Broken laptop speakers?

So I bought an Acer quite awhile ago. It works great but I was using it one day and noticed the one of the screws had just fell out the bottom, a couple of days later another one did the same. I didn't have a screwdriver small enough at the time so there wasn't much I could do but I have now tightened them all up. However there seems to be a problem with my speakers. If something is played at high volume there seems to be a kind of rumbling. The problem is fixed when I grasp the laptop case close to the mouse pad. Is there something maybe loose inside the laptop that I might need to go in tighten or what? If anyone has any ideas what I can do to fix this or what the problem might be that would be great!

Thanks in advance!

You may want to find the source of vibration, or you may not, as deconstructing laptops can be very complicated and risky, as they're genrally not designed to be maintained at home. Of course, I cannot advise you whether or not you are prepared to dismantle it. Personally, I wouldn't care, because laptop speakers suck and I rarely choose to use them.