diff --git a/agb/src/sound/mixer/sw_mixer.rs b/agb/src/sound/mixer/sw_mixer.rs
index 3aac9438..dc6b3629 100644
--- a/agb/src/sound/mixer/sw_mixer.rs
+++ b/agb/src/sound/mixer/sw_mixer.rs
@@ -337,7 +337,7 @@ const fn mod3_estimate(x: usize) -> usize {
 
 impl MixerBufferState {
     fn should_calculate(&self) -> bool {
-        mod3_estimate(self.active_buffer + 1) != mod3_estimate(self.playing_buffer)
+        mod3_estimate(self.active_buffer + 1) != self.playing_buffer
     }
 
     fn playing_advanced(&mut self) -> usize {