While of only indirect relevance to "sound cards", a place has
to be found somewhere for a technology that took the PC world by
storm in the first half of 1999 - and this seems to be the most
appropriate. Derived from the original MPEG standard, MP3 - an
abbreviation of MPEG Audio Layer-3 - is one of three coding
schemes (Layer 1, Layer 2 and Layer 3) for the compression of
audio signals and uses an audio coding technique based on
psychoacoustics - the study of how the human brain perceives
sound - which has found that it simply can't process a lot of
the information the ear picks up. MP3 removes these redundant
and irrelevant parts of a sound signal. The MP3 standard divides
the frequency spectrum into 576 frequency bands and compresses
each band independently. The human ear is good at hearing mid-
range pitch noises, but no so good at high or low pitched
noises. These can be heard - but not well enough for the details
to be accurately distinguished. These bands can therefore be
heavily compressed without any