diff --git a/app/src/main/kotlin/de/rochefort/childmonitor/ListenService.kt b/app/src/main/kotlin/de/rochefort/childmonitor/ListenService.kt
index 2b9619e..5240363 100644
--- a/app/src/main/kotlin/de/rochefort/childmonitor/ListenService.kt
+++ b/app/src/main/kotlin/de/rochefort/childmonitor/ListenService.kt
@@ -160,7 +160,7 @@ class ListenService : Service() {
         lt.start()
     }
 
-    private fun withAudioTrack(block: (AudioTrack) -> Unit): Unit {
+    private fun withAudioTrack(block: (AudioTrack) -> Unit) {
         Log.i(TAG, "Setting up stream")
         val audioTrack = AudioTrack(AudioManager.STREAM_MUSIC,
             frequency,