2.3.1.
Decay Jack
In addition to the Decay knob, the envelope generators have a control-voltage input jack.
Positive voltages increase the time it takes the envelope to fade out; negative voltages
decrease the time. One example of a use for these input jacks is to simulate a high-hat, using a
control voltage to vary the sound’s decay time between short and long.
2.4.
Output Controls
The last knobs on BoomTschak’s panel don’t hold many surprises. The MIX knob varies the
relative amounts of the signals from the oscillator and the filtered noise source. At its center
position, the signals are mixed in equal amounts (although their actual audible levels depend on
other things, such as the filter’s mode and frequency). Turn the knob to the left and you’ll hear
more of the oscillator, turn it to the right and you’ll hear more of the filtered noise.
The MIX jack lets you vary the balance of the signals with an external control voltage. Positive
voltages increase the level of the oscillator and decrease the level of the noise, negative
voltages do the opposite. Since the two sections of BoomTschak are flexible enough to create
complete sounds by themselves, controlling the mix with an external voltage—such as from our
Sequencer 1 Eurorack sequencer—is a viable way to produce two or more distinct drum parts
from one module.
The LEVEL knob does what you expect: it sets the overall loudness or volume of BoomTschak’s
output.
2.5.
Trigger, Choke, and Velocity Jacks
The TRIGGER jack makes BoomTschak make sound. The most appropriate signal for this input
is a pulse that rises from 0v to +5V or higher, and lasts around 5msec or longer. BoomTschak
will trigger on pulses with a lower peak level, but you’ll hear differences in its sound which may
or may not be useful.
The CHOKE jack expects the same sort of signal as the TRIGGER jack. An incoming pulse will
cause all three of BoomTschak’s envelope generators to cease their decay and immediately
drop to zero, silencing the sound. The obvious use of this jack is to simulate a cymbal choke, in
which the player strikes a cymbal and then grabs its rim to silence it. The less obvious use is to
apply periodic or random signals to this input to produce glitchy effects.
The VELOCITY jack borrows its name from MIDI parlance, allowing you to control
BoomTschak’s overall loudness with an external voltage. The input voltage is sampled when a
trigger pulse is received. Positive voltages increase the output level and negative voltages
decrease it.
