2009

CommentsWaveform
Well suited for vibrato effectsTriangle
Well suited for helicopter and space gun sounds. Intense
modulations of the oscillator frequencies with a negative (inverse)
sawtooth wave lead to “bubbling” sounds. Intense sawtooth
modulations of lowpass filter cutoff and resonance create rhythmic
effects. The waveform can also be inverted, resulting in a different
start point for the modulation cycle.
Sawtooth
Use of the rectangular waves will periodically switch the LFO
between two values. The Rectangle Unipolar wave switches between
a positive value and 0. The Rectangle Bipolar wave switches between
a positive and a negative value set to the same amount above/below
0.
An interesting effect you may want to try out is achieved by
modulating pitch with a suitable modulation intensity that leads
to an interval of a fifth. Choose the upper rectangular wave to do
this.
Rectangle
The two S & H waveform settings of the LFOs output random values.
A random value is selected at regular intervals, as defined by the
LFO rate. The S & H waveform steps between randomized values
(rapid switches between values). The S & H Lag setting, smooths
the random waveform, resulting in fluid changes to values.
The term Sample & Hold (S & H) refers to the procedure of taking
samples from a noise signal at regular intervals. The values of these
samples are then held until the next sample is taken.
Tip: A random modulation of pitch leads to an effect commonly
referred to as a random pitch pattern generator or sample and hold.
Try using very high notes, at very high rates and high
intensities—you’ll recognize this well-known effect from hundreds
of science fiction movies!
Sample & Hold
Can be used for chaotic modulations, but it is principally of use in
conjunction with the LFO envelope function—where you would
introduce a brief modulation at some point in the note phase—for
example, to introduce breath in a brass emulation, or to control an
organ key click or piano hammer noise. The random nature of the
noise waveform means that such modulations would vary slightly
each time.
Filtered Noise
Using the Sculpture LFO Envelope Generator
The LFOs feature a simple envelope generator, which is used to control the time it takes
for the LFO modulation to fade in or fade out. At its center position, which can be accessed
by clicking the middle mark, the modulation intensity is static—in other words, no fade
in or fade out will occur.
To set the LFO modulation fade time
µ
Choose a positive Envelope knob value to fade in the modulation.
The higher the value, the longer the delay time is.
356 Chapter 14 Sculpture