The HD-Audio Challenge II

[ogs]

I am still quite confident that wide bandwidth makes a difference. No one (or extremely few) can hear above 17 to 20 kHz, but David's tale of intermodulation gives us a clue. Research has shown (I know I should reference this, but the closest I get at the moment is that the experiments were done in Japan many years ago) that listeners can discern a difference when tones above 20kHz are played in stereo and switched off and on, even if they can not hear the isolated tones. We're presumably talking about intermodulation that create harmonics in the audible range.
Also, Morten Lindberg of 2L says he needs extended frequency response above 22 kHz to record a proper impulse response without ringing.
So while we can not hear above 20 kHz, a wide frequency response is still useful.