In article , John Phillips
wrote:

[1] The DA models are all linear, but I have searched occasionally for
any evidence of non-linear effects arising from DA. These may be
audible if big enough. However the one mention I found was for
semiconductor-insulator (e.g. Silicon - Silicon Nitride) boundaries but
it provided no details and no references to follow up.

I'm familiar with nonlinear dielectric effects in terms of using bulk
material effects for things like frequency conversion in optonics devices
or Bragg cells. But the actual field levels and d/dt levels in such
applications tends to be high in order to get useful levels of
nonlinearity, and the materials chosen specifically for their nonlinear
properties.

I recall a colleague who used to build non-linear pulse lines for pulse
compression/peaking. He found some HV caps by a given maker that had truly
'awful' levels of dielectric nonlinearity when hit with multi-kV pulses.
His comment was that their slogan should be, "Don't take the **** out of
our capacitors: it spoils their usefulness!" ;- The point being that
most well-made caps simply didn't do this to such a level.


[2] Based on reported levels of audibility arising from frequency
response differences. However, recently I have become interested in the
human sensitivity to audio arrival time differences. Detectable
differences as reported seem to be smaller than implied by 20 kHz
hearing limits. I am looking out for more evidence on this.

I'd also be interested in that. However it does not surprise me. The
sensors for a given frequency band may have response interactions whose
timings have nothing to do with the physical limitation of the ability of
the upper HF sensors to detect 20kHz. The processes are distinct, I assume.

FWIW I have a recollection of reading about the above somewhere. I think
there may be a reference to it in one of the papers I refer to in the
articles on hearing on my Audio Misc pages. Can't recall, though, as I did
that some years ago...

Slainte,

Jim

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