diff --git a/MicroMDAEPiano.ino b/MicroMDAEPiano.ino
index 4c94684..7fceb66 100644
--- a/MicroMDAEPiano.ino
+++ b/MicroMDAEPiano.ino
@@ -28,7 +28,7 @@
 #include <EEPROM.h>
 #include "EEPROMAnything.h"
 #include "mdaEPiano.h"
-#include "effect_modulated_chorus.h"
+#include "effect_modulated_delay.h"
 #ifdef USE_XFADE_DATA
 #include "mdaEPianoDataXfade.h"
 #else
@@ -243,12 +243,12 @@ void setup()
   modulator.offset(0.0);
 
   // internal mixing of original signal(0), reverb(1) and chorus(2)
-  mixer_r.gain(0, 1.0);
-  mixer_l.gain(0, 1.0);
-  mixer_r.gain(1, 0.5);
-  mixer_l.gain(1, 0.5);
-  mixer_r.gain(2, 0.5);
-  mixer_l.gain(2, 0.5);
+  mixer_r.gain(0, 0.0);
+  mixer_l.gain(0, 0.0);
+  mixer_r.gain(1, 0.0);
+  mixer_l.gain(1, 0.0);
+  mixer_r.gain(2, 1.0);
+  mixer_l.gain(2, 1.0);
 
   // set master volume
   set_master_volume(master_volume);
diff --git a/config.h b/config.h
index f347948..cfb040e 100644
--- a/config.h
+++ b/config.h
@@ -63,7 +63,7 @@
 // CHORUS parameters
 #define INTERPOLATION_WINDOW_SIZE 7 // For chorus, only odd numbers,please!
 #define INTERPOLATE QUADRATIC // LINEAR QUADRATIC COSINE CUBIC LAGRANGE 
-#define CHORUS_WAVEFORM WAVEFORM_TRIANGLE // WAVEFORM_SINE WAVEFORM_SAWTOOTH WAVEFORM_SAWTOOTH_REVERSE WAVEFORM_SQUARE WAVEFORM_TRIANGLE
+#define CHORUS_WAVEFORM WAVEFORM_SINE // WAVEFORM_SINE WAVEFORM_SAWTOOTH WAVEFORM_SAWTOOTH_REVERSE WAVEFORM_SQUARE WAVEFORM_TRIANGLE
 #define CHORUS_DELAY_LENGTH (16*AUDIO_BLOCK_SAMPLES)
 
 //*************************************************************************************************
diff --git a/effect_modulated_chorus.cpp b/effect_modulated_delay.cpp
similarity index 81%
rename from effect_modulated_chorus.cpp
rename to effect_modulated_delay.cpp
index 6f18de6..32769b4 100644
--- a/effect_modulated_chorus.cpp
+++ b/effect_modulated_delay.cpp
@@ -23,7 +23,7 @@
 
 #include <Arduino.h>
 #include "limits.h"
-#include "effect_modulated_chorus.h"
+#include "effect_modulated_delay.h"
 #include "interpolation.h"
 #include "config.h"
 
@@ -33,7 +33,7 @@
 // Written by Pete (El Supremo) Jan 2014
 // 140529 - change to handle mono stream - change modify() to voices()
 // 140219 - correct storage class (not static)
-// 190527 - added modulation input handling (by Holger Wirtz)
+// 190527 - added modulation input (by Holger Wirtz)
 
 boolean AudioEffectModulatedDelay::begin(short *delayline, int d_length)
 {
@@ -90,9 +90,6 @@ void AudioEffectModulatedDelay::update(void)
   modulation_interpolate.valuelenXY(INTERPOLATION_WINDOW_SIZE);
   modulation_interpolate.valueX(x);
   modulation_interpolate.valueY(y);
-
-  for (j = 0; j < INTERPOLATION_WINDOW_SIZE; j++)
-    x[j] = float(j);
 #endif
 
   bp = block->data;
@@ -108,24 +105,24 @@ void AudioEffectModulatedDelay::update(void)
       _delayline[_circ_idx] = *bp;
 
       // calculate modulation index
-      mod_idx = float(*mp) / SHRT_MAX * _delay_length_half + _circ_idx; // calculate index with modulation as a float(!!!)
-      if (mod_idx > float(_delay_length - 1))
-        mod_idx = mod_idx - float(_delay_length - 1);
-      else if (mod_idx < 0.0)
-        mod_idx = float(_delay_length - 1) + mod_idx;
+      mod_idx = float(*mp) / SHRT_MAX * _delay_length_half; // calculate index with modulation as a float(!!!)
 
 #ifdef INTERPOLATE
       // get x/y values around mod_idx
       uint8_t c = 0;
+      int16_t c_mod_idx = int(mod_idx + 0.5) + _circ_idx;
       for (j = INTERPOLATION_WINDOW_SIZE / -2; j <= INTERPOLATION_WINDOW_SIZE / 2; j++)
       {
-        y[c] = float(_delayline[(int(mod_idx + 0.5) + _circ_idx + j) % _delay_length]);
-        if (y[c] < 0)
-          y[c] = _delay_length + y[c];
+        int16_t jc_mod_idx = (c_mod_idx + j) % _delay_length;
+        if (jc_mod_idx < 0)
+          y[c] = float(_delayline[_delay_length + jc_mod_idx]);
+        else
+          y[c] = float(_delayline[jc_mod_idx]);
+        x[c] = float(c);
         c++; // because 42 is the answer! ;-)
       }
 
-      modulation_interpolate.valueI(mod_idx);
+      modulation_interpolate.valueI(mod_idx - int(mod_idx + 0.5));
 
 #if INTERPOLATE == CUBIC
       *bp = int(modulation_interpolate.CubicInterpolate() + 0.5);
@@ -139,11 +136,19 @@ void AudioEffectModulatedDelay::update(void)
       *bp = int(modulation_interpolate.QuadraticInterpolate() + 0.5);
 #else
       // No interpolation - should sound really bad...
-      *bp = _delayline[int(mod_idx + 0.5)];
+      int16_t c_mod_idx = int(mod_idx + 0.5) + _circ_idx;
+      if (c_mod_idx < 0)
+        *bp = _delayline[_delay_length + c_mod_idx];
+      else
+        *bp = _delayline[c_mod_idx];
 #endif
 #else
       // No interpolation - should sound really bad...
-      *bp = _delayline[int(mod_idx + 0.5)];
+      int16_t c_mod_idx = int(mod_idx + 0.5) + _circ_idx;
+      if (c_mod_idx < 0)
+        *bp = _delayline[_delay_length + c_mod_idx];
+      else
+        *bp = _delayline[c_mod_idx];
 #endif
 
       bp++;
diff --git a/effect_modulated_chorus.h b/effect_modulated_delay.h
similarity index 100%
rename from effect_modulated_chorus.h
rename to effect_modulated_delay.h