Random tri-tone sounds since updating to iOS 11

I've had this problem for several years and it was driving me absolutely insane. I would get the random tri-tone sound at different times throughout the day despite the fact that there was no notification on screen. I think I finally found a way to fix it and it was easy!

First, I would recommend closing all open apps. Then do a "soft reboot" by following the steps below:

Performing a soft reset is pretty simple

1. Just press and hold both the Sleep/Wake and Home buttons simultaneously for at least 10 seconds, until you see the Apple logo. You can let go of both buttons after the Apple logo appears.
2. Your phone will go through the usual process of starting up.
3. You’ll be back in your home screen.

After this, I never got another randome tri-tone sound. If it does happen, just do another soft reboot. Just had to share since nothing I tried ever fixed it. GL!

When I reset my 6 plus I had an issue with the game center app sending noises. have you checked all your notification preferences to see if some of them changed?

I’ve tried that procedure twice. It seemed like it made it happen less frequently, but it’s still there. I was even working with my phone while it happened.