Arvin - floor coupling is, in my experience, a worthwhile endeavor. During development of the 03 In the late 70s, we discovered a new problem attributable to phase/time coherence, of a bothersome upper midrange jitteriness. A cure was to couple the speakers to the wood floor via 3 pins. That solution became part of the product and rubbed off into the general 3rd party stabilizer feet solution. Piercing carpet via spikes also firmed up the bass. However, coupling directly to concrete sometimes produced an undesirable edginess. In my time at Thiel, we supplied invertible pins where the domed end could be used to concentrate the load, significantly smush the carpet, but not penetrate to the underlying floor. A similar effect could be gotten by placing the spikes into small diameter cups of some kind. In the day I had some cups machined from brass (for shows). The top had a pointed-bottom hole to match the pin, and the bottom was a hemisphere about 1/4" diameter. You can buy online brass hemispheres and drill a dimple to capture the point of the pin.
