Macbook Pro Sound Not Working Through Headphones

Wondering if anyone can help me with this one.

I was listening to music on my Macbook Pro through my headphones when the sound suddenly went all muffled. It almost sounds like the sound is playing under water...

Anyway, I checked my headphones on other devices to make sure they weren't the problem. They weren't, so here I am 😢

I played around with the Sound in System Preferences and the only thing that seems to solve the issue is by adjusting the sound fully left or fully right. This makes it play through both headphones but still isn't the same quality as before...

Surely there must be another solution to this, right?

I hope this makes sense. I also hope I'm just being an idiot and missing an obvious fix.

Thanks in advance 🙂