My Velodyne HGS15 II starting making a continuous popping noise when it turned last night. Has worked perfectly up to that point. It started happening for no apparent reason. Sat down to listen music and the minute the sub turned on the popping started. The sub is less than 9 months old and under warranty so I have no problem taking it back if something is blown. However if there is anything I can do please let me know. I would rather not have to lug a 90lb. box in and out of my home again. Thanks in advance.