User Manual

STOMP SECTION 25
Ring Modulator Here, the signal is modulated by a sine oscillator. The pitch of the oscillator is
controlled with the ‘Manual’ parameter - note that the ‘Manual’ parameter is
bipolar, therefore a setting of ‘0’ will have no eect. Lower settings produce
a tremolo-like eect, whereas higher settings bend the complete harmonic
structure of the instrument into a bell-like character by shifting every frequency
component either upwards (sum frequency) or downwards (dierence
frequency).
The ‘Stereo’ parameter divides the sum and dierence frequencies into the left
and right channel. The bipolar nature of the ‘Manual’ parameter can now be
used to reverse the stereo panorama.
As usual, the ‘Mix’ parameter adds the direct signal. With ‘Mix’ in the middle
position, the ring modulation becomes amplitude modulation.
Frequency Shifter The frequency shifter is a rarely seen eect and can be thought of as a ‘deluxe’
ring modulator. Even today, only a handful of frequency shifters exist in the
digital domain.
It is as useful in creating beautiful, subtle harmonic deviations as it is in
producing high-pitched, clangourous noise. Like the ring modulator, it uses
a sine wave to modulate the signal, but in such a way as to produce only the
‘sum’ or ‘dierence’ frequencies of the two signals. In contrast to a pitch shifter,
which preserves the dependencies of the harmonics, the frequency shifter
bends these dependencies, resulting in a bell-like spectrum. It’s not unlike a
shortwave radio that hasn’t been tuned correctly.
Use the ‘Manual’ parameter to determine the pitch of the sine wave. This is
a bipolar parameter where the centre position (0) will result in no audible
frequency shifting.
Turning ‘Manual’ clockwise results in a linear frequency shift upwards, while
turning it counter-clockwise results in a downwards shift. Note how the shifted
signal loses its harmonic structure.
When ‘Manual’ is adjusted to the far left, you will notice that the pitch starts to
rise again. This is the result of frequencies being shifted past 0Hz, which causes
them to be mirrored upwards.
The ‘Stereo’ parameter allows continuous adjustment of the phase of the left
and right channels, thereby creating a subtle, or blatant, stereo-widening eect.
 At the lowest pitch, or longest delay, it will resonate on an E major chord.