From 4a8d875515e0c76f7a84a9d93ef32b9eec6b5e0a Mon Sep 17 00:00:00 2001
From: Holger Wirtz <wirtz@parasitstudio.de>
Date: Fri, 27 Sep 2019 10:50:41 +0200
Subject: [PATCH] Fix for modulated delay.

---
 MicroMDAEPiano.ino         |  7 ++++++-
 config.h                   |  4 ++--
 effect_modulated_delay.cpp | 12 +++++-------
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/MicroMDAEPiano.ino b/MicroMDAEPiano.ino
index e69770e..05d0e9e 100644
--- a/MicroMDAEPiano.ino
+++ b/MicroMDAEPiano.ino
@@ -239,11 +239,16 @@ void setup()
     Serial.println(F("AudioEffectModulatedDelay - left channel begin failed"));
     while (1);
   }
+#ifdef DEBUG
+  Serial.print(F("MOD_DELAY_SAMPLE_BUFFER="));
+  Serial.print(MOD_DELAY_SAMPLE_BUFFER, DEC);
+  Serial.println(F(" samples"));
+#endif
 
   // chorus modulation fixed
   modulator.begin(MOD_WAVEFORM);
   modulator.phase(0);
-  modulator.amplitude(0.0);
+  modulator.amplitude(0.5);
   modulator.offset(0.0);
 #if MOD_FILTER_OUTPUT == MOD_BUTTERWORTH_FILTER_OUTPUT
   // Butterworth filter, 12 db/octave
diff --git a/config.h b/config.h
index c1a963a..c9256cd 100644
--- a/config.h
+++ b/config.h
@@ -76,7 +76,7 @@
 #define SERIAL_SPEED 38400
 #define SHOW_XRUN 1
 #define SHOW_CPU_LOAD_MSEC 5000
-//#define DEBUG_AUDIO 50
+#define DEBUG_AUDIO 50
 
 //*************************************************************************************************
 //* HARDWARE SETTINGS
@@ -275,7 +275,7 @@
 #define ENC_REVERB_DAMPING_MAX 99
 #define ENC_REVERB_DAMPING_DEFAULT 50
 //
-#define ENC_REVERB_LEVEL_MIN 0
+#define ENC_REVERB_LEVEL_MIN 1
 #define ENC_REVERB_LEVEL_MAX 99
 #define ENC_REVERB_LEVEL_DEFAULT 15
 //
diff --git a/effect_modulated_delay.cpp b/effect_modulated_delay.cpp
index 84bb5bb..d9a1f99 100644
--- a/effect_modulated_delay.cpp
+++ b/effect_modulated_delay.cpp
@@ -50,17 +50,15 @@ boolean AudioEffectModulatedDelay::begin(short *delayline, uint16_t d_length)
   _cb_index = 0;
   _delay_offset = 0;
 
-  if (delayline == NULL) {
+  if (delayline == NULL)
     return (false);
-  }
-  if (d_length < 10) {
+  if (d_length < 10)
     return (false);
-  }
 
   _delayline = delayline;
   _delay_length = d_length;
-  memset(_delayline, 0, _delay_length);
-  _delay_offset = (_delay_length - 1) >> 1;
+  memset(_delayline, 0, _delay_length * sizeof(int16_t));
+  _delay_offset = _delay_length >> 1 ;
 
   return (true);
 }
@@ -107,7 +105,7 @@ void AudioEffectModulatedDelay::update(void)
       mod_fraction = modff(mod_index, &mod_number); // split float of mod_index into integer (= mod_number) and fraction part
 
       // calculate modulation index into circular buffer
-      cb_mod_index = _cb_index - mod_number;
+      cb_mod_index = _cb_index - (_delay_offset + mod_number);
       if (cb_mod_index < 0) // check for negative offsets and correct them
         cb_mod_index += _delay_length;