can you do a comparison with TH500RP ?
TH500RP is a troublesome one to comment on. Everyone thinks the cheaper T50RP is a great value for money planar magnetic headphones, and with the success Mr Speakers had with their dog mods, there was high hope that the TH500RP would sound magnificent, like a potential rival to the LCD2. However, I thought it was a bit of a let-down.
I found the main issue with TH500RP was the softened, artificially enriched, muddled mid-bass, which I believe is unnecessary. The tuning deviated from the studio-monitor like precision and clarity of T50RP, and ended up becoming somewhat mild, fluffy and casual, lacking in dynamics and power.
I have a feeling that Fostex may have listened too much to the casual user feedback, and tried to make the TH500RP sound "nice" by warming it up a bit and reducing the edginess. I found the treble and high mid still having that great transparency and linearity of the planar magnetic (without feeling too stiff and direct like Oppo), but the low mid felt like a vague ported subwoofer.
TH610 on the other hand feels a lot more direct and solid, with very wholesome low mid that makes every note substantial. The treble is not as crystal clear as the TH900, nor as thin and refined like TH500RP, but it does have a nice tone probably because of the wood cabinet. The bass in particular feels very well damped, so it has a nice initial kick, and doesn't echo around for a long time like TH500RP.
Because the TH610's housing and driver is well damped, I like the fact that every frequency from high to low sound consistent and uniform (i.e. nothing funny going on). I think the stereo imaging is solid and it gives a nice forward spherical projection (though not like HD800 etc). In comparison TH500RP sounds a bit too flat and lack the sense of forward distance. It gives you one of those in-your-head sound, which is nice and gentle and refined but unexciting.
Overall I like the TH610 because it has that multi-purpose feeling where I don't feel anything particularly bad or wrong about it. The dynamics is solid and big, so it's perfect not just for music but movies and games etc. I really have no complaints as a good pair of closed headphones.
TH500RP was too specific and had many annoying weaknesses as much as it had strengths. It's probably good for certain kind of instrumental music (like baroque harpsichord or violin etc..?) but you really either love it or hate it.
Also FYI, TH-X00 had too much cabinet reverberation, which bloated the bass and artificially enhance the sense of imaging, kind of like 3D surround sound effect. It's good for making some lame recordings turn more exciting, though I got fed up with it after a while.
In the end, TH500RP (and also TH-X00) does have some merits, but they were certainly not perfect and I ended up not using them much in the long run (same reason why I didn't buy TH900). I felt like I was listening to the characters of the headphones itself, rather than the actual music. TH610 felt like Fostex really did their homework to tidy up the tuning and made a pair of headphones that works well, without doing anything particularly special.
