[viggen]

Channel drops is a known, common problem. Clean the jack and plugs with alcohol or De-Oxit.

Sparkly highs? Treble and bass roll off fast. These are very mid centric with inverted U shape FR. It's certainly possible to improve FR without messing up the liquid smooth mids.

Thanks for the tip regarding how to ameliorate the channel drop out issue.  I will give it a try later.
 
Not sparkly highs but splashy highs.  Not quite noticeable at first, but my ears eventually picked up how the highs are bouncing around in the cups (noticeable by how tired/annoyed my ears eventually got after a few hours).
 
I have no intention of modding/dampen the headphones with clay or felt.  My philosophy with speakers is to keep the enclosure resonance "live" as though it's a guitar or violin body.  So, I like to keep the cups on the T50's live too.  But, would like to eliminate the splashiness with some diy diffuser.  But, they would have to be really small to fit in the headphone cups.  (yes I admit this does sound silly).

 

[nick n]

A diffuser is a great idea. Be sure to take picture when you get around to it.
Anything that soaks up the strays inside the cup is a good idea. Curious to see how you approach that.

 

[viggen]

  A diffuser is a great idea. Be sure to take picture when you get around to it.
Anything that soaks up the strays inside the cup is a good idea. Curious to see how you approach that.

 
I wonder if a small pc video card heatsink would do the trick?  Something made out of copper for warmer mechancial  resonance tuning but with lots of small tiny fins to diffuse the back waves.  But, not sure whether the fins will cause any ringing.

 

[Lohb]

Just got my Fostex T50RP's there and I'm going to burn-in to my brain their original sound for about a week rather than just diving in to the mod. Shouty mids and lack of bass/treble was my short impression when I tried them out last night.
I picked up the ready-made Mayflower mod kit for convenience so hope they use good modding materials.
 
Also picked up a 2.5-3 watts in to 50 ohms amp from Indeed company in Hong Kong from ebay to use the 50's on taps. Nice little amp and very portable for short trips off of mains which was what I needed.

Will also terminate some new cables at each can and I wonder is there such a thing you can buy as a "cable boot"....? Which is a bit of rubber that goes over the cable then fits inside/outside of the drilled hole on each side of the cups to seal it up nicely.

 

[hans030390]

 
I have no intention of modding/dampen the headphones with clay or felt.  My philosophy with speakers is to keep the enclosure resonance "live" as though it's a guitar or violin body.  So, I like to keep the cups on the T50's live too.  But, would like to eliminate the splashiness with some diy diffuser.  But, they would have to be really small to fit in the headphone cups.  (yes I admit this does sound silly).

 
That would make more sense if the T50RP's enclosure wasn't fairly cheap plastic that resonates easily vs. a speaker enclosure (generally wood). That, and neither speakers or headphones are instruments where you'd actually want resonance and such. Speakers/headphones should be as clean and controlled as possible.
 
Also, many basic diffuser ideas have already been proposed for the T50RP. I do not know of any particularly intricate or expensive solutions that have been publicly released.

 

[viggen]

I am not sure I am going to keep the cans yet.  I cracked the headphone open for the first time last night and didn't find a whole lot of space to work with.  My first order of attach, supposing that I will be keeping the headphone, is to apply violin lacquer to the inside of the cans which should alter the resonance property of the cheap plastic to something less plasticky and hopefully more organic sounding.
 
I did this with dacs before by applying the lacquer directly onto the circuit board and on their cheap abs housing, and the sound moved toward a smoother and less splashy midrange.  I also rewired the dac which is something tempting to do with the Fostex, but I retired from soldering (lazy cuz I am not good at it).
 
That said, the phones do sound better now than when I first got them.  I played it for 48 hrs straight.  I received the v-moda cable today, so I am able to listen to the headphone out of my headphone amp and not just out of my preamp's headphone output, and I replaced the Audioengine D3 dac with the Audio Sector NOS USB dac. 
 
MAYBE NOS dacs have better synergy with the Fostex.   Whatever the case, the sound is much better today.  Bass tones is weighty and sustaining.  I still wouldn't keep the phones if this is as good as it gets though.
 
One more thing.  I just noticed that if I lift part of the phones outwards to break the headphone cup's seal, the mid range becomes scary good like it's coming out of a compression horn speaker.  Basically, if I don't do anything, the cups are angled like this \--/.  And, by lifting the bottom of the cups a bit, the phones shoot straight into my ears like this |--|.  I lose some lower bass this way, but mid bass kicks much more precisely and everything else is much clearer.
 
Another way of describing how I achieve this effect, press the top of the headphone against your head with your index and ring fingers.  Then, lift the bottom of the headphone just slightly with your thumb outwards (away from your ears).  Let me know if this works for you guys. 
 
I am not sure how to mod the headphone to sustain this angle and openness though.
 
I just swapped ear pads between a DT990 pro and the Fostex T50rp.  Both cans are sounding better than before.  Or, it could just be psychological.  One thing I hated most about DT990's bass is it's overwhelming close to distorting the rest of the FR.  With the T50rp's pads, the DT990 sounds darker and there's less air.  But, the bass is controlled, no longer "fat".  Overall sound is more focused.  I don't have measurement equipment, but I'd hazard to guess the FR is less V but emphasis is in the lower mids.
 
As for the T50rp using the DT990's pads, the sound is more open, more air.  There's less bass but the bass is not more articulate, more acoustic.  Overall, it's an improvement over the stock pads.  However, with the stock pads and lifting the bottom with thumb, this "tweak" still sounds better.

 

[TMRaven]

Yes, I agree with this methodology completely. 
 
I violin lacquered my TV a couple months ago and I achieved a warm and seductive picture quality. 

 

[hans030390]

How well does it work on skin? Won't go into further details.

 

[viggen]

  Yes, I agree with this methodology completely. 
 
I violin lacquered my TV a couple months ago and I achieved a warm and seductive picture quality. 

That's a fair statement since I also predict the T50rps would sound dull and flat (though will measure better like a really good car audio system) after plastering them up with felt, wool/cotton and clay.

 

[oakleyguy89]

So i got the t50rps the way I like them. One only complaint is VERY LITTLE, not all female vocals are alittle too much at their peak. I was searching this thread and found you can add alittle something between the driver and ear under the 840 pads to cure that. Well I was doing some more research and someone claimed that cutting the driver felt out on the ear side made the headphones sound alot better. Well wouldnt that in my case make the treble even hotter? So my best bet would be just adding a little cotton between the driver and 840 pad?

 

[bluemonkeyflyer]

  So i got the t50rps the way I like them. One only complaint is VERY LITTLE, not all female vocals are alittle too much at their peak. I was searching this thread and found you can add alittle something between the driver and ear under the 840 pads to cure that. Well I was doing some more research and someone claimed that cutting the driver felt out on the ear side made the headphones sound alot better. Well wouldnt that in my case make the treble even hotter? So my best bet would be just adding a little cotton between the driver and 840 pad?

 Yes and Yes.
 
Try reversible mods, first, in any case. 
 
You could try a little cotton, fiberglass, polyfil, micropore tape, transpore tape, etc. over the ear side of the driver and under the 840 dust cover.
 
You could also try a "ring" of Paxmate/Silverstone around the ear side of the driver...don't cover the driver opening, though.

 

[oakleyguy89]

Great, Ill just stuff something in between then! Does removing the stock felt just make it louder?

 

[bluemonkeyflyer]

  Great, Ill just stuff something in between then! Does removing the stock felt just make it louder?

 
It won't make it louder. I cannot hear any difference but that may be my inability to hear anything over about 15 kHz.

 

[oakleyguy89]

   
It won't make it louder. I cannot hear any difference but that may be my inability to hear anything over about 15 kHz.

Okay, I'll just leave it then. I don't like my treble too piercing haha.

 

[Lohb]

I'm currently building up layer after layer of glossy black on my cups after sanding off the branding and filling in the single entry cable hole. Looking great vs the original matt finish. Will seal them off with 2-3 layers of clear lacquer as well....about 10 very thin layers over 3 days or so.
I'm planning on drilling at 45 degrees or so 2 direct cable entry ports on the external cups. Can the plastic cups snap/crack with slow machine drilling or is forced heated pointed metal through the exterior a better way to go with filing of the hole to remove any plastic melt in the hole ? Is there any re-purposed cable boot type thing I can use to seal the cups hole tightly from bass bleed ?