diff --git a/gba_memory.c b/gba_memory.c
index 2cb760a..7675bb0 100644
--- a/gba_memory.c
+++ b/gba_memory.c
@@ -199,7 +199,7 @@ static void sound_control_x(u32 value)
 
 #define sound_update_frequency_step(timer_number)                             \
   timer[timer_number].frequency_step =                                        \
-   float_to_fp8_24(GBC_BASE_RATE / (timer_reload * sound_frequency))          \
+   float_to_fp8_24((GBC_BASE_RATE / sound_frequency) / (timer_reload))        \
 
 /* Main */
 extern timer_type timer[4];
diff --git a/sound.c b/sound.c
index 126fb5d..10a3261 100644
--- a/sound.c
+++ b/sound.c
@@ -273,8 +273,11 @@ u32 gbc_sound_master_volume;
       else                                                                    \
         rate = rate + (rate >> gs->sweep_shift);                              \
                                                                               \
-      if(rate > 2048)                                                         \
-        rate = 2048;                                                          \
+      if(rate > 2047) {                                                       \
+        rate = 2047;                                                          \
+        gs->active_flag = 0;                                                  \
+        break;                                                                \
+      }                                                                       \
                                                                               \
       frequency_step = float_to_fp16_16(((131072.0f / (2048 - rate)) * 8.0f)  \
        / sound_frequency);                                                    \