diff --git a/MicroDexed.ino b/MicroDexed.ino
index 1f5414b..3f0bb01 100644
--- a/MicroDexed.ino
+++ b/MicroDexed.ino
@@ -62,7 +62,7 @@ USBHost usb_host;
 MIDIDevice midi_usb(usb_host);
 #endif
 
-#ifdef TEST_MIDI
+#ifdef TEST_NOTE
 IntervalTimer sched_note_on;
 IntervalTimer sched_note_off;
 uint8_t _voice_counter = 0;
@@ -120,7 +120,7 @@ void setup()
   Serial.print(F("AUDIO_BLOCK_SAMPLES="));
   Serial.println(AUDIO_BLOCK_SAMPLES);
 
-#ifdef TEST_MIDI
+#ifdef TEST_NOTE
   Serial.println(F("MIDI test enabled"));
   sched_note_on.begin(note_on, 2000000);
   sched_note_off.begin(note_off, 6333333);
@@ -129,7 +129,7 @@ void setup()
   Serial.println(F("setup end"));
   show_cpu_and_mem_usage();
 
-#ifdef TEST_MIDI
+#ifdef TEST_NOTE
   //dexed->data[DEXED_VOICE_OFFSET+DEXED_LFO_PITCH_MOD_DEP] = 99;           // full pitch mod depth
   //dexed->data[DEXED_VOICE_OFFSET+DEXED_LFO_PITCH_MOD_SENS] = 99;          // full pitch mod sense
   //dexed->data[DEXED_GLOBAL_PARAMETER_OFFSET+DEXED_MODWHEEL_ASSIGN] = 7;   // mod wheel assign all
@@ -202,7 +202,7 @@ void handle_midi_input(void)
   }
 }
 
-#ifdef TEST_MIDI
+#ifdef TEST_NOTE
 void note_on(void)
 {
   randomSeed(analogRead(A0));
@@ -254,13 +254,13 @@ void note_off(void)
 #ifdef SHOW_MIDI_EVENT
 void print_midi_event(uint8_t type, uint8_t data1, uint8_t data2)
 {
-  Serial.print("MIDI event type: 0x");
+  Serial.print(F("MIDI event type: 0x"));
   if (type < 16)
     Serial.print(F("0"));
   Serial.print(type, HEX);
-  Serial.print(" data1: ");
+  Serial.print(F(" data1: "));
   Serial.print(data1, DEC);
-  Serial.print(" data2: ");
+  Serial.print(F(" data2: "));
   Serial.println(data2, DEC);
 }
 #endif
diff --git a/config.h b/config.h
index 31293cd..c7b9c88 100644
--- a/config.h
+++ b/config.h
@@ -21,36 +21,41 @@
    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 
 */
-#include "midinotes.h"
 
-//#define TEST_MIDI 1
-#define TEST_NOTE MIDI_E2
-#define TEST_VEL_MIN 60
-#define TEST_VEL_MAX 110
+#include "midinotes.h"
 
-//#define SHOW_DEXED_TIMING 1
-#define DEBUG 1
-#define SERIAL_SPEED 38400
+// Initial values
 #define VOLUME 0.1
 #define SAMPLE_RATE 44100
 //#define DEXED_ENGINE DEXED_ENGINE_MODERN
 #define USE_ONBOARD_USB_HOST 1
-#define SHOW_MIDI_EVENT 1
-#define SHOW_XRUN 1
-#define SHOW_CPU_LOAD_MSEC 5000
 #define MAX_NOTES 16
 #define AUDIO_MEM 2
-
 #define DEFAULT_SYSEXBANK 0
 #define DEFAULT_SYSEXSOUND 0
 
+// Master key handling (comment out for disabling)
 #define MASTER_KEY_MIDI MIDI_C6
 #define MASTER_NUM1 MIDI_C1
 
+// Debug output
+#define SERIAL_SPEED 38400
+//#define SHOW_DEXED_TIMING 1
+#define DEBUG 1
+#define SHOW_MIDI_EVENT 1
+#define SHOW_XRUN 1
+#define SHOW_CPU_LOAD_MSEC 5000
+
+// Some optimizations in the code
 #define USE_TEENSY_DSP 1
 #define SUM_UP_AS_INT 1
 #define REDUCE_LOUDNESS 2
 
+// Enable TEST_NOTE for adding code to drop some midi notes for testing without keyboard
+//#define TEST_NOTE MIDI_E2
+#define TEST_VEL_MIN 60
+#define TEST_VEL_MAX 110
+
 // Use these with the Teensy Audio Shield
 #define SDCARD_CS_PIN    10
 #define SDCARD_MOSI_PIN  7
diff --git a/dexed.cpp b/dexed.cpp
index 0fa453b..9539320 100644
--- a/dexed.cpp
+++ b/dexed.cpp
@@ -158,20 +158,18 @@ void Dexed::getSamples(uint16_t n_samples, int16_t* buffer)
 #else
           int32_t clip_val = val < -(1 << 24) ? 0x8000 : val >= (1 << 24) ? 0x7fff : val >> 9;
 #endif
-          if (clip_val != (val>>9))
-            overload++;
 #ifdef SUM_UP_AS_INT
           sum = buffer[i + j] + (clip_val >> REDUCE_LOUDNESS);
-/*
           if (buffer[i + j] > 0 && clip_val > 0 && sum < 0)
           {
-            sum = 0x8000;
+            sum = INT_MAX;
+            overload++;
           }
           else if (buffer[i + j] < 0 && clip_val < 0 && sum > 0)
           {
-            sum = 0x7FFF;
+            sum = INT_MIN;
+            overload++;
           }
-          */
           buffer[i + j] = sum;
           audiobuf.get()[j] = 0;
 #else
diff --git a/dexed_sysex.cpp b/dexed_sysex.cpp
index f43a26d..f88e526 100644
--- a/dexed_sysex.cpp
+++ b/dexed_sysex.cpp
@@ -70,11 +70,11 @@ bool load_sysex(uint8_t bank, uint8_t voice_number)
           {
             char n[11];
             strncpy(n, (char*)&data[118], 10);
-            Serial.print("<");
+            Serial.print(F("<"));
             Serial.print(entry.name());
-            Serial.print("|'");
+            Serial.print(F("|'"));
             Serial.print(n);
-            Serial.println("'>");
+            Serial.println(F("'>"));
             return (dexed->loadSysexVoice(data));
           }
           else