diff --git a/audio.go b/audio.go
index fbdff99a..ce88f0d4 100644
--- a/audio.go
+++ b/audio.go
@@ -30,9 +30,9 @@ var (
 
 func getAlsaDevice(source string) string {
 	if source == "hdmi" {
-		return "hw:0,0"  // TC358743 HDMI audio
+		return "hw:0,0" // TC358743 HDMI audio
 	}
-	return "hw:1,0"  // USB Audio Gadget
+	return "hw:1,0" // USB Audio Gadget
 }
 
 func initAudio() {
diff --git a/internal/audio/c/audio.c b/internal/audio/c/audio.c
index 0e74d80e..abd286bb 100644
--- a/internal/audio/c/audio.c
+++ b/internal/audio/c/audio.c
@@ -673,10 +673,16 @@ retry_read:
 
 	snd_pcm_t *handle = pcm_capture_handle;
 
-	// Read from hardware at hardware sample rate
+	// Release mutex before blocking I/O to allow clean shutdown
+	pthread_mutex_unlock(&capture_mutex);
+
+	// Read from hardware at hardware sample rate (blocking call, no mutex held)
 	pcm_rc = snd_pcm_readi(handle, pcm_hw_buffer, hardware_frame_size);
 
-	if (handle != pcm_capture_handle) {
+	// Reacquire mutex and verify device wasn't closed during read
+	pthread_mutex_lock(&capture_mutex);
+
+	if (handle != pcm_capture_handle || atomic_load(&capture_stop_requested)) {
 		pthread_mutex_unlock(&capture_mutex);
 		return -1;
 	}
@@ -884,9 +890,17 @@ retry_write:
 	}
 
 	snd_pcm_t *handle = pcm_playback_handle;
+
+	// Release mutex before blocking I/O to allow clean shutdown
+	pthread_mutex_unlock(&playback_mutex);
+
+	// Write to hardware (blocking call, no mutex held)
 	pcm_rc = snd_pcm_writei(handle, pcm_buffer, pcm_frames);
 
-	if (handle != pcm_playback_handle) {
+	// Reacquire mutex and verify device wasn't closed during write
+	pthread_mutex_lock(&playback_mutex);
+
+	if (handle != pcm_playback_handle || atomic_load(&playback_stop_requested)) {
 		pthread_mutex_unlock(&playback_mutex);
 		return -1;
 	}