I'm having the same issue. My surface 2 is only 3 days old.
Bought it on Friday, then on Sunday, there was an update done. Before that update, I don't recall the sound being bad or anything. After that update, Everything went downhill.
- Left speaker is about 50% of the volume of the right speaker.
- Volume in general is very very low and it seems to get lower by the day.
- crackling/poor sound coming out of speakers.
I'm having this no matter what kind of app is producing the sounds (XBox music, Youtube.com... even the system sounds).
This morning I tried a refresh... issue still there.
Before leaving for work, I launched a full restore. I hope this solves it .. we'll see tonight.
If not, i'll have to return it to the retail store.
It really seems to be a software/driver issue since it was fine at first and not after the update but the sound comming out of the headphones jack is fine so i'm confused.
I love my Surface 2, but this is like a grey cloud over my party !