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Re: [Phys-l] high frequency sounds



With a 44kHz sampling rate, one cycle of a 20 kHz sound wave will be
represented by only 2 numbers. So above 15kHz, the digital version of the
sound is not a very good 'analog'.

Why not? As per the sampling theorem, a 44kHz sampling rate allows one to "perfectly" recreate a waveform with frequency components up to 22kHz, well above most everyone's hearing range. Even with just 2 numbers.

But I admit to not knowing exactly how the playback electronics works. I'm assuming the CD is encoded at 44kHz regardless, and it is up to the electronics to create the analog interpolation. I think most recording is done at roughly 4x oversampling, but is downsampled/decimated for the CD.

Nuances (aka filter shapes/bandwidths), economics of chipsets, and audiophile arguments abound wrt these issues, and I admit I'm not up on all that, but are they enough to thwart the sampling theorem in its "first approximation?"


Stefan Jeglinski