Occasionally very heavily distorted alarm sound or ringtone

[Ntei]

I am so happy it's not my phone but as it seems it is a software? problem judging by number of people and devices having this.

 

[Jonathanmr7]

Same here with mom 640 and a friend :B

 

[LightenSkies]

It's a common problem with both issues my insider program Lumia 640 does it to. Even on the fast ring.

 

[IamWinFan2]

Closing the app and restarting it seems to fix the issue. My guess is that its driver loading issue. I had similar problems with Windows 95 for a loooonnngggg time and upgrading the driver fixed it. Sorry about going so back in time.

 

[Diamond67]

Distortion fx lives strong even with Creators Update. Strange feature.

 

[LumiaGuy]

My 640 has been doing it since new with 8.1 and has continued since updating to 10. I guess MS doesn't really GAS about the issue.