add these methods to your viewController that's the delegate for adcolony, which should also be the viewcontroller in which you initialize the AVAudioPlayer. I probably don't need to state this, but i'm assuming you have an @Property for your audioPlayer
- (void) onAdColonyAdStartedInZone:(NSString *)zoneID{
self.audioPlayer.volume = 0.0f;
}
- (void) onAdColonyAdAttemptFinished:(BOOL)shown inZone:(NSString *)zoneID{
self.audioPlayer.volume = 1.0f;
}