Add filter

Soft/Drum/Drum.ino

 #include <hardware/pwm.h>
 #include "Envelopes.h"
+#include "Dsp.h"
 #include "Hardware.h"
 #include "Kick.h"
 #include "Snare.h"
@@ -106,6 +107,7 @@ void loop() {
   
   // Update Modulation
   if (mode_switch.mode == 0) {
+    // Modulation updates for Kick
     kick.setFrequency(freq_pot/1023.0);
     // Bigger decay values make the envelope shorter
     kick.setVolumeDecay(0.000005 + (float)chord_pot/1023.0/3000.0);
@@ -114,12 +116,16 @@ void loop() {
     kick.setPitchAmount(2.0 + (1023.0-(float)inv_pot)/1023.0*8.5);
     kick.update();
   } else if (mode_switch.mode == 1) {
+    // Modulation updates for Snare
     snare.setFrequency(freq_pot/1023.0);
     // Bigger decay values make the envelope shorter
-    snare.setVolumeDecay(0.000005 + (float)chord_pot/1023.0/3000.0);
-    snare.setPitchDecay(0.00001 + (float)inv_pot/1023.0/800.0);
+    snare.setVolumeDecay(0.00005 + (float)chord_pot/1023.0/100.0);
+    snare.setPitchDecay(0.00001 + (float)inv_pot/1023.0/200.0);
     // Increase the amount of the pitch envelope if the pitch decay is longer
     snare.setPitchAmount(2.0 + (1023.0-(float)inv_pot)/1023.0*8.5);
+    float freq = 0.0+(1023.0-(float)inv_pot)*5.0;
+    Serial.println(freq);
+    snare.setLpfFrequency(freq);
     snare.update();
   }
   

Soft/Drum/Dsp.h

+
+class LPF {
+  public:
+    float frequency = 100.00;
+    float resonance = 0.9;
+
+    float render(float sample);
+    void setFrequency(float frequency);
+    void addFrequency(float frequency);
+    void setResonance(float resonance);
+    void reset();
+
+  private:
+    float feedback;
+    float buf0 = 0.0;
+    float buf1 = 0.0;
+};
+
+
+float LPF::render(float sample) {
+  this->buf0 = this->buf0 + this->frequency * (sample - this->buf0 + this->feedback * (this->buf0 - this->buf1));
+  this->buf1 = this->buf1 + this->frequency * (this->buf0 - this->buf1);
+  return this->buf1;
+}
+
+void LPF::setFrequency(float frequency) {
+  this->frequency = 2.0 * sin(PI * frequency / 32000.0);
+  this->feedback = this->resonance + this->resonance / (1.0 - this->frequency);
+}
+
+void LPF::addFrequency(float frequency) {
+  this->frequency += 2.0 * sin(PI * frequency / 32000.0);
+  this->feedback = this->resonance + this->resonance / (1.0 - this->frequency);
+}
+
+void LPF::setResonance(float resonance) {
+  this->resonance = resonance;
+  this->feedback = this->resonance + this->resonance / (1.0 - this->frequency);
+}
+
+void LPF::reset() {
+  this->buf0 = 0.0;
+  this->buf1 = 0.0;
+}
+
+
+
+class HPF {
+  public:
+    float frequency = 100.00;
+    float resonance = 0.9;
+
+    float render(float sample);
+    void setFrequency(float frequency);
+    void addFrequency(float frequency);
+    void setResonance(float resonance);
+    void reset();
+
+  private:
+    float feedback;
+    float buf0 = 0.0;
+    float buf1 = 0.0;
+};
+
+
+float HPF::render(float sample) {
+  this->buf0 = this->buf0 + this->frequency * (sample - this->buf0 + this->feedback * (this->buf0 - this->buf1));
+  this->buf1 = this->buf1 + this->frequency * (this->buf0 - this->buf1);
+  return sample - this->buf1;
+}
+
+void HPF::setFrequency(float frequency) {
+  this->frequency = 2.0 * sin(PI * frequency / 32000.0);
+  this->feedback = this->resonance + this->resonance / (1.0 - this->frequency);
+}
+
+void HPF::addFrequency(float frequency) {
+  this->frequency += 2.0 * sin(PI * frequency / 32000.0);
+  this->feedback = this->resonance + this->resonance / (1.0 - this->frequency);
+}
+
+void HPF::setResonance(float resonance) {
+  this->resonance = resonance;
+  this->feedback = this->resonance + this->resonance / (1.0 - this->frequency);
+}
+
+void HPF::reset() {
+  this->buf0 = 0.0;
+  this->buf1 = 0.0;
+}
\ No newline at end of file

Soft/Drum/Envelopes.h

@@ -39,10 +39,12 @@ class EnvelopeSimpleLog {
     float value;
     float speed = 0.001;
     float amount = 1.0;
+    float snap = 0.005;
     void update();
     void reset();
     void setAmount(float speed);
     void setSpeed(float speed);
+    void setSnap(float snap);
 };
 
 void EnvelopeSimpleLog::update() {
@@ -50,7 +52,7 @@ void EnvelopeSimpleLog::update() {
   if (this->counter <= 0.0) {
     this->counter = 0.0;
   }
-  this->value = max(0.0, (log10(0.005 + 1.0 - this->counter)*-1.0))/2.3 * this->amount;
+  this->value = max(0.0, (log10(this->snap + 1.0 - this->counter)*-1.0))/2.3 * this->amount;
 }
 
 void EnvelopeSimpleLog::reset() {
@@ -66,6 +68,13 @@ void EnvelopeSimpleLog::setAmount(float amount) {
   this->amount = amount;
 }
 
+void EnvelopeSimpleLog::setSnap(float snap) {
+  this->snap = snap;
+}
+
+
+
+
 // ---- A sigh envelope -------
 class EnvelopeSigh {
   public:
@@ -81,6 +90,7 @@ class EnvelopeSigh {
     void setAmount(float speed);
     void setSpeed(float speed);
     void setDelay(float speed);
+    void setSnap(float snap);
 };
 
 void EnvelopeSigh::update() {

Soft/Drum/Kick.h

@@ -11,6 +11,8 @@ class Kick {
     EnvelopeSimpleLinear volume_envelope;
     EnvelopeSimpleLog pitch_envelope;
     EnvelopeSigh pitch_envelope_sigh;
+    LPF lpf;
+    HPF hpf;
     void setup();
     void update();
     void reset();
@@ -34,6 +36,10 @@ void Kick::setup() {
   }
 
   this->volume_envelope.amount = 1.0;
+  lpf.setFrequency(1000.0);
+  lpf.setResonance(0.99);
+  hpf.setFrequency(30.0);
+  hpf.setResonance(0.5);
 }
 
 void Kick::update() {
@@ -55,7 +61,10 @@ void Kick::trigger() {
 }
 
 float Kick::render() {
-  return this->volume_envelope.value * this->wavetable[(int)this->osc_progress] / 2 + 511;
+  float orig_sample = this->volume_envelope.value * this->wavetable[(int)this->osc_progress];
+  float filtered_sample = hpf.render(lpf.render(orig_sample));
+  float sample = orig_sample*0.75 + filtered_sample*0.2;
+  return sample / 2 + 511;
 }
 
 void Kick::advanceOscillator() {

Soft/Drum/Snare.h

@@ -8,9 +8,11 @@ class Snare {
     float frequency;
     float base_frequency;
     float frequency_range;
-    EnvelopeSimpleLinear volume_envelope;
+    EnvelopeSimpleLog volume_envelope;
     EnvelopeSimpleLog pitch_envelope;
     EnvelopeSigh pitch_envelope_sigh;
+    LPF lpf;
+    HPF hpf;
     void setup();
     void update();
     void reset();
@@ -21,6 +23,8 @@ class Snare {
     void setPitchDecay(float speed);
     void setPitchAmount(float amount);
     void setFrequency(float frequency);
+    void setLpfFrequency(float frequency);
+    void setLpfResonance(float resonance);
 
   private:
     int sinetable[SAMPLES];
@@ -34,11 +38,17 @@ void Snare::setup() {
     this->sinetable[i] = (sin(2 * M_PI * i  / SAMPLES)) * 511;
   }
 
+  // Fill the noise-table with noise
   for (int i = 0; i < SAMPLES; i++) {
     this->noisetable[i] = random(0, 1023);
   }
 
+  // Set some parameters
   this->volume_envelope.amount = 1.0;
+  this->hpf.setFrequency(200.0);
+  this->volume_envelope.setSnap(0.0005);
+  this->pitch_envelope.setSnap(0.0005);
+
 }
 
 void Snare::update() {
@@ -60,7 +70,11 @@ void Snare::trigger() {
 }
 
 float Snare::render() {
-  return this->volume_envelope.value * (this->sinetable[(int)this->osc_progress] + this->pitch_envelope.value * noisetable[(int)this->osc_progress]) / 2 + 511;
+  float orig_sample = this->volume_envelope.value * (this->sinetable[(int)this->osc_progress] + this->pitch_envelope.value * noisetable[(int)this->osc_progress]);
+  // lpf.addFrequency(pitch_envelope.value*500.0);
+  float filtered_sample = hpf.render(lpf.render(orig_sample));
+  float sample = orig_sample/2 + filtered_sample/2;
+  return sample / 2 + 511;
 }
 
 void Snare::advanceOscillator() {
@@ -85,3 +99,11 @@ void Snare::setPitchAmount(float amount) {
 void Snare::setFrequency(float frequency) {
   this->frequency = this->base_frequency + frequency * this->frequency_range;
 }
+
+void Snare::setLpfFrequency(float frequency) {
+  this->lpf.setFrequency(frequency);
+}
+
+void Snare::setLpfResonance(float resonance) {
+  this->lpf.setResonance(resonance);
+}
\ No newline at end of file