The distortion seems like a common problem, specifically in the left speaker. I also created a thread about it: Rattling / Buzzing in left speaker
There are a few things you can try if you google around (like re-seating the speaker). What I went with was putting some folded up cloth between the speaker and the palm rest. This allows me to crank the audio a bit higher with minimal distortion. It’s still not great though, and it’s no my list to open it back up and try foam instead of cloth.