Random Drifting Pan

This program provides examples of use of the Panner and FUNs.  Each note is assigned a random position in the stereo spectrum, then pans between these left- and right-side positions.

Start with Default Program #199.  Select algorithm #13 so the Panner is available; since we wonÕt be using any other DSP functions for this example, set the F1 and F2 blocks to NONE.  Change the KEYMAP to something like 154 Square Wave so itÕll sustain as long as keys are held, which makes it easier to hear the effect.

On the F3 POS page, assign FUN2 to SRC1, and set DEPTH to 100%.

On the FUN edit page, setup the following:
        
                        A               B               function
        FUN1            Key St  RandV1  Sample B on A
        FUN2            FUN1            LFO1            a * b

Setup LFO1 to 1.00 HZ, triangle, phase 90 degrees.

Hold a note and hear how it drifts back and forth in the stereo spectrum: each note is assigned a different left-right distance from center.  All notes pan independently left and right, although the actual speed of the panning motion is the same for all.  The pan speeds can be varied by modulating the LFO1 rate.

WhatÕs happening: FUN1 ÒlatchesÓ a random number from RandV1 when the note is pressed.  If we didnÕt use FUN1, RandV1 would continuously Òjitter;Ó we want a to pick a value and keep it stable.

LFO1 is a bipolar triangle that cycles between +1 and -1; choosing a phase of 90 degrees causes it to always start at +1 and begin a downward slope towards -1.

FUN2, in multiplying LFO1 by the random number from FUN1, effectively becomes a limiter, controlled by the random number.  The output of FUN2 is a triangle like LFO1, but it doesnÕt necessarily go all the way between +1 and -1; it only gets as large as the random number.  Because the random number is bipolar, the output of FUN2 begins either as a negative number heading positive, or as a positive number going toward the negative.  A negative start begins the sweep from the left; a positive start begins sweeping from the right.
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Rick Auricchio             rick@taligent.com            408-974-4227
Taligent Inc.  10725 N. DeAnza Blvd.  M/S SE/1   Cupertino, CA 95014-2000 USA