AR90 and speaker spikes

[rrcrain]

I’ve kicked around the idea of putting spikes on my AR90s for some time; half out of the desire to prove to the local shop they didn’t really do anything and half out of the hope they would. The room they sit in has deep pile carpeting with a thick padding below it, and this sitting on cement. (Walk out basement). Excessive bass tends to be a problem in this room and the sonic signature is quite often “swamped” by the bass.

I tapped the bass plate and installed the threaded inserts and the local audiophile shop loaned me a set of spikes. Nothing outrageous, just plain stainless steel spikes. If they didn’t work, I return them and owe them nothing.

Two weeks later, I was convinced I wasn’t hearing any difference and asked a musician to listen to them with me. Once he was familiar with the sound of the speakers with the spikes installed, I removed them and played the same tracks a second time. We were both taken back by the change. The feet did not add anything, but rather subtracted a great deal of excessive bass from the sound stage. This had the effect of making the speakers sound brighter simply by controlling the bass. The bass was tighter and much more defined at the same time. Given the mass of the cabinets, I’m at a loss to explain the change in sound.

Any ideas of the physics involved here?