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Chapter 8: Pre Filter, Post Filter and Voice Mixes
ANDROMEDA A6 REFERENCE MANUAL 185
Modulator, using the sine waves of OSC 1 and OSC 2 is a good place to start because
sine waves have no harmonics. This will allow you to hear the Ring Modulator
produce a waveform with the least complexity.
Different results are obtained by using two square waves or two sawtooth waves as
these waveforms contain numerous harmonics which are also multiplied together.
Next try multiple waveforms in each VCO:
SAW plus TRI, SQR plus TRI, SQR plus SAW
or two square waves with different pulse widths. While you’re testing out different
pulse widths, you may also want to add pulse width modulation (press the
PWM
button and make changes to the assigned LFO’s square wave) to hear what happens.
You may also want to experiment with different VCO tunings – experiment with the
SEMITONE, CENTS and FINE knobs. Try modulating the frequency of a VCO (or both of
them) with a slow LFO or
ENV 1 (PITCH).
NOISE/EXTERNAL Control
The NOISE/EXTERNAL knob controls the initial level of three varieties of NOISE, the
level of the external
FILTER AUDIO INPUTS and the internal FILTER FEEDBACK. Each of
the four audio sources are selected in turn (or turned off) by repeatedly pressing the
input button; the current Noise/External source is shown by LEDs on the top panel
and in the display. Only one source can be selected at a time. But Filter Feedback is
on its own switch, and when this switch is on Feedback is added at a fixed amount to
the
NOISE/EXTERNAL input amplifier controlled by the NOISE/EXT knob.
NOISE
The A6 provides a single noise generator that is available to all voices. Noise is
produced by circuit that outputs nearly all audible frequencies at once, called
wideband audio. The result is an unpitched signal that sounds similar to the “static”
you hear on a radio when it’s tuned between two stations.
Noise is often used to simulate wind, thunder and explosions. When used subtly,
noise can embellish musical sounds created with the VCOs by adding breath effects
to brass and woodwinds, for example.
Noise is generated in three “colors”: white, pink and red. These are names that refer
to the frequency range of the noise signal. White noise (indicated by the
W LED on
the front panel) selects the entire range of noise at identical levels regardless of
frequency. White noise sounds the brightest and fullest of the three. Pink noise
(indicated by the
P LED) reduces the high frequencies and sounds less bright than
white noise. Red noise (the
R LED) has even more high end removed and sounds the
least bright of the three noise sources.
Pressing the button to the left of these LEDs switches among the three noise sources
plus
AUDIO EXT IN, described next.