I have enjoyed these headphones for over a year now.

The measured bass distortion looks awful. My listening, however, does not match the measurements.

At an ear hurting level (90-100 dB) on bass-heavy movie soundtracks, I do not hear any distortion.

My experience is consistent with the following Japanese hobbyist's measurements (100 dB @ 1 kHz):

http://sonove.angry.jp/sony_MDR_MA900.html



2nd order harmonics are still a bit high but MUCH lower than Marv's measurements (you need to convert between % and dB scales).

2nd order harmonics in this lower octave should not be audible in a negative way.

Dist really only shoots up below 50Hz, but below that we got a lot of rolloff. Subjectively I didn't hear a lot of bass distortion, but I didn't hear any low bass either. It's all relative. LCD2 and Abyss kills it in terms of low bass quality (articulation, clarity, texture) though. HD800 kills it in terms of bass quality too.