I did some further testing of the HP890, today (even if not too long, because it was the hottest day of the year over here, and I spent most of the day outside), because I wanted to confirm yesterday's results - so I can go a little more in depth, now:
Home use details: Well, first of all the HP890 still sounds really good to me.
One of the noticable differences between the HP890 and the DT531 is mid-bass: The DT531 will give a bass guitar more volume, but this might cover the bass drum a little. The HP890 sounds a little more flat or balanced in this area. On the other hand, the highs can sound a little more shrill or harsh on the HP890. A blend of the two would be just perfect for me on the old Marantz integrated amp. And I confirmed, that the DT531 is more efficient on higher impedance jacks (~ 11 o'clock on the pot for the DT531 seems to be the same volume as ~ 12 o'clock for the HP890 - and for the K501 it would be ~ 12:30).
Portable use details: Then I used the Panasonic SL-CT570A portable cdp: The DT531 sounds a little darker here, because of the lower impedance jack - and the HP890 a little brighter. For efficeny: At volume 10 (maximum), the HP890 will produce ~ 3 dB more volume (~ 93 dB; DT531: ~ 90 dB; K501: ~ 82 dB) - I checked that with the sound level meter using the same method & setup as last time in another thread. And again I'd like to have a blend of the two phones here.
For bus commuting - and other situations in which you'll have low frequency noise from outside - the DT531 might be preferable, because its stronger mid-bass will probably let you follow the bassline a little better. But if you prefer a brighter and a little more detailed presentation, the HP890 wins in this area. But I'd say both phones still sound quite good from a portable.
Comfort details: I still like the K501 best, because it's very lightweight and sticks on the head without much clamping force. Whereas the HP890 weighs heavier on my head and ears - and the DT531 is lightweight, but seems to have a little more clamping force.
All-in-all: I'd like the comfort of the K501 together with the HP890 bass and the DT531 highs, please!
I really don't know which one I'd chose myself, so I can't give a simple recommendation. Nevertheless, both the HP890 and the DT531 are cheaper than the K501 over here, so these two are the better buy in my opinion - and both are really good for the price. I just wish I didn't have to buy the HP890, now, but I guess I just have to. Can't resist...
Greetings from Munich!
Manfred / lini