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Programming Examples
Example 3
Example 3
Sample and Hold; Using a FUN
This example will use one of the FUNs to create a sample and hold program. As usual, start
with Program 199, and press EDIT. While you're on the ALG page, select a value of
"PARAMETRIC EQ" for the center DSP function block. Then select the KEYMAP page, and
select the keymap 152 Dull Sawtooth.
Now press the more> soft button, then the F1 FRQ soft button. This enables you to set the
frequency for the parametric EQ, which will set the depth of the modulation for the sample and
hold function. The Coarse parameter will already be selected; set its value to D#4 311 Hz.
Cursor down to the KeyTrk parameter, and set its value to 100 cents per key. Cursor over to the
Src1 parameter, and set its value to FUN1 (1, 1, 2, ENTER). Cursor down once to the Depth
parameter, and set its value to a fairly large negative number, like -4000 cents.
Next, press the F3 AMP soft button, to set the amplitude for the Parametric EQ (make sure you
don't select F4 FINAL AMP). Set the value of the Adjust parameter to about 17 dB.
Now press either <more> soft button until you see the LFO soft button. Press the LFO button to
select the LFO page. We'll program LFO1 as a square wave, then use it as one of the FUN's
inputs.
Select the MnRate parameter for LFO1 and set it to a value of 5.00 Hz. Select the MxRate
parameter and set its value to 15.00 Hz. Select the RateCt parameter and set it to a value of
Data. Select the Shape parameter and set its value to Square. That's it for the LFO page.
Next press the FUN soft button to select the FUN page. Select the Input A parameter for FUN1,
and set its value to LFO1 (1, 1, 4, ENTER). Select the Input B parameter and set its value to
RandV1 (1, 0, 8, ENTER). Finally, select the Function parameter, and set its value to "Sample B
On A." Now when you play and hold a note, you'll hear the sample and hold effect. Use your
MIDI controller's data slider (or a programmable control set to MIDI 06) to control the rate of
the effect.
Here's what's happening. The square wave of the LFO cycles from +1 to -1. Every time this
occurs, the random signal generator (RandV1) randomly picks a value which changes the
frequency of the parametric EQ. There are lots of ways to set up sample and hold effects, but
the FUN is the basic element. In this case, every time the value of the FUN's "A" input (LFO1)
becomes greater than +.5, the value of the "B" input (RandV1) is sampled. That value becomes
the FUN's output until the next time the value of the "A" input becomes greater than +.5 (see
Chapter 16 for more). In this example, the FUN's output modulates the frequency of the EQ,
and causes rapid changes in timbre.
Now we'll apply the FUN to control the pitch of the sound as well. Press either of the <more>
soft buttons until the PITCH soft button is visible, and press it to select the PITCH page. Select
the Src1 parameter and set its value to FUN1. Select the Depth parameter and set its value to
about 400 cents. Now the sound's pitch will fluctuate in sync with the EQ effect.
19-6
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