Several fixes for avoiding distortion.

MicroDexed.ino

@@ -300,11 +300,11 @@ void setup()
 #ifdef SGTL5000_AUDIO_ENHANCE
   sgtl5000_1.audioPostProcessorEnable();
   sgtl5000_1.enhanceBassEnable();
-  sgtl5000_1.enhanceBass(1.0, 1.0); // enhanceBass(1.0, 1.0, 1, 2); // Configures the bass enhancement by setting the levels of the original stereo signal and the bass-enhanced mono level which will be mixed together. The high-pass filter may be enabled (0) or bypassed (1).
-  sgtl5000_1.surroundSound(7, 3); // Configures virtual surround width from 0 (mono) to 7 (widest). select may be set to 1 (disable), 2 (mono input) or 3 (stereo input).
+  sgtl5000_1.enhanceBass(1.0, 1.5); // enhanceBass(1.0, 1.0, 1, 2); // Configures the bass enhancement by setting the levels of the original stereo signal and the bass-enhanced mono level which will be mixed together. The high-pass filter may be enabled (0) or bypassed (1).
   sgtl5000_1.surroundSoundEnable();
-  sgtl5000_1.autoVolumeControl(1, 1, 1, 0.9, 0.01, 0.05);
+  sgtl5000_1.surroundSound(7, 3); // Configures virtual surround width from 0 (mono) to 7 (widest). select may be set to 1 (disable), 2 (mono input) or 3 (stereo input).
   sgtl5000_1.autoVolumeEnable();
+  sgtl5000_1.autoVolumeControl(1, 1, 1, 0.9, 0.01, 0.05);
   /* The cutoff frequency is specified as follows:
     value  frequency
     0      80Hz

config.h

@@ -80,7 +80,7 @@
 //*************************************************************************************************
 //* DEBUG OUTPUT SETTINGS
 //*************************************************************************************************
-//#define DEBUG 1
+#define DEBUG 1
 #define SERIAL_SPEED 230400
 #define SHOW_XRUN 1
 #define SHOW_CPU_LOAD_MSEC 5000
@@ -93,8 +93,8 @@
 // CHORUS parameters
 #define MOD_DELAY_SAMPLE_BUFFER int32_t(TIME_MS2SAMPLES(20.0)) // 20.0 ms delay buffer. 
 #define MOD_WAVEFORM WAVEFORM_TRIANGLE // WAVEFORM_SINE WAVEFORM_TRIANGLE WAVEFORM_SAWTOOTH WAVEFORM_SAWTOOTH_REVERSE
-#define MOD_FILTER_OUTPUT MOD_LINKWITZ_RILEY_FILTER_OUTPUT // MOD_LINKWITZ_RILEY_FILTER_OUTPUT MOD_BUTTERWORTH_FILTER_OUTPUT MOD_NO_FILTER_OUTPUT
-#define MOD_FILTER_CUTOFF_HZ 15
+#define MOD_FILTER_OUTPUT MOD_BUTTERWORTH_FILTER_OUTPUT // MOD_LINKWITZ_RILEY_FILTER_OUTPUT MOD_BUTTERWORTH_FILTER_OUTPUT MOD_NO_FILTER_OUTPUT
+#define MOD_FILTER_CUTOFF_HZ 2000
 // FX-CHAIN ENABLE/DISABLE
 #define USE_FX 1
 #define SGTL5000_AUDIO_ENHANCE 1
@@ -103,13 +103,11 @@
 //* AUDIO SOFTWARE SETTINGS
 //*************************************************************************************************
 #ifndef TEENSY_AUDIO_BOARD
-#define REDUCE_LOUDNESS 0
 #if AUDIO_BLOCK_SAMPLES == 64
 #define AUDIO_MEM 512
 #else
 #define AUDIO_MEM 384
 #endif
-#define REDUCE_LOUDNESS 0
 #else // IF TEENSY_AUDIO_BOARD
 /*
   13: 3.16 Volts p-p
@@ -286,7 +284,6 @@
 
 // Audio
 #ifdef TGA_AUDIO_BOARD
-#define REDUCE_LOUDNESS 0
 #endif
 
 // Some optimizations

dexed.cpp

@@ -147,7 +147,8 @@ void Dexed::getSamples(uint16_t n_samples, int16_t* buffer)
 
         for (j = 0; j < _N_; ++j)
         {
-          sumbuf[i + j] += static_cast<float>(signed_saturate_rshift(audiobuf.get()[j] >> 4, 24, 9)) / 0x8000;
+          //sumbuf[i + j] += static_cast<float>(signed_saturate_rshift(audiobuf.get()[j] >> 4, 24, 9)) / 0x8000;
+          sumbuf[i + j] += static_cast<float>(signed_saturate_rshift(audiobuf.get()[j] >> 5, 24, 9)) / 0x8000;
           audiobuf.get()[j] = 0;
         }
       }