Disclaimer: This is not an official Beyerdynamic product, nor is this a DIY guide.

"A truly high end audiophile grade headset," this is a statement that I sadly have not been able to make about any product. They never seem to have all of the features that I want in a high end headset, and they never have what they need to be a high end audiophile grade headset. Most have fairly low resistances which I don't think could be justified for the typical audiophile desktop home setup. Quite a few have semi- or fully- open backed designs, which for me can't be justified with use of a microphone that is next to your face (unless if it has great ambient noise cancellation and your volume is perhaps low with say a semi- and not fully- open backed headphones). And none of them have the detailed sound quality of a T1 or HD800 (none of them are even in that price range), at best there are perhaps headsets that are are par with the Beyerdynamic DT line in terms of detailed sound. And the last thing that makes a pair of headphones into an actual headset: the mic. I'd say that the majority of microphones that are integrated with audiophile grade headsets generally aren't that good, granted when gaming I don't necessarily care how I sound to my friends so long as they can understand me, but I'd still like for there to be a standard set in place for headset mics because I don't like hearing my friends voices being carried as fuzz audio and I know that as fellow audiophiles they think the same thing about my voice. I don't like having add-on solutions like modmic either because I don't like having a second cable and it makes me mad having a magnet so close to my drivers (even if the distortion is very minimal, I already pay top dollar just to not hear that) when they could have designed the modmic to have a clasp or ball-in-socket method of attachment.
 
Basically, the full list of requirements that I have are:

1. High impedance (600 ohms if possible)
2. No noise leakage
   1. Closed-backed
   2. An adequate seal
      1. Adequate clamping pressure/force
      2. Non-perforated leather earpads
3. Detailed sounding high end drivers with a fairly neutral sound signature
4. A decent sounding mic
5. Mic has to pickup sound below 50Hz to catch all of the overtones of my deep voice
6. No separate mic cable (other that the two heads at the ends)
7. No magnetic attachment mics (I don't want magnets interfering with the drivers; e.g. ModMic)
8. An overall comfortable design
   1. All non-synthetic materials are preferred 
   2. Soft, but dense viscoelastic foams are preferred (e.g. memory foam possibly with silica gel)

Since nothing like this was out there I decided that I'd just create my own:



































 
Here's the full list of components used (I ordered most of the individual parts directly from Beyerdynamic Germany): 
 

1. A used Custom One Pro (for it's housing, jack, and metal band)
2. Black Leather Beyerdynamic HS 800 aviator headband
3. Black Leather Beyerdynamic HS 800 viscoelastic (memory + gel) foam earpads (that are not perforated)
4. Gen.1 T1 drivers (there was no Gen.2 at the time)
5. T1 ironing bracket and sliding kit (mostly for aesthetics, but it is a little bit more comfortable since the ear cups have greater rotation)
6. Beyerdynamic COP Headset Gear Custom One Pro Microphone cable
7. A few other cables for when I am using my desktop mic or smart phone
8. A Custom Cans Mass Loading and damping kit (Butyl petty resin + aluminum foil; e.g. Dynamat)
9. And a decent 3 channel (R+, R-, and an additional ground) wire cable to route in between the ear cups (I enlarged the wholes to make it fit and sealed it with a rubber gasket)

 
These mods weren't done with an absent mind. I understood that since the original T1 driver was designed for a semi-open backed housing, placing the drivers into this housing caused the bass drop significantly. Two things were done to fine tune the bass to increase it back to it's original levels while still being in the COP housing. First, I enlarged the bassports (not too much though, otherwise this would basically still be a semi-open backed headphone) and set the bassport to position 4. Second, those leather earpads are non-perforated memory foam pads that help create a better seal, doing this significantly increases the bass relative to the rest of the sound. After that it was just a matter of fine tuning the bassports until the bass was perfect. This headset actually is dampened, and sounds a lot better than my undampened T1. I found this dynamat kit to be the best dampening for this particular build as nothing else work sonically and because of the tight fit: 




My impressions on the sound of this compared to a regular T1 is that the Custom T1 Pro sounds quite a bit louder, it has a significant more amount of isolation, the soundstage is quite a bit less (that's the cost of having them be closed-backed), and they more or less actually sound the same other than the hot treble spikes not being present in the Custom T1. Also, I'd say that overall out of the two this one is far more comfortable.

Since this isn't a DIY guide or anything I won't be posting on how to make this in the comments. I won't be making a DIY thread either unless if you guys were REALLY interested since that would take up quite a bit of my time. If you have any questions, requests, criticisms, or helpful advice about these headphones, then feel free to join the discussion down below.

Nice, looks mighty fine. Kudos.

I had a great discussion addressing many of the criticisms against this over at the linustechtips forum: http://linustechtips.com/main/topic/465632-beyerdynamic-custom-t1-pro-headset/#entry6250780

I'm astonished how much work you must have invested...
You reused the T1 frame, just substituting the cups and the headband, correct? Plus other pads of course...
Did you transfer the COP cabling (between the cups)? I'd guess that might be the reason to use the COP headband.
 
The new DT1770 did not fit your bill (I don't know wether the COP microphone could be used with that though)? Why was a high impedance so important to you?

plakat said:

  I'm astonished how much work you must have invested...
You reused the T1 frame, just substituting the cups and the headband, correct? Plus other pads of course...
Did you transfer the COP cabling (between the cups)? I'd guess that might be the reason to use the COP headband.
 
The new DT1770 did not fit your bill (I don't know wether the COP microphone could be used with that though)? Why was a high impedance so important to you?

Click to expand...

That's not quite right. I'll give you the full list of components used (I ordered most of the individual parts directly from Beyerdynamic Germany): 
 

1. A used Custom One Pro (for it's housing, jack, and metal band)
2. Black Leather Beyerdynamic HS 800 aviator headband
3. Black Leather Beyerdynamic HS 800 viscoelastic (memory) foam earpads (that are not perforated)
4. Gen.1 T1 drivers (there was no Gen.2 at the time)
5. T1 ironing bracket and sliding kit (mostly for aesthetics, but it is a little bit more comfortable since the ear cups have greater rotation)
6. Beyerdynamic COP Headset Gear Custom One Pro Microphone cable
7. A few other cables when I am using my desktop mic or smart phone
8. A Custom Cans Mass Loading and damping kit
9. And a decent 3 channel (R+, R-, and an additional ground) wire cable to route in between the ear cups (I enlarged the wholes to make it fit and sealed it with a rubber gasket)

 
In total, I'd say that it only cost me around ~$700 to make (aside from my tools and resources).
 
I guess there could be a small enough female 3.5mm to mini female xlr adapter out there to work without being too clunky, but I made this long before I even knew that there was going to be a DT1770. In any case, this headphone would still have to be better, so I probably won't ever be getting a DT1770 (though I might order me a it's metal band for that nice clamping force that it's got).
 
I guess 600 ohms probably doesn't matter that much, much like 16 bit vs 24 bit audio. Or at least that's what I'd say normally. Once you add all these small unnoticeable things together, then you finally get that last 1-5% improvement to your audio which is noticeable. And once you're used to that you can never go back, or at least not too far back. I mean, I'd have to say that the HD 800 sounds pretty great at 300 ohm, better than an undampened T1 does in my opinion. I might be going off on a tangent, but I feel like my perceived soundstage of the HD 800 was being a bit overcompensated, and the treble spikes of the HD 800 were hot just like an undampened T1. I've never tried a dampened HD 800, but I really like where the soundstage and treble are at for my dampened Custom T1 (I've tried an undampened regular T1 too, but I prefer mine).  

Awesome stuff man! this was my transplant a couple years ago...
http://www.head-fi.org/t/656644/ortho-transplant-fostex-t50rp-drivers-into-a-beyerdynamic-custom-one-pro

armaegis said:

Awesome stuff man! this was my transplant a couple years ago...
http://www.head-fi.org/t/656644/ortho-transplant-fostex-t50rp-drivers-into-a-beyerdynamic-custom-one-pro

Click to expand...

That's a lot crazier than what I did. I'm amazed that you pulled that off given the compact space within the COP earcup. I've always wanted to do a build with the TH-900. Since that's also a fostex do you think it could work?

I was super worried when I realized I should have offset the mounting holes for the driver. Fortunately, it still fit (literally by a hair). I didn't fiddle with too many damping arrangements given how tight the fit was and I didn't want to risk damage. I went with my standard rear acoustic foam and front felt arrangement and left it at that.
 
What drivers do you want to put into the TH-900? If anything, I'd try mangling a TH-600 first before touching the expensive 900. You could also look for a used Denon D2/5/7000 which I believe is more or less the same headband assembly.

armaegis said:

I was super worried when I realized I should have offset the mounting holes for the driver. Fortunately, it still fit (literally by a hair). I didn't fiddle with too many damping arrangements given how tight the fit was and I didn't want to risk damage. I went with my standard rear acoustic foam and front felt arrangement and left it at that.

What drivers do you want to put into the TH-900? If anything, I'd try mangling a TH-600 first before touching the expensive 900. You could also look for a used Denon D2/5/7000 which I believe is more or less the same headband assembly.

Click to expand...

I was actually thinking of putting the TH-900 into the custom one pro, dampen it with dynamat and I'd be able to control the TH-900's overwhelming bass with the COP's bassports.

How much do the drivers cost?
 
I believe the TH900 shares the same driver as the D5000/7000, so finding a used D5k might be slightly cheaper.

armaegis said:

How much do the drivers cost?

I believe the TH900 shares the same driver as the D5000/7000, so finding a used D5k might be slightly cheaper.

Click to expand...

I'm not sure, I'd have to contact Fostex to find out.

Fostex claims that it's a new driver, but I can't help but believe that it still shares many similarities with the d2000/5000/7000 drivers. They all are neodymium dynamic drivers that share the same sized diaphragm and ohms. The most important part of the TH-900 drivers for me are that they have a telsa measurement of 1.5, and I'm not sure if that's the same for the denon's.

I remember reading that the D5000 and 7000 share the same drivers, and then elsewhere I read the TH900 shares drivers with the D7000. This is all hearsay and fuzzy memory though.

armaegis said:

I remember reading that the D5000 and 7000 share the same drivers, and then elsewhere I read the TH900 shares drivers with the D7000. This is all hearsay and fuzzy memory though.

Click to expand...

I've been hearing the same stuff, that's what worries me since I'm not sure. Although, most of the heresay that I heard was that Fostex worked with Denon to build their headphones before doing their own.

Absolutely they did. The pedigree from the headband is quite obvious.