I gave out my laptop to a friend and he's returned it with a poor sound quality. He said he noticed the problem after connecting it to a speaker and within an hour of playing music, the sound was distorted.
What might have happened in this instance and how can troubleshoot it?
The first thing I thought of was the volume that he used. Speakers in general will do this when the volume is at max capacity over long periods of time.
I had the same problem with my laptop a few months ago. The speakers were making a scratchy sound when I turned the volume past 50%. It went away after I updated the sound card driver. I don't know if this will help you.
I agree that updating the sound card driver may help. As a short time measure, you can reduce the volume level which sort of mutes the troublesome speaker. I do not know how to exactly describe this but it normally involves clicking on the speaker icon then clicking on the 'sound' option.