Low Frequency Oscillators (Lfos) - E-Mu XK6Xtreme Keys Owner's Manual

Table of Contents

Low

Frequency

Oscillators

(LFOs)

LFO Tricks & Tips:

• The Random LFO wave is

truly random and is different

for each voice and layer.

• The Pattern (Pat) waveforms

will sound the same on

different layers and voices.

• Sine + Noise is very useful for

simulating trumpet and ﬂute

vibrato.

# When routing Hemi-quaver

to Pitch:

+38 = major scale

-38 = phrygian scale

+76 = whole tone scale

(+38) + (+76) = diminished

(two cords)

odd amount = S+H sound

Note: References to musical

intervals in the pattern LFO

shapes are with the LFO

routed to pitch and a

PatchCord amount of +38

   

Try combining the

Pattern LFOs, or controlling the

amount of one with another, or

combining them with the clock

divisors.

A Low Frequency Oscillator or LFO is simply a wave which repeats at a slow

rate. The XK-6 has two multi-wave LFOs for each channel. The LFO

waveforms are shown in the following illustration.

Ra nd o m

S i n e

2 5 % Pu l s e

Pa t : O c t a v e s

+ Octave

Pa t : N e e n e r

A #

S i n e + N o i se

By examining the diagram of the LFO waveforms, you can see how an LFO

affects a modulation destination. The shape of the waveform determines

the result. Suppose we are modulating the pitch of an instrument. The sine

wave looks smooth, and changes the pitch smoothly. The square wave

changes abruptly and abruptly changes from one pitch to another. The

sawtooth wave increases smoothly, then changes back abruptly. The

sound's pitch follows 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, LFOs can be routed to control any real-time

function such as Pitch, Filter, Panning, or Volume. A common use for the

LFO is to control the pitch of the sound (LFO -> Pitch). This effect is called

vibrato and is an important performance effect. Many presets use this

routing with the modulation wheel controlling "how much" LFO

modulation is applied. Another common effect, Tremolo, is created by

controlling the volume of a sound with the LFO (LFO -> Volume).

Tr i a ng l e

S q u a re

1 6 % Pu l se

Pa t : Fi f t h+ O c ta v e

- Octave

S i ne 1 , 2

H e m i -q u a v e r

Programming Basics