changing volume w/ antialiasing on
 

when ever i change my sound volume by turning the dial on my keyboard, in all 3 of my quake3 engine games(sof2, rtcw, wolf:ET), my screen flashes to black and then back to as it was. its like it changes to a whole different resolution and then back just to make the sound volume different. is there any way i can keep on antialiasing and be able to change volume without my screen flashing?

im not sure which of my hardware is causing this:
geforce4 ti4600
soundblaster audigy2 platinum
HP usb multimedia keyboard
(all drivers are up-to-date)

this only happens to games powered by quake3