What did you mean by the hd25s sounding compressed or losing dynamics. Sorry, didn't understand what context this remark was in
Dynamic as in the difference of volume levels between the quiet and loud elements. With the HD 25-1, it almost sounds like DSP dynamic compression is being applied in that everything is quite upfront and - well impactful.
When I think of dynamic speaker setup, it could be a pair of Bowers & Wilkins connected to an excellent transport, DAC, pre-amp and power block. or similar... point being is there is a big trade-off in a little portable headset compared to an audiophile sound system (which can also be a higher end headphone with proper amp and source).
I may be out of my league in making such a remark, but a dynamic driver typically requires a clean and plentiful supply of powerful. The HD 25-1 driver is efficient and can be driven with a small amp. The drivers are probably as well engineered as can be for this type of use.
Someone else may be able to add or correct me here though. In my opinion, the HD 25-1 is almost perfect in its design for its professional applications, that of audio engineering and DJ work. It wasn't developed as a consumer headphone, but because of its attributes, it is one of the most enjoyable headphones for portable use (sans amp).
I am having a hard time selling mine, as I know there is very little out there that could replace it. Even though I'd be better off with a more full-sized can (DT880, DT770, HD650, K701) for studio work and composition, its also very convenient to have these at work, walking around, and DJing.
Its no wonder you see the HD 25-1 in the sigs of those who have much better sounding headphones - its that useful and sounds quite good, more than enough to be enjoyable.
The HD 25-1 is a desert island can if all you had were an iPod.