Alesis Plus User Manual page 20

A
Amp
INPUT SIGNAL
B
Amp
UP OUTPUT
C
PITCH SHIFT
AMOUNT = 200Hz
Amp
DOWN OUTPUT
In Figure 1A, the fundamental (or frequency that we perceive as the instrument's
pitch) is 500 Hz. The harmonics are normally even multiples of the fundamental,
or 2 times the fundamental, 3 times the fundamental, 4 times the fundamental,
etc. In this case, the 2nd harmonic is 1KHz (1000 cycles per second), or twice
the fundamental of 500Hz, and the 4th harmonic is 2KHz, or 4 times the
fundamental.
In Figure 1B, the Pitch Shift amount has been set to 200Hz, which means that
the fundamental and all of its related harmonics are shifted up by the same
200Hz amount. This means that the fundamental has been shifted to 700Hz, the
2nd harmonic is now at 1.2KHz (normally it should be 2 times the fundamental,
or 1.4KHz), and the 4th harmonic is 2.2KHz (normally it should be 2.8KHz).
In Figure 1C, the Pitch Shift amount is shifted down by 200Hz, which means that
the fundamental and all of its related harmonics are shifted down by the same
200Hz amount. This means that the fundamental has been shifted to 300Hz, the
2nd harmonic is now at 800Hz (normally it should be 2 times the fundamental, or
600Hz), and the 4th harmonic is 1.8KHz (normally it should be 1.2KHz).
Since the ratio between the input signal's harmonics is not preserved, the
resulting sound is drastically different from the original.
modulators only provide a fixed mix of the Up and Down spectrums, the
20
20
Freq.
Freq.
Freq.
While usual ring