Moog Music MF-107 FreqBox - Manual (Page 13)

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yet bright. Pulse waves contain all harmonics, but the amplitude of the
harmonics varies with pulse width.
A triangle wave is a symmetrical waveform (figure 12D). As it turns
out all symmetrical waveforms have only odd harmonics. With a triangle
wave the amplitude of the harmonics decrease much faster than a square
wave (exponentially), which gives it a much mellower sound, closer to a
sine wave than a square wave.
Hard Sync
The term Hard Sync is a synthesis term that traditionally refers
to resetting the start of an oscillator’s waveform at the frequency of
another oscillator, called the Master Oscillator. It is called Sync because
the oscillator that is restarted takes on the frequency of the Master
Figure 13 - Hard Sync
oscillator, seemingly
"synchronized"
in frequency (see
figure 13), yet with
a new more complex
waveform. The
effect is strongest as
long as the Master
Oscillator frequency
is lower than the oscillator that is reset. In fact, if the Master Oscillator is
much higher in frequency than the synced oscillator, the synced oscillator
signal becomes weak and possibly inaudible. This is a really important
concept when using the FreqBox!
In the FreqBox, instead of using a second Oscillator as the Master, the
signal at the input is used to reset the FreqBox’s VCO waveform. This
means the following are very important:
- The simpler the input signal, the cleaner and more predictable the
Synced oscillator will be.
- If the input signal is not lower in frequency than the FreqBox VCO,
then you may not hear anything at the output!
Hard Sync sounds are often aggressive in character, like hard
distortion, especially if the waveform of the synced oscillator is a square
wave. As you sweep the frequency of the synced oscillator, it sounds like
you are sweeping through the harmonics of the master signal. A good
example of a hard sync is the synth sound in the Car’s hit "Let’s Go".