Predator G9-793 Speaker buzzing when computer takes on heavy load (HELP)

[Opal407]

I've had this laptop for about 2 years now and it still runs great. The past few months though whenever I try to run any game that takes more than Terraria-level power, one of my speakers (left one according to sitting in front of the laptop) will steadily start to buzz louder and louder and becomes loud enough to hear over in-game audio through a closed back headset. When closing the program that was causing all the power consumption, the buzzing will steadily decrease until all that's left is the noise from the fans (that I have on a scaling slider for speed). My question then is...why the buzzing? Short of disconnecting the speaker, which I'd really rather not do, is there anything that can be done to fix it?

 

Any help at all would be nice as I'm looking to sell the old gal since I've recently come into some inheritance and bought a much nicer rig. Other than the buzzing from the one speaker, it runs amazingly and has no issues running even modern titles.