Funny how different people will hear and interpret the same headphone. I like the SA5K a lot, but as one of a quartet of cans I keep within reach. I've never found the single headphone that does it all for me, and I switch around as my mood and music dictate.
That said, there are some qualities I particularly enjoy in the SA5K:
It's a bright, forward sound with a glittering upper register and great presence. The bass is both emphatic and contained. It doesn't contaminate the midrange with any creeping warmth, but it can be startling in its impact. As others have said, the presentation of detail can border on the microscopic at times, a quality magnified by the crispness of the sound. One can hear the edges of the notes. The soundstage is not large, but instrument placement and separation are exceptional. I notice this particularly in chamber music. I'm always conscious that this is a fast headphone, and this is reinforced by the separation of the notes that's part of the crispness I mentioned.
On the downside, the glitter and brilliance of the upper register can turn hard with some program material, not unpleasantly so, but audibly. The dominent highs and emphatic bass can overshadow the midrange. And that bass, while highly capable, is of short duration. There's very little decay to the sound, which can give it and on/off quality some find objectionable. Overall, the SA5K is probably the coldest sounding headphone I own. Even the K501s seem mellow in comparison. I would also describe the SA5K as sensitive to the source and amp. My PPA reinforces their coldness, brilliance, and speed in a way that's to my taste. Some might find it extreme.
On the question of neutrality, I don't think I'd describe them so. Someone (GS?) characterized the sound of the SA5K as "photo-realistic," and I would agree with that. Their floodlit clarity exaggerates as it illuminates. I think (and the Sale/Trade forum bears me out) that the Sonys are a polarizing headphone. Those of us who appreciate their qualities, like them extravagantly, and people who don't will find them anathema. No one seems neutral on the subject.
All this is IMO, of course.
BW
