diff --git a/panda/src/audio/audio_null_traits.cxx b/panda/src/audio/audio_null_traits.cxx
index ccb0d4b2b0..a4bf02b6b5 100644
--- a/panda/src/audio/audio_null_traits.cxx
+++ b/panda/src/audio/audio_null_traits.cxx
@@ -76,7 +76,7 @@ NullPlayer::~NullPlayer() {
 }
 
 void NullPlayer::play_sound(AudioTraits::SoundClass*,
-                AudioTraits::PlayingClass*, float) {
+                AudioTraits::PlayingClass*, float, int) {
   if (audio_cat.is_debug())
     audio_cat->debug() << "in play sound in Null audio driver" << endl;
 }
diff --git a/panda/src/audio/audio_null_traits.h b/panda/src/audio/audio_null_traits.h
index d6ccf1012b..8559e34c8f 100644
--- a/panda/src/audio/audio_null_traits.h
+++ b/panda/src/audio/audio_null_traits.h
@@ -52,7 +52,7 @@ public:
   virtual ~NullPlayer();
 
   virtual void play_sound(AudioTraits::SoundClass*,
-                          AudioTraits::PlayingClass*, float);
+                          AudioTraits::PlayingClass*, float, int);
   virtual void stop_sound(AudioTraits::SoundClass*,
                           AudioTraits::PlayingClass*);
   virtual void set_volume(AudioTraits::PlayingClass*, float);