diff --git a/config.sample.h b/config.sample.h
index e9b97dc..2801cd3 100644
--- a/config.sample.h
+++ b/config.sample.h
@@ -27,4 +27,14 @@ uint8_t config_brightness = 20; // Can be overwritten via MQTT_TOPIC_BRIGHTNESS
 
 #define FPS 50
 #define SHOW_TEXT_DELAY 100
+
+// Effect config
 uint16_t config_effect_cycle_time = 300; // Time in seconds between cycling effects.
+
+uint16_t config_effect_matrix_length_min = 4;
+uint16_t config_effect_matrix_length_max = 20;
+uint16_t config_effect_matrix_speed_min = 50;
+uint16_t config_effect_matrix_speed_max = 135;
+
+uint16_t config_effect_single_dynamic_loop_time = 200;
+uint16_t config_effect_multi_dynamic_loop_time = 1400;
diff --git a/effects.h b/effects.h
index c5df912..a455ad7 100644
--- a/effects.h
+++ b/effects.h
@@ -272,7 +272,7 @@ class SingleDynamic : public Effect {
   protected:
     static const int factor = 2;
     static const int tile_count = LED_WIDTH/factor * LED_HEIGHT/factor;
-    virtual int getLoopTime() { return 200; }
+    virtual int getLoopTime() { return config_effect_single_dynamic_loop_time; }
     CRGB tiles[tile_count];
     CRGB old_tiles[tile_count];
     uint8_t blend = 0;
@@ -281,7 +281,7 @@ class SingleDynamic : public Effect {
       for (int i=0; i<tile_count; i++) tiles[i] = CHSV(random8(), 180, 255);
     }
     virtual void update() {
-      tiles[random8() % tile_count] = CHSV(random8(), 180, 255);
+      tiles[random8(tile_count)] = CHSV(random8(), 180, 255);
     }
     boolean can_be_shown_with_clock() { return true; }
     virtual void loop() {
@@ -301,7 +301,7 @@ class SingleDynamic : public Effect {
 
 class MultiDynamic : public SingleDynamic {
   protected:
-    virtual int getLoopTime() { return 1400; }
+    int getLoopTime() { return config_effect_multi_dynamic_loop_time; }
   public:
     void update() {
       for (int i=0; i<tile_count; i++) tiles[i] = CHSV(random8(), 180, 255);
@@ -321,14 +321,15 @@ class MatrixColumn {
     MatrixColumn(Window* win, int xPos) {
       window = win;
       x = xPos;
-      running = false;
+      start();
+      y = random8(0, win->h);
     }
 
     void start() {
       y=-1;
-      length = random8()%16+4;
+      length = random8(config_effect_matrix_length_min, config_effect_matrix_length_max);
       running = true;
-      speed = random8()/3 + 50;
+      speed = random8(config_effect_matrix_speed_min, config_effect_matrix_speed_max);
     }
 
     void advance() {