The H2 setting is actually a combination of both bass / treble. 3 DB of each, if I remember correctly. H1 adds 3 DB of treble, while L1 is + 1.5 DB Bass and L2 is + 3 DB of Bass. O is flat.

I don’t know if I agree that it’s “just” the source material. My 80’s tend to bring this ‘S’ out as you describe. I agree that some recordings are most definitely worse, but I notice it on just about everything, if I listen for it. Symbol crashes can sound like one long ‘S’ on some recordings too. Prior to the Rotels, this problem was significantly worse. When I fired the Rotels up, I immediately noticed a change from the long ‘S’, to distinct sounds. Now after having them for a few weeks, I once again can detect the dreaded ‘S’. I’m afraid that if I plugged the speakers back into the HK 7200, I’d probably be disgusted.