USB-C headphone adapter causing videos to speed up and no volume

Hello muse2me,

Welcome to Apple Support Communities!

We want to make sure your iPad mini is working as expected using the adapter.

First check for any pending iOS updates, which can help make sure the software is working as expected. This Apple Support page can help get those updates installed: Update your iPhone, iPad, or iPod touch - Apple Support

"Update your iPhone or iPad wirelessly

1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.
5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do."

If the issue continues, try a normal restart and then test again. Does it only happen in the one app? Which app exactly does it happen with? Are you able to test using another adapter and pair of headphones?

We hope this helps to further isolate and resolve the sound issue.

Cheers!