Best treatment for speaker feet????

The underlying principle here is that the speaker (enclosure/frame) must be "mass coupled" to the floor (or, preferrably, to the planet!) so that the only thing that can move is/are the drivers. Spikes are simply the easiest and least destructive solution in most cases. But you could, for instance, bolt your speakers right to the floor;--)

And then of course, there's the issue of floor itself: it mustn't move at all. This is often a problem with wood framed (joisted) floors where the subfloor can deform (bend) slightly as it spans between joists. However, there are some tricks (which are obvious to architects and builders) that will minimize the effect of this common type of floor deformation:
1.) The best situation is if the speakers point (front to back) along the same direction as the floor joists. This is most likely to happen automatically if the speakers are placed on the long wall, since joists are usually oriented to span the short dimension of the room. Why is this (long wall) placement best? Because the subfloor's movement (if any) only allows the speaker to rock from side-to-side in this case. But the drivers only move forward/backward, but the direction of the floor joists in this case, prevents the speakers from reacting (rocking) front-to-back; it they did/could, it would rob the drivers of energy they could/should be transferring to the air! This condition would also reduce the drivers' transient response (accuracy in following the signal) -- a problem that particularly degrades the midrange. Of course, they can STILL (possibly) rock from side to side, but that WON'T MATTER unless your speakers have side-firing woofers ;--) Of course there are other acoustic benefits to 'long-wall' placement.
2.) So if you are lucky, and able to orient your speakers in line with the direction of the floor joists as described above, you'll do even better to 'center' the speaker (left-to-right) over the space BETWEEN two joists, as opposed to it straddling a single joist. This will mostly eliminate side-to-side rocking -- although this is less critcal as I explained above.

Implementing these "tricks", if you can, will result in a huge improvement in transient response; e.g. detail and clarity of vocals, plus cleaner (more slam) in the bass response. And it's free ;--)

3.) Unfortunately for many of us, there are multiple reasons we're unable to place our speakers along the long wall, as in 1.) and 2.), however, it's still possible to realize many of the same benefits (minimizing forward/backward rocking) if you will crawl under the floor and actually locate the two joists (now running side to side across the room) which are nearest the speaker -- the one closest in front of the desired speaker location, and the one running closest behind, and mark their location on the floor above. Then center the speaker(s) front to back BETWEEN those two joists -- again, as opposed to the speaker straddling across just one joist. This "trick" will further minimize forward/backward rocking -- the taller/heavier the speaker, the greater the benefit; although, even with monitors on stands, it still really helps to increase the speakers' effective mass by filling those stands with sand or shot. BTW, it's OK to add toe-in to the speakers, but wait until after you've determined the best location relative to the floor joists.
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Devilboy, spikes when placed under speakers, are for mass-coupling the speakers to the floor. Nothing more, nothing less. As I said, you could bolt the speakers to the floor and acheive the same thing, maybe better! The speaker designer engineered his speaker as if it would be operated in a COMPLETELY RESTRAINED state -- the specified performance of the drivers he used depend on it! If you say things sound better than with the spikes going through the carpet and into the floor, I would offer that the granite slab is now probably bridging across the joists underneath, whereas before, without the granite, and unbeknownst to you, the spikes just happened to be landing on one of those weak places in the floor, as I described in my post. I can't tell you how many times I've seen audiophiles fooled by not recognizing this oversight! (Same comment applies to Stereo5's experience.) You guys should go back and review exactly WHERE on your wood floors the spikes were originally landing, relative to the joists underneath -- and then reposition the speakers as I recommended! Then you can tell me about how great the granite works;--)

As for the comments about

vibrations travel down the cabinet, through the spikes, into the granite. Then, those vibrations bounce off of the granite, travel up through the spikes and back into the cabinet.

that is just patently impossible! The whole point of spikes and cones (especially when used under electronic components and turntables, etc.) is to act as MECHANICAL DIODES; meaning vibrations travel out the pointed tip, but CANNOT return back the other way! If the speaker cabinet is vibrating, either the designer meant it to, as in many of the English bookshelf speakers, or, more likely, the enclosure is inadequately braced! The only "vibrations" a speaker should produce are the ones from the drivers when coupling them to the air!

Further, you are certainly doing your speakers no justice by placing them on a "carpet sandwich"! I don't care if the granite slab weighs 500 lbs! It will still allow the speaker to rock. Even a few micrometer 'squish' at the speaker's base, will translate into a few millimeters of sway at the top of the enclosure (you know, where the tweeters are located?) and that is enough to cause doppler distortion in the high frequencies coming from those tweeters.

Go back and examine your floors and determine the location and direction of the joists. Then position your speakers as I indicated and I guarantee, you'll get better performance than you have so far -- that's for sure! All that speculative pseudo-science is the devil! -- only physics will set you free ;--)
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Bmckenney -- think about this: your speakers/drivers (unless you're talking about down-firing subwoofers) vibrate horizontally. Your floor vibrates vertically. So it's not your speakers that are exciting the floor. It's the air pressure (SPL) of the waves in the room (which are omnidirectional) that are exciting the floor, and there's not much you can do about that, other than stiffen the floor from below, or by adding another layer of subfloor.

Decouplers on speakers are always inappropriate anyway, because the object is to restrain the speaker enclosure from any kind of movment whatsoever. And anything resilient between the speaker and the floor (or slab) that allows the speaker to rock forward/backward in equal-but-opposite reaction to the movment of the driver(s) will degrade performance: bass slam and hi-freq. transient response. So the notion of decoupling a speaker from the floor is completely counterproductive in terms of getting the best performance, and any speaker manufacturer will tell you that! Some people might like the way their speakers sound when they decouple them (God knows why!?) but they are definitely NOT operating the way their designer intended,

So get your speakers back on their spikes, but pay some attention to positioning them (relative to the floor joists) as I outlined above.
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