is there anyway to get that humm wen you use a softrack

i dont know if its even normal, im a new surfer, and when my softrack is on,,,my god. if i go past 30 theres a loud buz,like the kinda when you tape a baseball card on ur bike to make it sound like a motorcycle...is there anyway to get rid of this, or do i have to just turn up my stereo more?