"Trevor Wilson" wrote

I said nothing about audibility, or not. I was SPECIFICALLY referring to
the square wave capability of the different formats. I was careful enough
to specify the frequency too. MY ears are not under dicussion. The
relevant performance of the cited formats is.

Whilst it is possible to line up analogue tape machines to give a 30kHz
bandwidth, that is at the expense of in-band flatness and distortion. I've
seen the results of recording squarewaves on professional tape recorders,
and the results aint' pretty! In any case we are talking about expensive
studio machines here, the relevant comparison would be to 96 and 192kHz
sampled audio, which clearly has a far greater bandwidth.

As for vinyl, a typical minimum groove radius is 6cm. That means a linear
velocity of about 210 mm/sec. So the wavelength of a 60kHz signal is
..0035mm. What is the sidewall contact area of even the smallest stylus?

David.