Sorry to pick on you, but this is the piece of audio voodoo that irks me most of all.  There is no evidence I'm aware of that supports the idea that ultrasound has any effect whatsoever on human perception of anything.  This point is marketed to no end in the audiophile world, whether it's the supposed 100k frequency response of virgin vinyl, or the 50k response of SACD.  I believe it's 100% bunk.

If you doubt this, as many people do, try the experiment I used to prove it to myself:

1) Set up some good synthesizer software (e.g. SuperCollider, csound, PureData, etc.)
2) Generate pure sine tones of increasing frequency until you reach the point where you can't hear it (for me this point is just over 16k; for an older colleague of mine it's just under 14k) (warning: this revelation can be depressing)
3) Start cranking up the volume.  Your VUs will tell you it's there . . . your amp clipping lights will tell you it's there . . . your dog that runs screaming from the room will tell you it's there . . . your exploding tweeters will tell you it's there . . . but you won't hear it.  Ever.
4) Now that you've got this horrifyingly loud sound blasting throughout the room, live your life.  Watch some TV.  Listen to some music.  You won't notice anything.  Better yet, have someone else turn it off and on periodically, and you note when it's on.  You won't reliably be able to.

So . . . if an ungodly pure tone at, say, 18k has no impact on my senses at all, ain't *no way* that the "air" of a symphony at 30k will.  Until some unbiased A/B/X tests start showing up that prove otherwise, ultrasound is pointless in music.

I'd love to be proven wrong here.



Footnote: Yes, there's a valid argument for higher than 44.1k when recording, which involves the filters in A/D converter hardware.  There is no argument for it in the listener space.