diff --git a/MicroDexed.ino b/MicroDexed.ino
index 13e9de0..a79689c 100644
--- a/MicroDexed.ino
+++ b/MicroDexed.ino
@@ -119,6 +119,7 @@ uint8_t effect_delay_time = 0;
 uint8_t effect_delay_feedback = 0;
 uint8_t effect_delay_volume = 0;
 bool effect_delay_sync = 0;
+elapsedMicros fill_audio_buffer;
 
 #ifdef MASTER_KEY_MIDI
 bool master_key_enabled = false;
@@ -332,16 +333,18 @@ void setup()
 void loop()
 {
   int16_t* audio_buffer; // pointer to AUDIO_BLOCK_SAMPLES * int16_t
-  const uint16_t audio_block_time_ms = 1000000 / (SAMPLE_RATE / AUDIO_BLOCK_SAMPLES);
+  const uint16_t audio_block_time_us = 1000000 / (SAMPLE_RATE / AUDIO_BLOCK_SAMPLES);
 
   // Main sound calculation
-  if (queue1.available())
+  if (queue1.available() && fill_audio_buffer > audio_block_time_us - 10)
   {
+    fill_audio_buffer = 0;
+
     audio_buffer = queue1.getBuffer();
 
     elapsedMicros t1;
     dexed->getSamples(AUDIO_BLOCK_SAMPLES, audio_buffer);
-    if (t1 > audio_block_time_ms) // everything greater 2.9ms is a buffer underrun!
+    if (t1 > audio_block_time_us) // everything greater 2.9ms is a buffer underrun!
       xrun++;
     if (t1 > render_time_max)
       render_time_max = t1;
@@ -366,6 +369,7 @@ void loop()
 
   // MIDI input handling
   handle_input();
+
 #ifdef I2C_DISPLAY
   // UI
   if (master_timer >= TIMER_UI_HANDLING_MS)
@@ -654,6 +658,7 @@ bool queue_midi_event(uint8_t type, uint8_t data1, uint8_t data2)
             mixer2.gain(1, mapfloat(effect_delay_volume, 0, ENC_DELAY_VOLUME_STEPS, 0.0, 1.0)); // delay tap1 signal (with added feedback)
             break;
           default:
+            ret = dexed->processMidiMessage(type, data1, data2);
             break;
         }
       }
diff --git a/UI.cpp b/UI.cpp
index 5aa2abb..9c878f2 100644
--- a/UI.cpp
+++ b/UI.cpp
@@ -74,6 +74,7 @@ void handle_ui(void)
 #ifdef DEBUG
         Serial.print(F("Long button pressing detected for button "));
         Serial.println(i, DEC);
+#endif
 
         switch (i)
         {
@@ -103,7 +104,6 @@ void handle_ui(void)
             }
             break;
         }
-#endif
       }
       else
       {
@@ -559,7 +559,7 @@ void ui_show_effects_delay(void)
     lcd.show(1, 8, 5, "Vol:");
   }
 
-  lcd.show(0, 9, 4, map(effect_delay_time, 0, ENC_DELAY_TIME_STEPS, 0, 1200));
+  lcd.show(0, 9, 4, map(effect_delay_time, 0, ENC_DELAY_TIME_STEPS, 0, DELAY_MAX_TIME));
   lcd.show(1, 4, 2, map(effect_delay_feedback, 0, ENC_DELAY_FB_STEPS, 0, 99));
   lcd.show(1, 13, 2, map(effect_delay_volume, 0, ENC_DELAY_VOLUME_STEPS, 0, 99));
 
diff --git a/config.h b/config.h
index 3f6ebf0..dd2d6db 100644
--- a/config.h
+++ b/config.h
@@ -44,8 +44,10 @@
 //#define DEXED_ENGINE DEXED_ENGINE_MODERN
 #ifndef TEENSY_AUDIO_BOARD
 #define AUDIO_MEM 450
+#define DELAY_MAX_TIME 600.0
 #else
 #define AUDIO_MEM 900
+#define DELAY_MAX_TIME 1200.0
 #endif
 #define SAMPLE_RATE 44100
 #define MAX_BANKS 100
@@ -62,7 +64,6 @@
 
 // EFFECTS
 #define FILTER_MAX_FREQ 10000
-#define DELAY_MAX_TIME 1200.0
 
 // Master key handling (comment for disabling)
 //#define MASTER_KEY_MIDI MIDI_C7
@@ -70,7 +71,7 @@
 
 // Debug output
 #define SERIAL_SPEED 38400
-#define DEBUG 1
+//#define DEBUG 1
 #define SHOW_MIDI_EVENT 1
 #define SHOW_XRUN 1
 #define SHOW_CPU_LOAD_MSEC 5000
diff --git a/doc/MicroDexed_Latency.png b/doc/MicroDexed_Latency.png
new file mode 100644
index 0000000..fc5301d
Binary files /dev/null and b/doc/MicroDexed_Latency.png differ