Fixing sound pops when changing audio mixers volumes at runtime

Unity Audio is a bit cryptic, and changing volumes often results in artifacts (pops). The following function attached to an SR_Sound script on my SoundController game object fixes it. You can use the same technique with audio sources too, but those are a bit less cryptic. I will include that as well.

Code (CSharp):

1.  
2. AudioMixer SoundMixer = SoundController.GetComponent<SR_Sound>().Mixer;
3. StartCoroutine(SR_Sound.MixerSetVolume(SoundMixer, "Thrusters", 30f));
4.  

Code (CSharp):

1.  
2. //to avoid annoying clicks in audio mixer volume changes
3.     public static IEnumerator MixerSetVolume(AudioMixer _Mixer, string _WhichExposedParam, float _Vol = 0.001f, float _FadeLength = 0.1f)
4.     {
5.         //Debug.Log("Fading out soundfile" + _AudioSource.name);
6.  
7.         if(_Vol == 0f) { _Vol = 0.001f; }
8.  
9.         float _StartVolume;
10.         bool __IsMixerParamExposed = _Mixer.GetFloat(_WhichExposedParam, out _StartVolume);
11.         Extensions.Log(_WhichExposedParam + " mixer = " + _StartVolume);
12.         float _EndVolume = _Vol;
13.  
14.         float _StartTime = Time.time;
15.  
16.         if (_StartVolume > _EndVolume)
17.         {
18.             while (Time.time < _StartTime + _FadeLength)
19.             {
20.                 _Mixer.SetFloat(_WhichExposedParam, _StartVolume - ((_StartVolume - _EndVolume) * ((Time.time - _StartTime) / _FadeLength)));
21.                 yield return null;
22.             }
23.         }
24.         else
25.         {
26.             while (Time.time < _StartTime + _FadeLength)
27.             {
28.                 _Mixer.SetFloat(_WhichExposedParam, _StartVolume + ((_EndVolume - _StartVolume) * ((Time.time - _StartTime) / _FadeLength)));
29.                 yield return null;
30.             }
31.         }
32.  
33.     }
34.  

To tame Audio Sources:

Code (CSharp):

1. public static IEnumerator VolumeFadeOut(AudioSource _AudioSource, float _FadeLength = 0.1f)
2.     {
3.         //Debug.Log("Fading out soundfile" + _AudioSource.name);
4.  
5.         if (MasterVolume == 0f) { yield break; }
6.  
7.         float _StartVolume = _AudioSource.volume;
8.         float _EndVolume = 0f;
9.         float _StartTime = Time.time;
10.         while (Time.time < _StartTime + _FadeLength)
11.         {
12.             _AudioSource.volume = _StartVolume + ((_EndVolume - _StartVolume) * ((Time.time - _StartTime) / _FadeLength));
13.             yield return null;
14.         }
15.         if (_EndVolume == 0) { _AudioSource.Stop(); }
16.     }
17.  
18.     public static IEnumerator VolumeFadeIn(AudioSource _AudioSource, float _EndVolume, float _FadeLength = 0.1f)
19.     {
20.         //Debug.Log("Fading in soundfile"+_AudioSource.name);
21.  
22.         if (MasterVolume == 0f) { yield break; }
23.  
24.         _AudioSource.volume = 0f;
25.         _AudioSource.Play();
26.         float _StartVolume = 0f;
27.         float _StartTime = Time.time;
28.         while (Time.time < _StartTime + _FadeLength)
29.         {
30.             _AudioSource.volume = _StartVolume + ((_EndVolume - _StartVolume) * ((Time.time - _StartTime) / _FadeLength));
31.             yield return null;
32.         }
33.     }

 

Aren't these coroutines? I think you gotta StartCoroutine them or not much will happen...

 

bah! you are right!

 

If I only had a dollar for every time I inadvertently "called" a coroutine without handing it off to StartCoroutine()...

 

Come to think of it, it really should be a compiler warning. I don't think there can be any side effects from simply creating an IEnumerator and doing nothing with it... it's truly just a no-op and unlikely to be what the engineer intended.