8 SYNthESIS BaSICS
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with your playing style, for example to make the sound
brighter (filter envelope) or louder (amplifier envelope).
AD-envelope
a simpler form of envelope has attack and decay parame-
ters only, and is therefore called an ad-envelope. a version
of this has attack and release parameter, an a/r-envelope.
In effect, the ad-envelope behaves like an adSr-envelope
with Sustain set to 0 (see the picture at the top of this
page). this type of envelope, often with amount and inver-
sion controls, is suitable when you want to affect the start
of the sound only.
on the Nord Wave, the Modulation Envelope is of ad/r-
type. typically, it can be made to modulate the FM ampli-
tude or the pitch of oscillator 2, to create a different timbre
during the attack part of the sounds.
LFOs
an LFo is an oscillator, just like the ones that produce the
sound in a synthesizer, but with two main differences:
the LFo produces very low frequencies, most often
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below the hearing range (up to 20hz).
the LFo is not used to produce sound, instead it is
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connected to other modules to provide modulation of
parameters. If you for example route an LFo to pitch,
you get a vibrato. and if you route it to the amplifier of
an instrument you get a tremolo.
the three basic parameters for an LFo are Waveform, rate
(frequency) and amount:
the waveform determines the type of vibrato, for
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example “regular” (triangle or sine), ramp (sawtooth) or
random.
the rate determines the speed of the vibrato.
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the amount controls to what degree the LFo affects its
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destination.
