The SubDude HD from Auralex is a platform wrapped in cleanable black velour, and designed to prevent the vibration of a subwoofer's enclosure from being transmitted to the floor, or any other surrounding surfaces. Subwoofers create large, low frequency vibrations. When coupled directly to the floor, it causes the floor and the objects to resonate - not only at the fundamental pitch, but also at other harmonic frequencies, causing interference with the source. By eliminating upper harmonic resonances the listener is able to hear a truer bass tone below 100Hz. This translates to the listener as more accuracy in the low end, and a cleaner (less muddy) crossover between the sub and the full range LCR channels.