Audio AudioMixerSnapshot TransitionTo click/pop

Hi all,

I'm using the standard AudioMixerSnapshot TransitionTo() method and am getting a noticeable 'click' or 'pop' in the audio immediately as the method is called.

I've noticed that it also happens when moving an audio mixer fader in the editor. The moment the fader is moved, there is an audible click.

Has anyone else experienced this issue and found a workaround? I feel it may possibly be worth logging as a bug with Unity depending on responses, as I'm not doing anything unusual - an AudioSource playing an AudioClip into an AudioMixer and transitioning to an AudioMixerSnapshot.

I'm using Unity 2017.1.0f3.
I'm using a transition time of just over 1 second.
I'm using a standard linear transition curve (I've tried smoothstep, squared etc. but the click remains).

Thanks,
Andy

 

I've noticed this too - in an earlier version 5.4.2. I was hoping it would be fixed in a more current version, but apparently not yet. I believe this is an audio bug in the Unity audio engine. If you fade the audiosource volumes manually through a script it doesn't click. With the snapshot transitions, it happens about 90% of the time, but occasionally it won't click - and I believe it has to do with whether the audio is going through a zero-cross (e.g. if you hit it on a zero-cross you don't get the click). It seems that lower frequency sounds tend to increase the frequency of how often the click happens.

 

As a followup, if you expose the volume parameters in the Unity Mixer and use a script instead of the snapshot transitions to set the volume - I haven't noticed the clicking.

 

Thanks for the info @msweet37.

I received a reply from the Unity QA team regarding another audio issue, which stated that it would not be fixed now, but in the future, as they are "remaking the audio system". I'm therefore inclined to believe that this issue may fall into the same category and will hopefully be addressed in what sounds like quite a major update to the audio system currently in development.