--- a/dom/media/encoder/MediaEncoder.cpp
+++ b/dom/media/encoder/MediaEncoder.cpp
@@ -534,17 +534,23 @@ MediaEncoder::ConnectMediaStreamTrack(Me
       return;
     }
     if (!mAudioListener) {
       MOZ_ASSERT(false, "No audio listener for this audio track");
       return;
     }
 
     mAudioTrack = audio;
-    audio->AddDirectListener(mAudioListener);
+    // With full duplex we don't risk having audio come in late to the MSG
+    // so we won't need a direct listener.
+    const bool enableDirectListener =
+      !Preferences::GetBool("media.navigator.audio.full_duplex", false);
+    if (enableDirectListener) {
+      audio->AddDirectListener(mAudioListener);
+    }
     audio->AddListener(mAudioListener);
   } else if (VideoStreamTrack* video = aTrack->AsVideoStreamTrack()) {
     if(!mVideoEncoder) {
       MOZ_ASSERT(false, "No video encoder for this video track");
       return;
     }
     if (mVideoTrack) {
       MOZ_ASSERT(false, "Only one video track supported.");