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Passeq Analog Code
®
Plug-in
M/S Stereophony
Our ability to identify the direction and distance of a sound source
is the essence of spatial hearing. The human ear can identify level
and time differences from ear to ear very precisely and use that
information to localize sound. At frequencies up to 1500 Hz the ear
analyzes basically time differences to localize sound, while above
this frequency it uses level differences.
Our hearing provides excellent conditions to apply room informa-
tion even to artificially generated sounds. Regardless of the defi-
ciencies and differences that loudspeakers and headphones might
present during playback, the human ear needs only the signals to
be codified in, at least, two channels, in order to be able to identify
time and level variations, which result in spatial hearing.
This sort of recording and playback that includes spatial informa-
tion is known as stereophony (from Greek stereos = solid or three-
dimensional). The resulting stereo image is called panorama.
Besides the two-channel stereophony there are several other
formats of stereophony. The common conception of „stereo“ as a
two-channel recording is thus incorrect.
Equally incorrect is the concept that the encoding of a stereo signal
is always done in a right and a left channel. This idea is based on
the fact that we have a right and a left ear and that all two-channel
recording and playback systems use the same right/left format. It
is also not true that all recordings are made with a microphone for
the left channel and a microphone for the right channel.
The differences between the most important microphone tech-
niques have much more to do with level and time differences. Due
to the advantages and disadvantages that each technique pro-
vides, more often than not they are combined during production
to achieve L/R playback.
M/S Basics
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