commit 93c50df3320adabf2d573fa30de09b1dff2db3a6
parent 0e1bbf7abbe12cd0d0695af22fbb6e8292724176
Author: Matt Demanett <matt@demanett.net>
Date: Tue, 1 May 2018 01:08:26 -0400
Modify VCA for true decibels response; add VCA-L linear-response VCA.
Diffstat:
10 files changed, 390 insertions(+), 6 deletions(-)
diff --git a/benchmarks/signal_benchmark.cpp b/benchmarks/signal_benchmark.cpp
@@ -1,4 +1,6 @@
+#include <vector>
+
#include <benchmark/benchmark.h>
#include "dsp/noise.hpp"
@@ -6,6 +8,46 @@
using namespace bogaudio::dsp;
+static void BM_DecibelsToAmplitude(benchmark::State& state) {
+ std::vector<float> buf = { 10.0f, 6.0f, 3.0f, 0.0f, -3.0f, -6.0f, -10.0f, -30.0f, -60.0f };
+ int i = 0;
+ for (auto _ : state) {
+ i = ++i % buf.size();
+ benchmark::DoNotOptimize(decibelsToAmplitude(buf.at(i)));
+ }
+}
+BENCHMARK(BM_DecibelsToAmplitude);
+
+static void BM_AmplitudeToDecibels(benchmark::State& state) {
+ std::vector<float> buf = { 0.0001f, 0.0001f, 0.001f, 0.01, 0.1f, 0.3f, 0.5f, 0.8f, 1.0f, 1.5f, 2.0f, 5.0f, 10.0f };
+ int i = 0;
+ for (auto _ : state) {
+ i = ++i % buf.size();
+ benchmark::DoNotOptimize(amplitudeToDecibels(buf.at(i)));
+ }
+}
+BENCHMARK(BM_AmplitudeToDecibels);
+
+static void BM_Amplifier(benchmark::State& state) {
+ WhiteNoiseGenerator r;
+ const int n = 256;
+ float samples[n];
+ for (int i = 0; i < n; ++i) {
+ samples[i] = r.next();
+ }
+ std::vector<float> decibels = { 10.0f, 6.0f, 3.0f, 0.0f, -3.0f, -6.0f, -10.0f, -30.0f, -60.0f };
+
+ Amplifier a;
+ int i = 0, j = 0;
+ for (auto _ : state) {
+ i = ++i % decibels.size();
+ j = ++j % n;
+ a.setLevel(decibels.at(i));
+ benchmark::DoNotOptimize(a.next(samples[j]));
+ }
+}
+BENCHMARK(BM_Amplifier);
+
static void BM_SlewLimiter_Fast(benchmark::State& state) {
WhiteNoiseGenerator r;
const int n = 256;
diff --git a/res-src/VCAL-src.svg b/res-src/VCAL-src.svg
@@ -0,0 +1,150 @@
+<svg
+ version="1.1"
+ xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink"
+ width="45"
+ height="380"
+ viewBox="0 0 45 380"
+>
+ <style>
+ text {
+ fill: #333;
+ font-family: 'Roboto', sans-serif;
+ font-weight: bold;
+ }
+ text.title {
+ font-family: 'Comfortaa', sans-serif;
+ font-weight: normal;
+ }
+ text.brand {
+ font-family: 'Audiowide', sans-serif;
+ font-weight: bold;
+ }
+ </style>
+
+ <defs>
+ <symbol id="knob" viewBox="0 0 45px 45px">
+ <g transform="translate(22.5 22.5)">
+ <polyline points="-5,0 5,0" stroke-width="1" stroke="#00f" />
+ <polyline points="0,-5 0,5" stroke-width="1" stroke="#00f" />
+ <circle cx="0" cy="0" r="12.5" stroke-width="1" stroke="#00f" fill="none" />
+ </g>
+ </symbol>
+
+ <symbol id="knobguide" viewBox="0 0 45px 45px">
+ <g transform="translate(22.5 22.5)">
+ <g transform="rotate(-240) translate(15 0)">
+ <text font-size="5.0pt" transform="translate(3 0) rotate(240) translate(-2.2 2.2)">0</text>
+ </g>
+ <g transform="rotate(-210) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(-180) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(-150) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(-120) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(-90) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(-60) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(-30) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(0) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(30) translate(15 0)">
+ <polyline points="0,0 2.5,0" stroke-width="0.3" stroke="#333" />
+ </g>
+ <g transform="rotate(60) translate(15 0)">
+ <text font-size="5.0pt" transform="translate(3 0) rotate(-60) translate(-4 2.2)">10</text>
+ </g>
+ </g>
+ </symbol>
+
+ <symbol id="input" viewBox="0 0 24px 24px">
+ <g transform="translate(12 12)">
+ <circle cx="0" cy="0" r="5" stroke-width="1" stroke="#0f0" fill="#0f0" />
+ <circle cx="0" cy="0" r="10.5" stroke-width="3" stroke="#0f0" fill="none" />
+ </g>
+ </symbol>
+
+ <symbol id="output" viewBox="0 0 24px 24px">
+ <g transform="translate(12 12)">
+ <circle cx="0" cy="0" r="5" stroke-width="1" stroke="#f00" fill="#f00" />
+ <circle cx="0" cy="0" r="10.5" stroke-width="3" stroke="#f00" fill="none" />
+ </g>
+ </symbol>
+ </defs>
+
+ <rect width="100%" height="100%" fill="#ddd" />
+ <polyline points="1,1 44,1 44,379 1,379 1,1" stroke="#e4e4e4" stroke-width="0.5" fill="none" />
+ <polyline points="0.5,0.5 44.5,0.5 44.5,379.5 0.5,379.5 0.5,0.5" stroke="#ebebeb" stroke-width="0.8" fill="none" />
+ <polyline points="0,0 45,0 45,380 0,380 0,0" stroke="#f2f2f2" stroke-width="1" fill="none" />
+
+ <!-- <polyline points="22.5,0 22.5,380" stroke-width="0.5" stroke="#0f0" /> -->
+ <!-- <rect width="45" height="10" fill="#0f0" transform="translate(0 68)" /> -->
+ <!-- <rect width="45" height="10" fill="#0f0" transform="translate(0 127)" /> -->
+ <!-- <rect width="45" height="10" fill="#0f0" transform="translate(0 177)" /> -->
+
+ <g transform="rotate(-90) translate(-376 13)">
+ <text class="title" font-size="7pt" letter-spacing="1px">VCA-L</text>
+ <g transform="translate(0 12)">
+ <text class="brand" font-size="7pt" letter-spacing="2px">BGA</text>
+ <rect width="3.0" height="3" fill="#ddd" transform="translate(11.5 -5)" />
+ </g>
+ </g>
+
+ <g transform="translate(0 25)">
+ <text font-size="6pt" letter-spacing="2px" transform="translate(5.5 0)">1</text>
+ <use id="LEVEL1_PARAM" xlink:href="#knob" transform="translate(0 -6)" />
+ <use xlink:href="#knobguide" transform="translate(0 -6)" />
+ </g>
+
+ <g transform="translate(0 63)">
+ <g transform="translate(5.5 0)">
+ <rect width="34" height="10" fill="#fafafa" transform="translate(0 63)" />
+ <rect width="34" height="70" rx="5" fill="#fafafa" />
+ <use id="CV1_INPUT" xlink:href="#input" transform="translate(5 3)" />
+ <text font-size="5pt" letter-spacing="2px" transform="translate(12.5 35)">CV</text>
+ <use id="IN1_INPUT" xlink:href="#input" transform="translate(5 38)" />
+ <text font-size="5pt" letter-spacing="2px" transform="translate(12.5 70)">IN</text>
+ </g>
+ <g transform="translate(5.5 76)">
+ <rect width="34" height="10" fill="#bbb" transform="translate(0 -3)" />
+ <rect width="34" height="35" rx="5" fill="#bbb" />
+ <use id="OUT1_OUTPUT" xlink:href="#output" transform="translate(5 0)" />
+ <text font-size="5pt" letter-spacing="2px" transform="translate(8.3 32)">OUT</text>
+ </g>
+ </g>
+
+ <g transform="translate(0 186)">
+ <text font-size="6pt" letter-spacing="2px" transform="translate(5.5 0)">2</text>
+ <use id="LEVEL2_PARAM" xlink:href="#knob" transform="translate(0 -6)" />
+ <use xlink:href="#knobguide" transform="translate(0 -6)" />
+ </g>
+
+ <g transform="translate(0 224)">
+ <g transform="translate(5.5 0)">
+ <rect width="34" height="10" fill="#fafafa" transform="translate(0 63)" />
+ <rect width="34" height="70" rx="5" fill="#fafafa" />
+ <use id="CV2_INPUT" xlink:href="#input" transform="translate(5 3)" />
+ <text font-size="5pt" letter-spacing="2px" transform="translate(12.5 35)">CV</text>
+ <use id="IN2_INPUT" xlink:href="#input" transform="translate(5 38)" />
+ <text font-size="5pt" letter-spacing="2px" transform="translate(12.5 70)">IN</text>
+ </g>
+ <g transform="translate(5.5 76)">
+ <rect width="34" height="10" fill="#bbb" transform="translate(0 -3)" />
+ <rect width="34" height="35" rx="5" fill="#bbb" />
+ <use id="OUT2_OUTPUT" xlink:href="#output" transform="translate(5 0)" />
+ <text font-size="5pt" letter-spacing="2px" transform="translate(8.3 32)">OUT</text>
+ </g>
+ </g>
+</svg>
diff --git a/res/VCAL.svg b/res/VCAL.svg
Binary files differ.
diff --git a/src/VCA.cpp b/src/VCA.cpp
@@ -2,18 +2,20 @@
#include "VCA.hpp"
void VCA::step() {
- channelStep(inputs[IN1_INPUT], outputs[OUT1_OUTPUT], params[LEVEL1_PARAM], inputs[CV1_INPUT]);
- channelStep(inputs[IN2_INPUT], outputs[OUT2_OUTPUT], params[LEVEL2_PARAM], inputs[CV2_INPUT]);
+ channelStep(inputs[IN1_INPUT], outputs[OUT1_OUTPUT], params[LEVEL1_PARAM], inputs[CV1_INPUT], _amplifier1);
+ channelStep(inputs[IN2_INPUT], outputs[OUT2_OUTPUT], params[LEVEL2_PARAM], inputs[CV2_INPUT], _amplifier2);
}
-void VCA::channelStep(Input& input, Output& output, Param& knob, Input& cv) {
+void VCA::channelStep(Input& input, Output& output, Param& knob, Input& cv, Amplifier& amplifier) {
if (input.active && output.active) {
float level = knob.value;
if (cv.active) {
level *= clamp(cv.value, 0.0f, 10.0f) / 10.0f;
}
- level = powf(level, 2.0);
- output.value = level * input.value;
+ level = 1.0f - level;
+ level *= Amplifier::minDecibels;
+ amplifier.setLevel(level);
+ output.value = amplifier.next(input.value);
}
else {
output.value = 0.0;
diff --git a/src/VCA.hpp b/src/VCA.hpp
@@ -1,6 +1,9 @@
#pragma once
#include "bogaudio.hpp"
+#include "dsp/signal.hpp"
+
+using namespace bogaudio::dsp;
extern Model* modelVCA;
@@ -31,10 +34,13 @@ struct VCA : Module {
NUM_LIGHTS
};
+ Amplifier _amplifier1;
+ Amplifier _amplifier2;
+
VCA() : Module(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS) {}
virtual void step() override;
- void channelStep(Input& input, Output& output, Param& knob, Input& cv);
+ void channelStep(Input& input, Output& output, Param& knob, Input& cv, Amplifier& amplifier);
};
} // namespace bogaudio
diff --git a/src/VCAL.cpp b/src/VCAL.cpp
@@ -0,0 +1,62 @@
+
+#include "VCAL.hpp"
+
+void VCAL::step() {
+ channelStep(inputs[IN1_INPUT], outputs[OUT1_OUTPUT], params[LEVEL1_PARAM], inputs[CV1_INPUT]);
+ channelStep(inputs[IN2_INPUT], outputs[OUT2_OUTPUT], params[LEVEL2_PARAM], inputs[CV2_INPUT]);
+}
+
+void VCAL::channelStep(Input& input, Output& output, Param& knob, Input& cv) {
+ if (input.active && output.active) {
+ float level = knob.value;
+ if (cv.active) {
+ level *= clamp(cv.value, 0.0f, 10.0f) / 10.0f;
+ }
+ output.value = level * input.value;
+ }
+ else {
+ output.value = 0.0;
+ }
+}
+
+struct VCALWidget : ModuleWidget {
+ VCALWidget(VCAL* module) : ModuleWidget(module) {
+ box.size = Vec(RACK_GRID_WIDTH * 3, RACK_GRID_HEIGHT);
+
+ {
+ SVGPanel *panel = new SVGPanel();
+ panel->box.size = box.size;
+ panel->setBackground(SVG::load(assetPlugin(plugin, "res/VCAL.svg")));
+ addChild(panel);
+ }
+
+ addChild(Widget::create<ScrewSilver>(Vec(0, 0)));
+ addChild(Widget::create<ScrewSilver>(Vec(box.size.x - 15, 365)));
+
+ // generated by svg_widgets.rb
+ auto level1ParamPosition = Vec(9.5, 28.5);
+ auto level2ParamPosition = Vec(9.5, 189.5);
+
+ auto cv1InputPosition = Vec(10.5, 66.0);
+ auto in1InputPosition = Vec(10.5, 101.0);
+ auto cv2InputPosition = Vec(10.5, 227.0);
+ auto in2InputPosition = Vec(10.5, 262.0);
+
+ auto out1OutputPosition = Vec(10.5, 139.0);
+ auto out2OutputPosition = Vec(10.5, 300.0);
+ // end generated by svg_widgets.rb
+
+ addParam(ParamWidget::create<Knob26>(level1ParamPosition, module, VCAL::LEVEL1_PARAM, 0.0, 1.0, 0.5));
+ addParam(ParamWidget::create<Knob26>(level2ParamPosition, module, VCAL::LEVEL2_PARAM, 0.0, 1.0, 0.5));
+
+ addInput(Port::create<Port24>(cv1InputPosition, Port::INPUT, module, VCAL::CV1_INPUT));
+ addInput(Port::create<Port24>(in1InputPosition, Port::INPUT, module, VCAL::IN1_INPUT));
+ addInput(Port::create<Port24>(cv2InputPosition, Port::INPUT, module, VCAL::CV2_INPUT));
+ addInput(Port::create<Port24>(in2InputPosition, Port::INPUT, module, VCAL::IN2_INPUT));
+
+ addOutput(Port::create<Port24>(out1OutputPosition, Port::OUTPUT, module, VCAL::OUT1_OUTPUT));
+ addOutput(Port::create<Port24>(out2OutputPosition, Port::OUTPUT, module, VCAL::OUT2_OUTPUT));
+ }
+};
+
+Model* modelVCAL = Model::create<VCAL, VCALWidget>("Bogaudio", "Bogaudio-VCAL", "VCA-L", AMPLIFIER_TAG, ATTENUATOR_TAG, DUAL_TAG, UTILITY_TAG);
diff --git a/src/VCAL.hpp b/src/VCAL.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include "bogaudio.hpp"
+
+extern Model* modelVCAL;
+
+namespace bogaudio {
+
+struct VCAL : Module {
+ enum ParamsIds {
+ LEVEL1_PARAM,
+ LEVEL2_PARAM,
+ NUM_PARAMS
+ };
+
+ enum InputsIds {
+ CV1_INPUT,
+ IN1_INPUT,
+ CV2_INPUT,
+ IN2_INPUT,
+ NUM_INPUTS
+ };
+
+ enum OutputsIds {
+ OUT1_OUTPUT,
+ OUT2_OUTPUT,
+ NUM_OUTPUTS
+ };
+
+ enum LightsIds {
+ NUM_LIGHTS
+ };
+
+ VCAL() : Module(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS) {}
+
+ virtual void step() override;
+ void channelStep(Input& input, Output& output, Param& knob, Input& cv);
+};
+
+} // namespace bogaudio
diff --git a/src/bogaudio.cpp b/src/bogaudio.cpp
@@ -31,6 +31,7 @@
#include "Sums.hpp"
#include "Switch.hpp"
#include "VCA.hpp"
+#include "VCAL.hpp"
#include "Test.hpp"
#include "Test2.hpp"
@@ -85,6 +86,9 @@ void init(rack::Plugin *p) {
#endif
p->addModel(modelSwitch);
p->addModel(modelVCA);
+#ifdef EXPERIMENTAL
+ p->addModel(modelVCAL);
+#endif
#ifdef TEST
p->addModel(modelTest);
diff --git a/src/dsp/signal.cpp b/src/dsp/signal.cpp
@@ -1,10 +1,53 @@
#include <assert.h>
+#include <algorithm>
#include "signal.hpp"
using namespace bogaudio::dsp;
+const float Amplifier::minDecibels = -60.0f;
+const float Amplifier::maxDecibels = 20.0f;
+const float Amplifier::decibelsRange = maxDecibels - minDecibels;
+
+void Amplifier::LevelTable::_generate() {
+ const float rdb = 6.0f;
+ const float tdb = Amplifier::minDecibels + rdb;
+ const float ta = decibelsToAmplitude(tdb);
+ _table[0] = 0.0f;
+ for (int i = 1; i < _length; ++i) {
+ float db = Amplifier::minDecibels + (i / (float)_length) * Amplifier::decibelsRange;
+ if (db <= tdb) {
+ _table[i] = ((db - minDecibels) / rdb) * ta;
+ }
+ else {
+ _table[i] = decibelsToAmplitude(db);
+ }
+ }
+}
+
+void Amplifier::setLevel(float db) {
+ if (_db != db) {
+ _db = db;
+ if (_db > minDecibels) {
+ if (_db < maxDecibels) {
+ _level = _table.value(((_db - minDecibels) / decibelsRange) * _table.length());
+ }
+ else {
+ _level = decibelsToAmplitude(_db);
+ }
+ }
+ else {
+ _level = 0.0f;
+ }
+ }
+}
+
+float Amplifier::next(float s) {
+ return _level * s;
+}
+
+
bool PositiveZeroCrossing::next(float sample) {
switch (_state) {
case NEGATIVE_STATE: {
diff --git a/src/dsp/signal.hpp b/src/dsp/signal.hpp
@@ -1,8 +1,43 @@
#pragma once
+#include <math.h>
+
+#include "table.hpp"
+
namespace bogaudio {
namespace dsp {
+// "amplitude" is 0-whatever here, with 1 (=0db) meaning unity gain.
+inline float decibelsToAmplitude(float db) {
+ return powf(10.0f, db * 0.05f);
+}
+
+inline float amplitudeToDecibels(float amplitude) {
+ return 20.0f * log10f(amplitude);
+}
+
+struct Amplifier {
+ static const float minDecibels;
+ static const float maxDecibels;
+ static const float decibelsRange;
+ struct LevelTable : Table {
+ LevelTable(int n) : Table(n) {}
+ virtual void _generate() override;
+ };
+ struct StaticLevelTable : StaticTable<LevelTable, 11> {};
+
+ float _db = 0.0f;
+ float _level;
+ const Table& _table;
+
+ Amplifier() : _table(StaticLevelTable::table()) {
+ setLevel(minDecibels);
+ }
+
+ void setLevel(float db);
+ float next(float s);
+};
+
struct PositiveZeroCrossing {
const float positiveThreshold = 0.01f;
const float negativeThreshold = -positiveThreshold;
