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E-MU Systems
Programming Basics
Modulation
Modulation
To modulate means to dynamically change a parameter, whether it be the
volume (amplitude modulation), the pitch (frequency modulation), and so
on. Turning the volume control on your home stereo rapidly back and
forth is an example of amplitude modulation. To modulate something we
need a modulation source and a modulation destination. In this case, the
source is your hand turning the knob, and the destination is the volume
control. If we had a device that could turn the volume control automati-
cally, we would call that device a modulation source.
Turning the volume control back and forth on your home stereo is an example of
Amplitude Modulation.
Vintage Keys is designed so that each of the variable parameters, such as the
volume, has an initial setting which is changed by a modulation source.
Therefore in the case of volume, we have an initial volume that we can
change or modulate with a modulation source.
Two main kinds of modulation sources on Vintage Keys are
Envelope Gener-
ators
and
Low Frequency Oscillators.
In the example above, an envelope
generator could be routed to automatically turn the volume control as
programmed by the envelope. Or, a low frequency oscillator could be
routed to turn the volume up and down in a repeating fashion.
Positive modulation adds to the initial amount. Negative modulation
subtracts from the initial amount.
Summing Nodes
All the modulation inputs on Vintage Keys are summing nodes. This means
that you can connect as many modulation sources as you want to an input
(such as Pitch or AmpVol).
Modulation sources are simply added algebra-
ically— connecting two knobs one set to -100 and the other set to +100
yields a net value of zero.
Volume