Hey there Tristan_E,
Thanks for reaching out to Apple Support Communities. We're happy to provide some assistance.
Does this occur when using headphones? If so, the actions in this article may help:
If the sound from your wireless headphones cuts out or is distorted - Apple Support
If not, does this occur in all areas or specific areas? This may help us isolate the issue.
Let's make sure your device is up-to-date. If it is updated, let's restart your device. Restarting your device and making sure it is updated can resolve many unexpected issues.
Take a look here on how to restart your iPhone: Restart your iPhone
Take a look here on how you can update your iPhone: Update your iPhone or iPad
Keep us posted.
Have a great day!