Operation Manual

40 Parameters
after the EQ module. In this configuration, the control signal of the Compressor is then the output
signal from the EQ module while the input signal to the compressor is determined by the position
of the SC button. When it is on, the Compressor is in a side-chain configuration. The input signal
of the Compressor is then the output signal from the synthesizer. When it is off, the input signal
of the Compressor is the output signal from the EQ module.
Using the compressor in side chain configuration is useful when one wants to trigger the com-
pressor using other criteria than the general level of the signal to be compressed. For example, a
sound with a lot of bass would easily trigger the Compressor when playing low notes. In order
to avoid that, the EQ module would be set to filter out low frequency components. This signal
would then be used to control the Compressor while the input signal to the Compressor would
still include these low frequency components.
The attenuation or gain reduction level meter, located in the middle of the module, indicates
the amount of compression applied by the module. It is the difference between the input and output
signals of the module before makeup gain is applied.
4.3.3 Delay
The Delay module consists in a stereo feedback loop with a variable delay in the feedback. It is
used to produce an echo effect when the delay time is long (greater than 100 ms) or to color the
sound when the delay time is short (smaller than 100 ms).
The Delay knob is used to adjust the amount of delay, in seconds, introduced by the effect.
Turning this knob clockwise increases the delay. The Feedback parameter is a gain factor, varying
in the range between 0 and 1, applied to the signal at the end of the delay lines. It controls the
amount of signal that is re-injected in the feedback loop. In its leftmost position, the value of this
parameter is 0 and no signal is re-introduced in the delay line which means that the signal is only
delayed once. Turning the knob clockwise increases the amount of signal re-injected at the end of
the feedback loop and therefore allows one to control the duration of the echo for a given delay
time. In its rightmost position, the gain coefficient is equal to 1 which means that all the signal is
re-injected into the feedback loop and that the echo will not stop. In addition to this gain factor,
low pass filtering can also be applied to the signal re-injected into the feedback loop. The cutoff
frequency of this filter is controlled using the Cutoff knob.
The Pan knob is used to balance the input signal between the left and right channels. In its
leftmost position, signal is only fed into the left delay line and one hears clearly defined echo
first from the left channel and then from the right channel and so on. In its rightmost position,
the behavior is similar but with the first echo coming from the right channel. These two extreme
position correspond to the standard ping pong effect but a a less extreme behavior can be obtained