Converting bipolar to unipolar signal
is a common mistake that we always made in Reaktor. When we want to connect
bipolar signal to unipolar signal we need to convert them otherwise it will not
sound good because of polarity flapping. For example, when we are building a
tremolo effect, we use LFO to modulate the Amplitude of the wave shape by
multiply with the Envelope Generator signal so we can use the Envelope
Generator to shape the Amplitude of the wave shape as well. But the problem
here is that the LFO signal is bipolar -1 to +1 and the Envelope Generator is
an unipolar 0 - 1. Therefore, multiply these two signals will not give us a
perfect tremolo effect. So to solve this problem we need to convert the bipolar
to unipolar signal. All we have to do here is to take the output from LFO that
is -1 to +1 then rescale it in half and multiply by 0.5. Now it goes to -0.5 to
+0.5 then add on 0.5, so the -0.5 and +0.5 become 0 and the 0.5+0.5 become 1.
So we basically take bipolar -1 to +1 signal going into unipolar 0-1 signals.
This it the problem that we encountered when we built our tremolo effect and it
took us a while to understand it and solved the problem. Also as you can hear
the samples that we recorded below. It used sine wave and the frequency rate
was set to 1Hz. The one without converting bipolar to unipolar never gave us a
perfect 1 Hz oscillation. Other one with converting bipolar to unipolar gave us
a perfect tremolo effect. Obviously, if you compare two of them, you will
definitely hear the different between them.
Without Converting bipolar to unipolar
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