Just listened to some Fostex T50RPs today... WOW!
Jan 21, 2013 at 10:07 PM Post #9,871 of 11,346
Quote:
Could someone post a picture of how you are supposed to place the cotton in your headphones (as in how much are you supposed to pull it apart) I know it sounds like a newby question, but I have a feeling that for the past year that I have owned these headphones, I have been doing the cotton wrong. I have seen some pictures of people's cotton, but they weren't very clear, or seemed impossible to do with the cotton that I use, so sorry if I have actually missed a good picture.

http://www.head-fi.org/t/618659/fostex-t50rp-incremental-mods-and-measurements

You need dis
 
Jan 22, 2013 at 1:34 PM Post #9,872 of 11,346
just compared my simple modded T50RP (paxmate in the cup floor and plasticine in the baffle) with the HD650 and i´m missing the mids (something in the middle) abit.i´d certainly like to see the frequency curve of my T50RP but don´t know anyone here in germany i could send them too?
 
Jan 22, 2013 at 1:56 PM Post #9,874 of 11,346
i live in Braunschweig near Hannover. But i´ve sent the same question into the german hifi-forum.de if someone knew anyone with a dummy head to measure them.
 
 
Jan 23, 2013 at 10:12 AM Post #9,876 of 11,346
Quote:
The mod is very extensive. He picks the drivers, removes stock paper, saws through metal plates, mades wooden earcups no less than 10mm thick, and does custom damping, cup volume matching and earpad matching for each driver till +-2 dB.

I still think that uber-damping is an easier way to achieve flat sound from Fostex. But to get flat FR above 10 kHz, one would have to damp within driver anyway..

 
I think this guy is doing same thing with drivers ...
 
http://player.ru/showthread.php?t=58608&page=11
 
Jan 23, 2013 at 12:32 PM Post #9,880 of 11,346
Man, it's in Russia things are happening! Interesting to see the magnet bars and the damping. That frequency response sure is impressive, with less of a midrange dip than usual.



Midrange is doable with BMF's mods entirely, these seem to address the 11k resonance problem. Or it could be the quirk of measurement actually - all the RMAA measurements seem to be somewhat too flat after 10 kHz..

I think that could be done in less destructive way. But I'm not going into the drivers before I get another pair.
 
Jan 23, 2013 at 3:36 PM Post #9,882 of 11,346
That's a crazy dip between 8-9kHz... is it an actual drop or a measurement artifact?
 
Jan 24, 2013 at 10:19 AM Post #9,885 of 11,346
I'm not sure those chasms are artifacts. I got them in my readings (same setup as BMF's) too. I've attributed them to the "pinna notch" (discussed on page 5 of this graduate thesis), the product of destructive interference caused by the outer ear. The exact depth and location of the notch varies in my readings, but it's often there. 
 
Also, with some mods/certain pads, the effect is audible in log sweeps. YMMV.
 

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