FXAlg #967: Mono -> Stereo
Algorithm Reference-172
FXAlg #967: Mono -> Stereo
Stereo simulation from a mono input signal
Allocation Units:
1
Mono -> Stereo is an algorithm which creates a stereo signal from a mono input signal. The algorithm works by
combining a number of band-splitting, panning and delay tricks. The In Select parameter lets you choose the left or
right channel for the mono input, or you may choose to sum the left and right inputs.
Block diagram of Mono -> Stereo effect.
The mono input signal is split into three frequency bands (Low, Mid, and High). The frequencies at which the bands
get split are set with the Crossover parameters. Each band can then be delayed and panned to some position within
the stereo field.
The final step manipulates the sum and difference signals of the pseudo-stereo signal created by recombining the
split frequency bands. The sum of left and right channels represents the mono or center mix of your stereo signal.
The difference of left and right channels contains the part of the signal that contains stereo spatial information. The
Stereo Image algorithm has controls to change the relative amounts of sum (or center) versus difference signals. By
increasing the difference signal, you can broaden the stereo image. Be warned, though, that too much difference
signal will make your stereo image sound ÒphaseyÓ. With phasey stereo, acoustic images become difficult to
localize and can sound like they are coming from all around you or from within your head.
A bass shelf filter on the difference signal is also provided. By boosting only the low frequencies of the difference
signal, you can greatly improve your sense of stereo envelopment without destroying your stereo sound field.
Envelopment is the feeling of being surrounded by your acoustic environment. Localized stereo images still come
from between your stereo loudspeakers, but there is an increased sense of being wrapped in the sound field.
Parameters:
PAGE 1
In/Out
In or Out
Out Gain
Off, -79.0 to 24.0 dB
CenterGain
Off, -79.0 to 24.0 dB
Diff Gain
Off, -79.0 to 24.0 dB
In Select
L, R, or (L+R)/2
DiffBassG
-79.0 to 24.0 dB
DiffBassF
16 to 25088 Hz
Delay
Delay
Delay
Pan
Pan
Pan
L Input
R Input
L Output
R Output
-
-
Center Gain
Diff Gain
1/2
