E-Mu MORPHEUS, Operation Manual

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Chapter 7: Preset Programming 75
PRESET PROGRAMMING
Triangle
Square
Sine
Sawtooth
Random
Inverted Sawtooth
Negative Amount
+ -
Sawtooth
LOW FREQUENCY OSCILLATORS (LFOs)
A Low Frequency Oscillator or LFO is simply a wave which repeats at a
slow rate. The Morpheus has two multi-wave LFOs for each of its 32
channels. The LFO waveforms are: Triangle, Sine, Square, Sawtooth,
and Random, which is a random “sample and hold” type of wave.
By examining the diagram of the LFO waveforms, you can see how the
LFO will affect a modulation destination. Suppose we are modulating
the pitch of an instrument. The sine wave looks smooth, and will
smoothly change the pitch. The square wave changes abruptly, and
will abruptly change the pitch from one pitch to another. The
sawtooth wave smoothly decreases, then abruptly changes back up.
The sound’s pitch will follow the same course. Controlling the pitch
of an instrument is an easy way to hear the effects of the LFO waves.
Like the Auxiliary Envelope, the LFOs can be routed to control any
realtime functions such as Pitch, Filter, Panning, or Volume. A com-
mon use for the LFO is to control the pitch of the sound (LFO
➡
Pitch). This effect is called vibrato and is an important performance
parameter. Many presets use this routing with the modulation wheel
controlling “how much” LFO modulation is applied. Another com-
mon effect, Tremolo, is created by controlling the volume of a sound
(LFO
➡
Volume) with the LFO.
Another use for the LFOs might be to add a slight bit of animation to
the sound by routing the LFO to control the filter. In this example, the
LFO amount would be set low, for a subtle effect.
When the amount of an LFO is a negative value, the LFO shape will be
inverted. For example, inverting the sawtooth wave produces a wave
that smoothly increases, then instantly resets down.