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Merged
mishan merged 1 commit into from
Oct 4, 2026
Merged

dsp: a bend knob on guitar and analog #335

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22 changes: 21 additions & 1 deletion dsp/analog.dsp
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,9 @@
# THE FILTER IS 24 dB AN OCTAVE: two filt::svf low-passes in series,
# the resonance on the second, the cutoff opened by its own envelope and
# by velocity, and tracking the keyboard by `Key Track'.
#
# `Bend' is the pitch wheel, in semitones and slewed over 40 ms: a piece
# rides it with a chanarg sink (`chanarg = "bend"').

name "Analog";
author "Misha Nasledov";
Expand Down Expand Up @@ -99,6 +102,13 @@ category "Leads and stabs";
@drift.label = "Drift (cents)";
@drift.group = "Warmth";

@bend = 0;
@bend.widget = 1;
@bend.min = -12;
@bend.max = 12;
@bend.label = "Bend (semitones)";
@bend.group = "Oscillators";

@cutoff = 1200;
@cutoff.widget = 1;
@cutoff.min = 40;
Expand Down Expand Up @@ -190,10 +200,20 @@ node ionode {
play = env->play;
};

node freq misc::midi2freq {
node pitch misc::midi2freq {
note = ionode->note;
};

node bend misc::slew {
in = @bend;
time = 40 ms;
};

node freq math::mul {
in0 = pitch->out;
in1 = exp2(bend->out / 12);
};

# One wanderer per oscillator, in cents, and one for the cutoff.
node driftc misc::drift { rate = 0.3; depth = @drift; seed = ionode->note; };
node driftl misc::drift { rate = 0.37; depth = @drift; seed = ionode->note + 1000; };
Expand Down
20 changes: 19 additions & 1 deletion dsp/guitar.dsp
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,13 @@
# Velocity is in the burst's level and in the damping, so a hard pick
# starts brighter and settles to where a soft one started -- a string
# does that, and an envelope on a filter only pretends to.
#
# `Bend' is in semitones and is the channel's, like a pitch wheel: a
# piece drives it with a chanarg sink (`chanarg = "bend"') from a
# gen::steps row, which is a lead guitarist's bend on a single line. It
# moves the loop's length and not its decay, and it is slewed over 40 ms
# so a step in the row is a push rather than a jump. At 0 the string is
# exactly as it was.

name "Guitar";
author "Misha Nasledov";
Expand Down Expand Up @@ -94,6 +101,12 @@ category "Plucked";
@a.max = 100ms;
@a.label = "Attack";

@bend = 0;
@bend.widget = 1;
@bend.min = -2;
@bend.max = 2;
@bend.label = "Bend (semitones)";

@r = 100 ms;
@r.widget = 1;
@r.min = 5ms;
Expand All @@ -112,6 +125,11 @@ node freq misc::midi2freq {
note = ionode->note;
};

node bend misc::slew {
in = @bend;
time = 40 ms;
};

node noise osc::noise {
color = 0;
amp = 1;
Expand Down Expand Up @@ -146,7 +164,7 @@ node pos filt::svf {
# guitar has.
node string filt::comb {
in = pos->out_band;
freq = freq->out;
freq = freq->out * exp2(bend->out / 12);
feedback = clamp(pow(10, -3 / (@decay * @mute * freq->out)), 0, 0.9995);
damp = clamp(@tone - ionode->velocity * @bright, 0, 0.9);
size = 100 ms;
Expand Down
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