Playing the same sfx multiple times, sometimes one source is louder then the others

I wanted to play with some new features in 2017.1 (Physics.Simulate) and after getting that working and upgrading my entire project to 2017.1 I noticed some odd things going on with audio.

I'm using footsteps as an example, but this happens with all other audio clips. Footsteps happen more often than the rest of my sounds so that's where I noticed it first. Each footstep SFX is a gameobject with an audio source that gets instantiated. Settings (volume, pitch, etc) does NOT change at all. However sometimes, one sfx will play louder than the rest. Inspecting the audio sources they all have the same values (volume), even after hearing one 'pop'.

See the video for an example. Example project attached, but since it happens so randomly the video might be more useful.

I could not reproduce this with in a non-beta version of unity, so I'm thinking something changed. I could not find anything relevant in the release notes

Any idea what might be causing this, and how I might be able to fix this?

Unity 2017.1.0b9. Windows 10

 

Absolutely! Submitted, case# 921686

 

I have not tested any Unity 2017 betas - just mentioning in passing... Anecdotally we've noticed this happening in all of Unity 5.x OSX, using both the sound api directly and various wrapper apis.

Most of the time I notice it on short interface sounds like button clicks/beeps (usually pcm or adpcm decompress on load and left in memory, not streamed or mp3/ogg) - every dozen button presses or so one would play loudly. I never made time to look at it more closely and have not filed any bugs about it. Longer sounds using the same import/usage settings never seem to suffer the same problem.

 

@greg-harding Thanks for the info! Seems like it's the same issue, or at least related.

I tried to reproduce this in Unity 5.5 on Windows 10, and had it playing 1 sound every 0.1s, and let it run for a good 10 minutes without hearing any 'popping' loudness. Could have just been lucky as the popping seems to be random, or maybe it's only an issue on OSX in previous versions of Unity, or maybe my test wasn't thorough enough! Good to know I'm not the only one who has experienced this though

 

It's always good to know that you're not going mad all by yourself If I get some time I'll do some tests with Unity betas.

 

Got an update from the Unity QA team

 

Nice. I wonder if it's related to the sound clips being small or using a particular import setting...

 

This was actually one of my thoughts. I tried adding (5 seconds of) silence to the end of my short footsteps sounds I was testing with, and the longer sounds still had the same issue!

 

Sorry for me being lazy then. I kept putting off making a repro and filing this old bug

 

Might even get a tshirt out of it for your trouble, who knows!