These never really got a fair shake. Most audio sites and reviews that cover the new PX200s (the PX 200 IIs) will say that they were an improvement over the original. As far as design goes, they are correct. However, the original PX200s are much more enjoyable to listen to.
IMPORTANT: Many people have complained with the lack of bass of these. Get a pair of the PX200 IIs ear pads and put them on the original PX200s. The pads on the original 200s are thinner and do not seal very well. If you switch the pads out, and use the 200 IIs pads on the original 200s, you will get a much, much better seal. The bass went from being non existent to being fairly dominant and deep after I made the switch. I almost thought I was insane because the difference was that marked.
Anyway, the sound of the original PX200s is pretty balanced. I perceive the mids to be a bit recessed, but audible nonetheless. The highs are present and very smooth. The lows, with the new pads, are very present and very deep.
The overall sound signature is somewhat dark and airy, and very very smooth. In fact, I will say that the 200 IIs do better in clarity since their sound isn't as smooth; they are sharper and reveal more detail.
That said, the bass levels of the original 200s completely outdo the new versions. The new PX200s have almost no bass. It's there but very weak. It makes the overall sound cold and mechanical. I'll take overly smooth but well balanced to cold and mechanical any day.
Also, the ear cups are looser on the original 200s, and angling them just right takes a little more work, but it's not difficult, particularly with the bigger ear pads.
Soundstage is small and close together, what you'd expect from tiny headphones. Again, the PX200 IIs win out on this. However Clarity is good with the orignals, despite some of the more dense tracks losing some of the mid range separation. However, on nearly every song or track I've used them, I could still distinguish the mid range. Sound is very smooth across the board; highs are sweet and subdued rather than searing or piercing; the low end spreads out and has a lot of impact, and the mids are dark and somewhat unemphatic.
They sound remarkably like the HD 201s, and while those are the lowest end of the Sennheiser around ear phones, it's still impressive to capture that sort of sound quality in such a small package. The main difference is that the 201s have a much better soundstage. Another important difference is that the PX 200s are much easier to power and thus get high volumes with than the 201s.
Technically, they aren't as accurate sound wise or well designed as the 200 IIs, but the overall sound and balance is just more enjoyable. Plus, they have that basic dark and pleasant Sennheiser sound. You'll still hear most, if not all of the detail with these. One more con with the sound is that because it's so smooth, sometimes it feels like there's not a lot of impact.
If you can spot a pair, get em.
Edited by swaffleman - 5/6/12 at 2:28pm