Can somebody compare in depth side by side the HD660S2 with the HD800? thank you (i have hdv820 amp and hd800 , wonder if i need the new HD660S2 or not)
I've owned the 800 three times now, but don't currently have them. I had two of the silver 800 models, and most recently the newer black 800S. I can give you some general ideas how they compare, but can't go too in depth as I don't have an 800 anymore. I do have the S2.
Tonally the S2 is darker, with a pretty significant increase in bass presence and dynamic punch. From memory I don't know if the 800 can go down quite as low as the S2, but if it can it will be much softer sounding than the S2. The S2's bass is powerful, and goes really low.
Up top the 800 is brighter and thinner sounding. The S2's treble has very good presence, but isn't as forward as the 800's. It's also a bit more rounded sounding, not as hard. Smoother would probably be the best way to describe it. I personally found the 800's treble to be fatiguing, but don't find the S2's fatiguing at all.
The mids on the 800 are more forward. I loved the mids on the 800, even though I found them tonally a bit too cool. But they were very present, detailed, and expressive. The mids on the S2 sit farther back in comparison, and are tonally darker. They're also more dynamic and punchy. Vocals are cooler on the 800 but more forward.
Soundstage.... why bother! The 800 IMO is still the soundstage king. The S2 has a similar stage to the other 6 series sets. Good separation and placement, but the stage is small. This is an apples to elephants comparison.
I won't comment much on detail retrieval as I would want them both side by side to test. I do find the S2 to be the most detailed 6 series by a large margin. The jump in overall technical ability is quite large on the S2. Can it match the 800? I won't say without personal testing. But all my other impressions I'm confident in. I've logged MANY hours with my old 800s and know them quite well from an overall tonal perspective.
IMO the S2 would make an excellent complimentary set to the 800, being so tonally different. Also I think the 800 is the more relaxing listen, the S2 more immediate and aggressive (not too aggressive, just in comparison). But that's a subjective judgement call. If you have heard the 650, IMO the S2 is like a modernization of that unit. Similar tonality, but with significantly increased technical ability.