Alesis ModFX Bitrman Reference Manual page 31

What is Ring Modulation?
Ring Modulation was first used in modular synthesizers. Ring
modulation happens when two signals are multiplied by each
other, creating sum and difference frequencies that aren't in the
original source. The resulting sound is sort of like an electronic
tubular bell, noise, or metal bars being hit, depending on the
difference between the two frequencies.
When the Bitrman's in RING MOD mode, an internal digital sine
wave oscillator is used to amplitude-modulate the incoming input
signal. The [BITRNESS] knob controls this modulating
frequency, from off at full counter-clockwise to several thousand
Hertz at full clockwise. Low settings of [BITRNESS] in RING
MOD mode result in a tremolo effect, made into an autopan effect
in stereo because the modulator's phase is shifted 90° between
channels. As you raise the control while playing a single tone,
you'll hear the original tone, plus another one going up, and
another one going down. As the ring mod frequency increases, it
will sound distorted in a "signals from outer space" kind of way.
At a full clockwise setting, the Ring Mod source is very high,
resulting in a spaced-out metallic whistling sound, since the sum
and difference signals are so far from the original signal.
Inbetween those two extremes, RING MOD produces a unique
synthesized distortion effect worth exploring.
If you have your Bitrman connected in stereo, you'll notice that
RING MOD produces some interesting stereo effects.
What is Frequency Shifting?
Frequency Shifting is a relative of Ring Modulation. But instead of
giving you the sum and difference frequencies in the output, it
gives only the sum (higher frequencies), and eliminates the original
pitch entirely.
In FREQ SHIFT mode, the [BITRNESS] knob multiplies the
incoming audio by a higher and higher frequency as you turn the
knob clockwise.
Using the Bitrman
The s ettin g o f th e
[ BI TRNES S] k n ob in Rin g
Mod m od e s ets the
m od ulating fr eq ue nc y . I f it' s
o nly 2 H z, th e re su lt will be a
s ligh t tre mo lo/a utop an so un d .
I f it's 10 0 H z, a nd yo u p la y a
4 00 H z n ote, Ring Mo d will
a dd two n on ha rm o nic
s id eb an d s at 30 0 Hz + 50 0
H z to th e ou tpu t.
Fre qu en c y Sh iftin g is NO T
p itch s h iftin g (y ou ca n' t u se
this to ad d a n in te r va l o f a
fifth o r o cta ve a bo v e th e
inp ut). The pitc h o utpu t in
FREQ SH I FT m o de is n ot
h ar mo nic .
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