In article , PeterN
wrote:

if they can't be heard, they can't be detected.

Absolutely false.

it's not false. it's common sense.

audio signals are heard. if they can't be heard, they do not matter. at
all.

They produce pressure waves.

so what? humans can't hear them.

In many cases the pressure waves can be sensed.

not many, and it's not reproduced by vinyl either, so it's irrelevant.

Strange how you forget
that when replying. I'm sure it's inadvertent

strange how you make up ****. actually it's not strange. its what you
do.