphones and these sound better than all the above. They are less comfortable than the Meze’s though, I had to bend the headband pretty hard to get it to clamp right. It still needs some work so I might actually get a new stiffer steel spring and redo the band sometime.
After enjoying the headphones for a few weeks, I wanted to improve them further. I ordered a pair of 100mm Brainwavz perforated ear pads from Amazon and designed a 3d printed adapter to fit. Before I had a chance to print the adapters, the earpads arrived. I attached the pads loosely to the headphone. Without the adapter the ear pads were about 32mm too big for the ear cups but I just wanted to see if they made a difference in terms of comfort and sound.
Comfortwise, the new pads were a big improvement. Soundwise, not so much. With the pads the bass was bloated and the mids sounded veiled. I tried using foam to increase the distance between my ear and the driver and nothing seemed to make a difference. The pads will be going back to Amazon and the G-cush will return. I’d love to try some pad rolling and see if I can improve the pads without compromising the sound quality of the headphones.
Overall, I’m really impressed with the driver transplant. It’s been a fun project and I hope to use my adapters at some point.
I just want to post an update here since this mod has unfortunately become a bit more difficult to perform. They’ve switched to a new driver at some point that’s glued in. Pushing it out didn’t work and it’s way too tight for isopropyl alcohol to get in there to dissolve the glue. I had to destructively remove the drivers with pliers. Not a huge deal if you aren’t planning on reusing the drivers but a bit wasteful if you’re the kind person that likes to reuse stuff. At least the magnets will come in handy at some point.
