# Random Pitch on Async instrument Pop **URL:** \ **Category:** FMOD Studio\ **Tags:** unity\ **Created:** [September 23, 2020, 1:51pm UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215 "2020-09-23T13:51:35Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![thommazk](https://avatars.discourse-cdn.com/v4/letter/t/ba8739/32.png) [@thommazk](https://qa.fmod.com/u/thommazk)\ **Post date:** [September 23, 2020, 1:51pm UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/1 "2020-09-23T13:51:35Z")
Hello! I’m having an issue where whenever I put a random pitch variation on an async sound, FMOD /Unity plays its end with a ‘pop’. I already verified if it’s on zero-crossing. Could it be the compression setting or something? Thanks ---
**Author:** ![richard\_simms](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/richard_simms/32/261_2.png) [@richard\_simms](https://qa.fmod.com/u/richard_simms)\ **Post date:** [September 30, 2020, 12:07am UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/2 "2020-09-30T00:07:43Z")
Are you using a lossless format such as WAV for the audio? MP3s will add some silence at the beginning of the audio file that could cause issues with looping seamlessly. Also test with “Streaming” turned off if it is turned on. Are you able to upload the audio file in question to here for me to test? I am able to get looping async instruments with random pitches. ---
**Author:** ![thommazk](https://avatars.discourse-cdn.com/v4/letter/t/ba8739/32.png) [@thommazk](https://qa.fmod.com/u/thommazk)\ **Post date:** [October 1, 2020, 5:27pm UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/3 "2020-10-01T17:27:34Z")
Yes, I’m using a stereo WAV, 48khz file, and with STREAM option off. Looping isn’t quite the problem, sorry if I didn’t explain right. The sample is an OneShot situation, at the moment of player’s mouse click. Here’s the file: [https://filebin.net/z06bt5yrk4x927lr](https://filebin.net/z06bt5yrk4x927lr) ---
**Author:** ![richard\_simms](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/richard_simms/32/261_2.png) [@richard\_simms](https://qa.fmod.com/u/richard_simms)\ **Post date:** [October 5, 2020, 3:42am UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/4 "2020-10-05T03:42:43Z")
I’ve been testing using your file but couldn’t experience any pops. Could you provide a video or a profiler session of this happening? ---
**Author:** ![thommazk](https://avatars.discourse-cdn.com/v4/letter/t/ba8739/32.png) [@thommazk](https://qa.fmod.com/u/thommazk)\ **Post date:** [October 6, 2020, 11:27am UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/5 "2020-10-06T11:27:00Z")
Sure, here’s the link: [https://streamable.com/6dn4fn](https://streamable.com/6dn4fn) ---
**Author:** ![richard\_simms](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/richard_simms/32/261_2.png) [@richard\_simms](https://qa.fmod.com/u/richard_simms)\ **Post date:** [October 8, 2020, 12:00am UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/6 "2020-10-08T00:00:03Z")
I think I see the problem. If you zoom in really close to the beginning and end of the audio file there’s a small non-zero point in the waveform. This is what’s causing the pops. Add a small fade in/out to the audio file and it won’t pop anymore. ---
**Author:** ![thommazk](https://avatars.discourse-cdn.com/v4/letter/t/ba8739/32.png) [@thommazk](https://qa.fmod.com/u/thommazk)\ **Post date:** [October 8, 2020, 6:28pm UTC](https://qa.fmod.com/t/random-pitch-on-async-instrument-pop/16215/7 "2020-10-08T18:28:55Z")
That’s weird. I can’t find any non-zero point in the waveform at the end of the file I’ve shared here. However, fading in at the start of the file solved the problem. Thanks! I wonder why is this happening as it looks like the pop is at the end of the file? 🤔