Just modded mine, with dynamat and fiberloft, brings out the mids and also tightens up the bass with a little loss of soundstange width everything becomes more transparent without the resonances being present in the chamber, even after using a hifiman he-500 or a phillips x2 I don't feel these phones are inferior, and definitely superior if all are run unamped, I prefer these phones to the HD558 and my DT990 pro (too much treble and the mids are too recessed not to mention sub bass extension isn't as good imo). These phones are an absolute steal for 70~ USD.
Im looking for pad replacement wonder if other kinds of pads would change the sound, also wondering if senn momentum pads would fit.