Low Frequency Oscillators (Lfos); Shape - E-Mu PX-7 Owner's Manual

Low Frequency
Oscillators (LFOs)
224 E-MU Systems
A Low Frequency Oscillator or LFO, is simply a wave that repeats at a slow
speed. PX-7 has two LFOs per layer identified on the display as LFO1 and
LFO2.
An LFO can be routed to any real-time control destination using a
PatchCord. LFOs have a myriad of uses, some of which probably haven't
been thought of yet. The following examples show a few common uses.
• Control the pitch of the sound (LFO -> Pitch). This effect is called
"vibrato" and is an important performance tool. Many presets use this
routing with the modulation wheel controlling "how much" modula-
tion is applied.
• Create a "tremolo" effect by routing the LFO to control the volume
(LFO -> AmpVolume).
• Add a bit of animation to the sound by routing the LFO to control the
filter. Set the PatchCord amount low for a subtle effect.
The LFOs have five parameters: Shape, Sync, Rate, Delay and Variation.

Shape

LFO waveforms have different shapes. The shape of the waveform deter-
mines the effect of the LFO. LFOs have traditionally been used to add
vibrato or repeating movement to a sound. These new shapes offer a lot of
new programming possibilities.
L1
LFO1
If you modulate the pitch of an instrument, it's easy to visualize the shape
of the waveform. For example, the sine wave has a smooth, rolling shape
that changes the pitch smoothly. The square waveform changes between
two pitches abruptly. A sawtooth waveform increases the pitch smoothly,
then abruptly changes back down. The available waveforms are shown on
the following page.

Low Frequency Oscillators (LFOs)

SHAPE
sawtooth key sync
Preset Edit Menu
SYNC