I just finished my first sonosub and hooked it up to my old plate amp last night. At first I thought it sounded great, but then I noticed a vibrating distorted noise coming from the driver. When I touch the dust cap or rubber surround it stops, but as soon as i let go it starts again. Do you think there is something wrong with the driver or could i have something inside the sub that is touching the driver? Or could the amp be doing this? I am new to this so any help would be appreciated.