Well, I've had these for a few months. Since I have these Shure SRH940s and Sennheiser HD650s, I've had a chance to extensively compare them with equalization, etc. Obviously they're quite different headphones so it's hard to directly compare, but there are some interesting things to note.
The most interesting thing to me is that I still find the Shure SRH940's to literally blow away the HD650 in everything from mids to highs, and especially highs. The HD650 quite literally sounds a league below the SRH940 when switching back to it, even when the HD650's treble is EQed up front like the SRH940. The SRH940 sounds more detailed and simply better quality than the HD650 across the range, EXCEPT for bass. Bass and lower mids is one area where the HD650 dominates easily. The SRH940 lacks the ability to hold a strong impactful bass waveform I think, even though it is not bad at all.
My only concern with the SRH940 was actually a feeling of graininess that I didn't hear with the HD650. I just realized this is compression artifacts of some poorly compressed songs I was listening to. After listening to properly compressed high bitrate versions of them, the SRH940 has distanced itself even further in quality above my HD650, while the HD650 sounds more or less the same with both bitrates. I don't know, maybe my amp is bad or something for my HD650, but in any case this is what I'm hearing.
As a result, listening to music on my SRH940, then back to the HD650, the HD650 sounds like going back to lower-fi headphones, except for bass centric songs. The articulation of the highs and detail in general on the HD650 is good of course, but I'm finding the SRH940 just twice as good in every direct comparison.
I still listen to the HD650 for movies and bassy songs, and it's quite nice in its ability to be 100% nonfatiguing and superior physical comfort. But as far as high fidelity is concerned... I have to say the SRH940 wins by a huge margin.
Edited by ac500 - 11/7/11 at 8:46am