And I had thought my purchase of the Sony CD2000 was the end-all to my quest for a super-comfy pair of headphones that are unamped-portable-player-friendly AND sound great (not just good). Unfortunately, such a headphone that fully meets my criteria doesn't exist at all. Given great sound quality, I had to settle for either a terribly uncomfy pair of headphones that are portable-audio-friendly, or a super-comfy pair that requires a huge, ultra-expensive amp just to get any sound at all whatsoever. Also, if super-comfy and portable-friendly are both what I'm after, I would have to settle for relatively crappy sound. And, as it turned out, the CD2000 is a mediocre imitator of those high-end Senns that are so acclaimed in the press.
Using a stock-cabled pair of the Sennheiser HD600 as a reference, I've found the CD2000's bass response to be a bit hollow: Whereas the HD600 delivers a reasonable balance between the low bass and the mid-bass, the CD2000 favours the low bass at the expense of the mid-bass. The mids on both phones are almost equal to each other, but the highs on the CD2000 are recessed and a bit grainy and undetailed compared to those of the HD600. The differences are slight, but clearly audible. Sure, the CD2000 is super-comfy, and are efficient enough for use with most portable players - but those are the only two advantages that the CD2000 has to offer over the HD600. The HD600 isn't exactly uncomfy, but it puts a bit more pressure on my head than the CD2000. And though the HD600 can work at up to moderate volume levels with most portable players, a decent dedicated headphone amp is strongly recommended for its best sound quality.