Andy - there's too much to chew on here. But I can comment a little.No I do not think we hear tone above 20kHz. And I know that dogs do, and that Natasha hears bats talk and that fish sense 50kHz signals.
David Blackmer (DBX founder) and others have demonstrated that we can detect the presence or absence of 40kHz tones when riding on audio frequency tones. We also know from auditory research that impulses are processed in the time domain. In other words a crack or snap is perceived directly as a crack or snap with directional and other information that is not tonal. That impulse is further decoded in the brain, to "hear" its component frequencies much like a Fourier Transform,.
I am not claiming that a coherent speaker plays higher tonally than an incoherent speaker, merely that the temporal content is processed and "heard". Some individuals are quite sensitive and others completely insensitive to this temporal / impulse information. My suspicion is that Thiel customers probably fall in the time-sensitive camp more often than normal.
My upper limit is now 4kHz, dropping at 12dB/ octave. So I'm down more than 24dB at 20K. However, I can hear the artifacts of different digital filters working in the range of 20K and above. My point is that the sonic characteristic of tonality is only one aspect of hearing and does not define the limits of auditory input. In my opinion, which is in good company albeit in the distinct minority.
(A fascinating observation is when playing with the back-firing second speakers a couple weeks ago: I could tell more about the various digital filters when playing the filter changes from the rear-firing speakers than when playing from the front-firing speakers. Also, polarity reverse of the rear-firing speakers did not change my ability to perceive which filter was in use. Go figure!)
Perhaps more to the point in speaker design, we at Thiel systematically discovered the auditory - emotional - holistic importance of accurate phase/time component in the musical signal. In particular, the absence of phase distortion lifts a mental veil which allows the audio brain to see more thoroughly to the essence of the sound. Sound processing is processor (brain) intensive, and removing the big demand of reconstructing time/phase information in a scrambled signal frees the brainpower to perceive other subtleties of the signal (in my considered opinion.) That effect might be called psychoacoustic, but it is nonetheless real given the fact of auditory processing system limitation.
My present work on lifting a veil for the Renaissance revitalizations makes use of this insight. I would not even hear the veil on a higher order system. But I can on this minimum phase system, and I can hear considerable detail and make and test constructive hypothesis, all well below intelligibility on a high order system.
David Blackmer (DBX founder) and others have demonstrated that we can detect the presence or absence of 40kHz tones when riding on audio frequency tones. We also know from auditory research that impulses are processed in the time domain. In other words a crack or snap is perceived directly as a crack or snap with directional and other information that is not tonal. That impulse is further decoded in the brain, to "hear" its component frequencies much like a Fourier Transform,.
I am not claiming that a coherent speaker plays higher tonally than an incoherent speaker, merely that the temporal content is processed and "heard". Some individuals are quite sensitive and others completely insensitive to this temporal / impulse information. My suspicion is that Thiel customers probably fall in the time-sensitive camp more often than normal.
My upper limit is now 4kHz, dropping at 12dB/ octave. So I'm down more than 24dB at 20K. However, I can hear the artifacts of different digital filters working in the range of 20K and above. My point is that the sonic characteristic of tonality is only one aspect of hearing and does not define the limits of auditory input. In my opinion, which is in good company albeit in the distinct minority.
(A fascinating observation is when playing with the back-firing second speakers a couple weeks ago: I could tell more about the various digital filters when playing the filter changes from the rear-firing speakers than when playing from the front-firing speakers. Also, polarity reverse of the rear-firing speakers did not change my ability to perceive which filter was in use. Go figure!)
Perhaps more to the point in speaker design, we at Thiel systematically discovered the auditory - emotional - holistic importance of accurate phase/time component in the musical signal. In particular, the absence of phase distortion lifts a mental veil which allows the audio brain to see more thoroughly to the essence of the sound. Sound processing is processor (brain) intensive, and removing the big demand of reconstructing time/phase information in a scrambled signal frees the brainpower to perceive other subtleties of the signal (in my considered opinion.) That effect might be called psychoacoustic, but it is nonetheless real given the fact of auditory processing system limitation.
My present work on lifting a veil for the Renaissance revitalizations makes use of this insight. I would not even hear the veil on a higher order system. But I can on this minimum phase system, and I can hear considerable detail and make and test constructive hypothesis, all well below intelligibility on a high order system.