A studio monitor, subwoofer, or guitar, bass, or PA cabinet, or stage monitor doesn’t operate in a vacuum, it interacts with the room around it. A big part of that interaction results from the surface that the speaker cabinet sits on – the floor, a mixing console, a desk, the edge of the stage. In a phenomenon called “coupling” the vibrations from the cabinet transmit into the surface, and are transmitted back again, resulting in a variety of interferences, not to mention phase and cancellation problems from the passive (coupled) device radiating energy into the air as well. All of this, naturally, changes the tone you or your microphones hear from the speaker.
For this reason, it’s recommended that you “decouple” the speaker cabinet from whatever it’s sitting on. Put your studio monitors on isolated stands or use Auralex MoPads Monitor Isolation Pads. Position guitar and bass amps, PA cabinets, subwoofers, and stage monitors on non-resonant isolators such as Auralex’s GRAMMA – Gig and Recording, Amp and Monitor, Modulation Attenuator. For larger cabinets, try the Auralex Great GRAMMA.)
You’ll be amazed at how much more clearer your tone becomes when you isolate it from the room around it. In fact, the amp or cabinet may even seem louder, as the increased clarity helps the sound project and cut through.