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In
order to reproduce sound faithfully, the Nyquist-Shannon sampling
theorem says that a sound can be perfectly reconstructed from its
samples if the sampling rate is at least twice the highest frequency
component of the signal. That's not the fundamental frequency of the
sound, it's the highest frequency component of the signal when its
spectrum is viewed in the frequency domain. The timbre
or difference in tone colour between a pure tone and e.g. the sound
from an organ, both with the same pitch and loudness, is that the organ
sound has a fundamental frequency and higher harmonics (multiples
of the fundamental frequency). The combination of, and amplitude of
harmonics is one factor that makes the timbre of a musical note from a
piano different from that of e.g. a flute or violin. The discussion in
the forum at the link suggests that CD recordings should be better than
analogue recordings on vinyl, considering that sampling is done at 44
kHz (twice the 22 kHz bandwidth allowed for audio signals). However
there are other factors involved, and another forum member suggests that
compression of the signal is involved when the pressing master is made
from the original master, and production CDs suffer in sound quality due
to this. Compression is necessary to reduce dynamic range (the
difference between the loudness of loud and soft sounds) so that
recordings can be listened to on earbuds rather than a hi-fi system, the
latter having greater dynamic range capacity. This compression of
dynamic range is distinct from the compression of the size of files to
reduce the storage space required on media. That compression is variable
and produces either lower quality/smaller file size or higher
quality/larger file size recordings, typically in the MP3 (for audio) or
MPEG (for video) file format. This is similar to the way bitmapped
images are compressed into a JPEG image file. Unlike MP£ files, sound
tracks on a normal CD aren't compressed and the data is in a raw format
that can be read by the electronics.A debate on the subject here.
