Does anyone know whether you can put spikes on a Velodyne HGS-15. My previous M&K subwoofer had threaded holes for spikes. I don't see any equivalent on the Velodyne. There are some feet which appear to have some type of plastic cap which I assume allows them to slide on wood or something. Maybe these pull off, but I didn't want to start trying to pry things off my new sub unless I knew they were supposed to come off. Maybe this subwoofer just doesn't support spikes.