A thread about custom IEM's was going off-topic into the hypersonic effect (inaudible frequencies at 20kHz+), I couldn't find any recent or alive threads on the issue so I created a new one. Feel free to voice your opinions a la "it's just marketing hype and pseudo-scientific nonsense, what's the point when you can't even hear it..?" or "it's the apotheostic life-blood of hi-fi, where's my portable SACD player..?" et cetera..... The topic of discussion was mainly revolving around IEM's that extend to 26kHz, and academic essays like this one -> http://jn.physiology.org/content/83/6/3548.full Whatever your take on hypersonics is, it sure is fun to read essays like that one, and part of me wonders if there is a cult following of hypersonic enthusiasts out there in their respective Hi-Fi rooms, and if that niche will ever transgress into portable audio.