I have the same laptop and had the same issue. In case you didn't already figure it out, here's the fix...
1. Right click on bottom right speaker icon
2. Click on the little speaker above the sound bar
3. Click on advanced
4. Select a higher 24 bit mode
5. Click apply/ok
Problem solved. The sound quality isn't great on this laptop even when it's finally loud enough to hear clearly, but at least you'll be able to hear your media comfortably. Hope the delayed response helps everyone having the same issue. Otherwise, I got this laptop for under $300 about 6 months ago from Walmart, and for a bargain basement computer it works fine and handles video streaming and mp3's great. Good luck! Jim