Need help with sound system

Hi all,

I use the Shazam app google extension to detect music from videos etc. I recently found that it wasn't detecting my music. I currently use "Speaker (Realtek High Definition Audio" as my other sound system "Realtek Digital Output" doesn't give me any sound.

However, what I discovered was as soon as I switched to the "Realtek Digital Output", Shazam started to detect songs again, even though I can't hear them play.

My question is, why does this happen and how can I fix it? Should I be using Realtek Digital Output instead, and if so, why isn't it giving me any sound?

Happy to answer more questions in the comments.