I have to ask, if they have to be modded to be good, what is the point of buying them in the first place? I'm sure you could mod a lot of junk headphones into sounding acceptable, but you could also just buy a good pair to begin with.
I am not trying to sound hostile here. I am genuinely curious. I have never heard them, modded or stock, so I don't understand.
I believe the deal with the Fostex (I have a couple of modified pairs) is that they are a relatively inexpensive ($100) planar (I think its planar) headphone that can be easily made into a very good/excellent ($300-$500) headphone by spending a couple of bucks and a couple of hours on relatively easy modifications. Many people spend hours on their mods but the Fostex can be made very good in just a couple of hours and no special tools or skills are required. You've just got to want to do it.
here's my experience
these headphones out of the box sound terrible
tinny highs, no bass awful
after this fairly simple mod (a screwdriver and a couple hours)
they sound beautiful, sparkling detailed highs, tight bass, and midrange
to die for... theres no end of info out there for doing this
Fostex T50RP $107.00 (purchased in july)
Snap-on headband pad $17.00
electronics kit $20.00 (includes necessary materials, clay, felt, dynamat,etc...)
Alphapads from MrSpeakers $60.00
Mogami cabling, mini xlr jacks $20.00
Total $224.00
about half of what it would cost to buy the finished product