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Mixer:
Module, used for mixing several sound waves.
Amplifier:
Module, used for amplifying the weak synthesizer signals up to a loudspeaker
level.
Early synthesizer versions were volumineous boxes and cabinets, containing
a great number of analog modules and a lot of connecting cabling. Modern
integrated circuits and digital signal processing in software tools allowed mini-
mizing size and cabling of the synthesizer equipment.
MIDI
In order to interconnect different synthesizer modules or synthesizers we use
a standard synthesizer-language, called MIDI (Musical Instrument Digital
Interface).
MIDI-words may be understood as special codes. One of these codes is used
to control the pitch and another code controls the duration of a tone. A com-
puter may easily store code sequences in a MIDI-file and send the MIDI-file to
a synthesizer. The synthesizer equipment however must contain a so-called
sequencer to process MIDI-codes and to activate all synthesizer modules at
exactly the right moment.
Of course a sequencer may also be a computer program. Some computer
programs may even imitate or emulate a synthesizer. Complex sound modules
in a standard PC may already be equipped with a midi-interface (sequencer)
and a (more or less complex) synthesizer module.
