Another test with music: https://www.youtube.com/watch?v=Ccrry7QROKs
This test video is here to help you with audio cable problems. Test your computer speakers for PC or MAC, laptops and notebooks, iPhones and smartphones, Smart TVs, headphones, headsets, earbuds and adapters as well.

When you see LEFT on the screen, you should hear sound on the LEFT speaker only. When you see RIGHT on the screen, you should hear sound on the RIGHT speaker only. If you hear "Right channel" from the right speaker, then it works correctly. If you hear "Right channel" from the left speaker, then your L&R cables are swapped by accident.

You have a mono sound system or a short circuit if you can hear "Left channel" and/or "Right channel" on both speakers.

This simple test should allow you to confirm that your sound system is wired correctly. This may seem unimportant but if you start hearing shots from the wrong side while playing a first-person shooter game or a character in a movie shouting from the left when they appear on the right in the film, it will become annoying and confusing!

Use full-screen mode to use this video more effectively. Take your time when fixing the system and fiddle with your cables and connectors.

If only a certain audio file shows the issue of having swapped channels, you can fix this easily: https://youtu.be/Ngmmhjxrdlk

Clouds were recorded with a Sony HDR PJ620.

I hope this is useful, please like and leave a comment if it is!