Dd67000 crossover points?

@james633 . Thanks. I'll be looking into-for fun :)

@jc4659  from my post  AES preprint 3207 by Oohashi et al.  I didn't look into much detail - but it would be interesting for sure. As erik_squires mentioned, perhaps skin? 

@erik_squires . Interesting research--

 AES preprint 3207 by Oohashi et al. claims that reproduced sound above 26 kHz "induces activation of alpha-EEG (electroencephalogram) rhythms that persist in the absence of high frequency stimulation, and can affect perception of sound quality."

@erik_squires . More from same research-

Oohashi and his colleagues recorded gamelan to a bandwidth of 60 kHz, and played back the recording to listeners through a speaker system with an extra tweeter for the range above 26 kHz. This tweeter was driven by its own amplifier, and the 26 kHz electronic crossover before the amplifier used steep filters. The experimenters found that the listeners' EEGs and their subjective ratings of the sound quality were affected by whether this "ultra-tweeter" was on or off, even though the listeners explicitly denied that the reproduced sound was affected by the ultra-tweeter, and also denied, when presented with the ultrasonics alone, that any sound at all was being played.'

I distinctly remember a very unique "sensation" - that was more than sound- when going into a Jazz venue in Seattle back in early 80's.  Big venue, high ceilings, horns and cymbals full tilt. Exciting.  Perhaps Erik is right- skin picks up those ethereal sounds. Magic :)