Thoughts on adding a Super tweeter .

I agree with the Tennis man on the overabundance of upper mid / lower treble energy. I base this assertion on my experience at CES / THE this year. Room after room had this characteristic. Even my own system has it to a degree, which annoyed me until I came home from CES. Then I turned on my system and it was a relief, because many (most?) of the rooms at the show had it far worse than my system does.

Also, keep in mind that a CD can not reproduce sounds above 20KHz. While it may theoretically be capable of producing "perfect sound" below this frequency, it has never been billed as having any capability above that point. So what you will be reproducing from a CD is not the musical content,but the residual digital noise that doesn't get filtered out by the player's filters. The better your player, the less of this there should be. Maybe if you're playing analog, there would be some content from the original event buried in the grooves.

Tvad - You are right of course, I forgot about the high-res media.

Cj - Your experience is what I think is supposed to happen w/supertweeters. The ultrasonic frequencies they reproduce aren't supposed to be heard by themselves, but by their interaction with other frequencies. The best analogy is if you play the same note on 2 guitar strings that are slightly out of tune, you will hear a low frequency wavering. This is called a beat frequency by acoustic engineers (and has nothing to do with the beat of the music). The supertweeters are supposed to produce audible results by modulating the rest of the frequency spectrum. In order to do this, though, they must be fed a signal that represents the ultrasonic content of the original musical event. This is not possible with Redbook, but is with hi-res and probably vinyl