diff --git a/docs/controls.md b/docs/controls.md
index e5bb3f90..111c9ed5 100644
--- a/docs/controls.md
+++ b/docs/controls.md
@@ -21,3 +21,5 @@ On mobile platforms (iOS, Android), web views do not reliably support selecting
   This button is only shown on iOS. (`userAgent.includes("iPhone")`)
 - `controls.onAudioPlaybackStarted: ((id: string) => void) | undefined`: This will be called the first time we start
   playing audio in the webview. It can be helpful to do device setup on the native app when the webviews audio is ready.
+  In particular android is using it to setup the output channel so that the call volume can
+  be controlled by the hardware volume rocker.