Moog MESSENGER User Manual page 11

Unique for most sub-oscillators is the SUB WAVE control which allows you to vary the shape of the SUB
OSC from a clean triangle (adding pure bass weight with little extra harmonics) through variable pulse
width. Let's set the SUB WAVE to the same square shape as OSCILLATOR 1 (which on the SUB WAVE
control appears around 10:30).
Messenger contains two independent oscillators since layering two tones and having them play with each
other can create far richer sounds than with just a single oscillator. Raise OSC 2's level in the MIXER and
play with the OCTAVE and WAVESHAPE controls to hear the effect of layering tones on top of each other.
OSC 2 FREQ allows you to detune OSC 2 from OSC 1. You can create intervals such as fourths and fifths,
or just slightly detune OSC 2 from OSC 1 by moving OSC 2 FREQ just a little bit off from noon to create a
thick detuned sound full of beat frequencies and interference.
For this particular sound let's leave both OSC 1 WAVESHAPE and SUB WAVE set to square and raise the
level of OSC 1 in the MIXER to 3 o'clock and the level of the SUB OSC to noon. Adding in OSC 2 can create
a more complex sound, but let's leave OSC 2 LEVEL all the way down to use a more focused signal for this
Chicago house bass sound.
SHAPING A SOUND
We use the OSCILLATORS to build a sound and the MIXER to layer those sounds together. The output
of the MIXER then goes to the FILTER which allows us to sculpt our tone by removing frequencies. A
lowpass filter like the traditional Moog ladder filter removes high frequencies and is perfect for carving
our buzzy square waves into a thick bass tone.
As you move the CUTOFF knob counterclockwise listen as high frequencies get progressively removed.
Play with the MODE switch and move CUTOFF to hear how each filter mode affects the sound differently–
lowpass filters darken the sound, the highpass filter thins the sound out, and the bandpass filter allows
only a narrow range of frequencies through.
Playing with CUTOFF is a nice way to shape a static sound, but our sound design possibilities expand
endlessly if we can dynamically open and close the filter over time in response to our key presses. When
plucking the string of a bass, for example, the high frequency overtones excited by the string pluck die
away very quickly while the lower fundamental rings out for much longer. We can approximate this by
using the FILTER ENVELOPE to open the filter and then quickly close it, getting a short pop and buzz
from the excitement of a note that quickly decays to a low tone.
Let's set MODE to 4P LOW PASS and CUTOFF all the way down to 9 o'clock. This is so low that we've
almost filtered out the entire sound and you likely can't hear anything! But if we then move the EG
AMOUNT knob clockwise to about 3 o'clock something magical happens – the filter opens when we press
a key and then closes.
We've given a dynamic shape and articulation to our sound – the timbral characteristics of the sound now
change over time. Play with the settings of the FILTER ENVELOPE to explore how different settings affect
the shape of a note in time. ATTACK adds a gradual fade in to the sound while DECAY controls how long
it takes for those initial high frequencies to get filtered out. In essence our FILTER ENVELOPE is turning
the CUTOFF knob for us and SUSTAIN sets where that automated motion of the CUTOFF knob will hold
while we keep a key pressed down. RELEASE sets the time it takes for the filter to finally fully close down
to the setting set by CUTOFF once a key is depressed.
The AMPLITUDE ENVELOPE works the same way but instead controls the AMPLIFIER, controlling the
loudness of a sound over time. Experiment with the controls of both ENVELOPES to get a handle of their
effect on the sound. For a nice tight bass the following settings work well:
FILTER ENVELOPE: ATTACK fully ccw, DECAY noon, SUSTAIN 9 o'clock, RELEASE noon
AMPLITUDE ENVELOPE: ATTACK fully ccw, DECAY 9 o'clock, SUSTAIN fully cw, RELEASE noon
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