diff --git a/src/output/plugins/OSXOutputPlugin.cxx b/src/output/plugins/OSXOutputPlugin.cxx
index 38a020021..540d342f9 100644
--- a/src/output/plugins/OSXOutputPlugin.cxx
+++ b/src/output/plugins/OSXOutputPlugin.cxx
@@ -618,15 +618,17 @@ osx_output_play(AudioOutput *ao, const void *chunk, size_t size,
 {
 	OSXOutput *od = (OSXOutput *)ao;
 
-	od->mutex.lock();
-	while (true) {
-		if (od->ring_buffer->write_available() > 0)
-			break;
+	{
+		const ScopeLock protect(od->mutex);
 
-		/* wait for some free space in the buffer */
-		od->condition.wait(od->mutex);
+		while (true) {
+			if (od->ring_buffer->write_available() > 0)
+				break;
+
+			/* wait for some free space in the buffer */
+			od->condition.wait(od->mutex);
+		}
 	}
-	od->mutex.unlock();
 
 	return od->ring_buffer->push((uint8_t *) chunk, size);
 }