back to resonant filter (svf doesn't fit the character). reduced gain before filter fixes the overflow issue

Acid/Acid.ino

@@ -7,8 +7,9 @@
 // This code is licenced under GPL v3 or later
 
 // todo:
-// debug accent handling that overloads the filter
+// debug accent handling that overloads the filter, also accent can be too short or too long if it's relying on midi note
 // add overdrive
+// frequency from CV (noteFreq) could be Q16n16 for consistency
 
 #include <Mozzi.h>
 #include <MIDI.h>
@@ -98,12 +99,13 @@ Oscil <SAW_MAX_8192_AT_16384_512_NUM_CELLS, MOZZI_AUDIO_RATE> aSaw8192(SAW_MAX_8
 MetaOscil<SAW_MAX_138_AT_16384_512_NUM_CELLS, MOZZI_AUDIO_RATE, 16> aSaw {&aSaw138, &aSaw154, &aSaw182, &aSaw240, &aSaw292, &aSaw341, &aSaw390, &aSaw431, &aSaw512, &aSaw630, &aSaw744, &aSaw1170, &aSaw1638, &aSaw2730, &aSaw4096, &aSaw8192};
 
 IntMap kMapNote(         0, 4095, 24 * pitchSubSteps, 84 * pitchSubSteps );
-IntMap kMapResonance(    0, 1023, 0,   255   );
 IntMap kMapCutoff(       0, 1023, 26,  100   );
-IntMap kMapAttack(       0, 1023, 3,   100   );
+IntMap kMapEnvMod(       0, 1023, 0,   140   );
-IntMap kMapDecay(        0, 1023, 200, 2000  );
+IntMap kMapResonance(    0, 1023, 0,   255   );
-IntMap kMapEnvMod(       0, 1023, 0,   160   );
 IntMap kMapDrive(        0, 1023, 0,   400   );
+IntMap kMapAttack(       0, 1023, 1,   100   );
+IntMap kMapDecay(        0, 1023, 100, 1500  );
+IntMap kMapAccentLevel(  0, 1023, 0,   128   );
 
 Ead kEnvelope(MOZZI_CONTROL_RATE);
 LowPassFilter lpfr;
@@ -114,7 +116,7 @@ byte gain;
 bool MIDINotePlaying;
 bool MIDINoteFaded = true;
 bool gateIsHigh = false;
-Q16n16 noteFreq;
+float noteFreq;
 bool envSwitchVal;
 bool droneSwitchVal;
 byte MIDIChannel;
@@ -123,11 +125,10 @@ int driveAmount;
 byte notePlaying;
 bool accent = false;
 
-
 void MIDINoteOn(byte channel, byte note, byte velocity) {
   notePlaying = note;
-  noteFreq = Q16n16_mtof((int) note);
 
+  accent = false; //reset if the previous note was accented
   if (velocity >= 127) {
     accent = true;
   }
@@ -150,7 +151,6 @@ void MIDINoteOff(byte channel, byte note, byte velocity) {
   if (note == notePlaying || !droneSwitchVal) {
     MIDINotePlaying = false;
     digitalWrite(LED, HIGH);
-    accent = false;
   }
 }
 
@@ -269,11 +269,14 @@ void updateControl(){
   int CVInVal = mozziAnalogRead(CVIn);
 
   //Remap the values and assign to parameters
-  int cutoff = accent? 100 : kMapCutoff(knob1Val);
+  int accentLevel = kMapAccentLevel(knobSVal);
-  int resonance = accent? 255 : kMapResonance(knob2Val);
+  int baseCutoff = kMapCutoff(knob1Val);
+  int cutoff = accent? (baseCutoff + (((long)accentLevel * (100 - baseCutoff)) >> 7)) : baseCutoff;
+  int resonance = accent? (255 - (((long)(128 - accentLevel) * (255 - kMapResonance(knob2Val))) >> 7)) : kMapResonance(knob2Val);
   int envMod = kMapEnvMod(knob3Val);
   driveAmount = kMapDrive(knob4Val);
   
+
   //Set pitch and play notes on trigger
   if (MIDINoteFaded) {
     noteFreq = mtof((float) kMapNote(CVInVal << 2) / pitchSubSteps);
@@ -288,29 +291,35 @@ void updateControl(){
 
   //Update Envelope Settings
   int attackTime = kMapAttack(knobAVal);
-  int decayReleaseTime = kMapDecay(knobDRVal);
+  int baseDecay = kMapDecay(knobDRVal);
-  kEnvelope.setDecay(accent? 400 : decayReleaseTime);
+  int decayTime = accent? (100 + (((long)(128 - accentLevel) * (baseDecay - 100)) >> 7)) : baseDecay;
-  kEnvelope.setAttack(accent? 3 : attackTime);
+  kEnvelope.setDecay(decayTime);
+  kEnvelope.setAttack(accent? 1 : attackTime);
 
   //Calculate makeup Gain
-  //makeupGain = (256L * 127) / (127 + driveAmount); // Q8 fixed-point compensation factor
+  //makeupGain = ((long)256 * 127) / (127 + driveAmount);
 
   //Set Oscilator Frequency
   Q16n16 oscFreq;
+  if (!MIDINoteFaded) {
     oscFreq = kGlide.next();
     aSquare.setFreq_Q16n16(oscFreq);
     aSaw.setFreq_Q16n16(oscFreq);
+  } else {
+    aSquare.setFreq(noteFreq);
+    aSaw.setFreq(noteFreq);
+  }
   
   int env = kEnvelope.next();
 
-  if (!MIDINotePlaying && !MIDINoteFaded && env == 0) { //threshhold might need adjustment
+  if (!MIDINotePlaying && !MIDINoteFaded && env == 0) {
     MIDINoteFaded = true;
+    accent = false;
   }
 
-  gain = accent? env * 2 : env;
+  gain = accent? constrain(env + (((long)env * accentLevel) >> 7), 0, 255) : env; //needs finetuning
 
   lpfr.setCutoffFreqAndResonance(constrain(cutoff + (((long)env * envMod * cutoff)>>16), 0, 255), resonance);
-
 }
 
 AudioOutput updateAudio(){
@@ -320,8 +329,9 @@ AudioOutput updateAudio(){
   } else {
     signal = aSaw.next();
   }
+  signal = signal >> 2; //lowering the gain before filter to avoid filter overflow bug
   signal = lpfr.next(signal); //filter
-  signal = (signal * gain); //envelope
+  signal = (signal * gain) << 2; //envelope
   //signal = softClip((signal * (127 + driveAmount)) >> 9); //overdrive
   //signal = (signal * makeupGain) >> 7; //makeup gain compensation
 

Acid/config.h

@@ -4,13 +4,13 @@ const int pitchSubSteps = 16; //set how many steps are there between semitones.
 #define GLIDE_TIME 60
 
 //Hardware Definitions
-#define Knob1   A6  //Intensity
+#define Knob1   A6  //Cutoff
-#define Knob2   A4  //Modulator frequency ratio/Harmonics
+#define Knob2   A4  //Resonance
-#define Knob3   A2  //LFO Frequency
+#define Knob3   A2  //Env.Mod
-#define Knob4   A0  //LFO Shape
+#define Knob4   A0  //Overdrive
 #define KnobA   A5  //Attack
-#define KnobDR  A3  //Decay and Release
+#define KnobDR  A3  //Decay
-#define KnobS   A1  //Sustain
+#define KnobS   A1  //Accent
 #define CVIn    A7  //CV input and Pitch knob
 #define GateIn  10
 #define EnvSwitch 11