Marble to place speakers on?

I agree with the above comments/suggestions. At a prior home where I had a pier/beam foundation, I used marble slabs (but did not bolt the speakers to them) that I found at a rock shop while traveling through Arkansas. The results were impressive (ditto previous comments). I am currently in a home with a slab foundation and have spikes that go through the carpet and pad straight to the foundation. The results a very similar. I still have the marble but it is being used for other applications (in the backyard). Bottom line: Use spikes if you have concrete under your speakers. If not, plan a vacation! :-)

Good thread. Thanks for visiting/revisiting this topic.

I'd been quite interested in placing marble slabs under my speakers, but found it difficult to source reasonably priced marble/granite, and was also warned-off by several Audiogon members.

Members concern in general was the ringing problem, as has been mentioned here (including how to avoid it). However I was surprised and concerned to hear one member stating that the whole notion of “mass loading/active damping” was “flawed” (although he didn’t put it that way). At the time, the member and I were discussing mass loading of any equipment – sources amps or speakers.

To quote the member directly "a heavy stand... would result from mass loading... will alter the structural Q of the floor to lower frequencies, akin to placing an anvil atop a trampoline." "Once energized (inevitable, beit by footfall or passing car), it will continue to drone much longer and with a great deal of power.” This suggestion made sense to me and really put me off of the marble thing. I actually started giving serious consideration to products like the Townshend Seismic sink/stands.

I’d like to know if anyone is attaching spikes/cones to the marble, then placing the speaker stand spikes/cones on top of the marble slab – ala Mana Acoustics turntable & equipment isolation stands.

I find this thread interesting.For a couple of years I have considered this as I have an old,crack infested wooden floor that makes spiking the speakers through the carpet/pad difficult.I never seem to be able to get them solidly spiked.My concern is the thickness of the marble and the subsequent raising of the tweeters way above ear level.The obvious remedy is to have the spikes out further in the back of the speakers.Please be kind to me in the follow up to this "obvious" remedy,but is this correct? Also,is this the best/only way?

Dave,

There is a marble and granite wholesaler in Lancaster. For granite, you will speed $50 a plate (custom cut). I won't worry so much about the added height unless your couch sags. I did talk to Audiopoints last week about using their Sistrum Platform on a granite slab with wood/carpet as flooring. They recommended against it because of resonance transfer back to the speaker. They did recommend installing 3/4" dia stainless steel or brass rods across the support beams with washers and nuts (2 - 4" beyond the speaker perimeter) to enhance structural integredity of your flooring and resonance conduction to ground. Email me if you need more info. For me, if you can buy 3 - 4 plates of marble at Home Depot and try spiking the speaker to the marble you would only be out ($2.50 x 8) and then you could experiment with the rods.

Sounds like we have a lot of interest here. It addition to my first post, may I suggest that there is no substitute for experimenting. As for sources, for thicker or larger pieces I found that monument works are great resources. Many times they have large stones that have been broken, & are willing to sell them at very reasonable prices. Cabinet installers that use granite or marble tops are a good source for the thinner pieces, ¾” or 1”. You may also check out tile supply houses. What I usually look for is damaged or broken pieces & them let the supplier cut them in sizes I can use. These stones can be used to fine-tune most systems.
I have found that if I use larger pieces with components sitting on top of them that the spiked feet work very well between the component & the stone. Again experiment with what sounds best; there is definitely a difference in each method. For speakers, bolting the slab to the bottom couples the stone to the speaker, virtually making the stone a part of the enclosure. If the stone is not attached I would suggest trying feet between the speaker & the stone with a large piece of stone resting on top of the speaker. This adds to the coupling affect. Yes, by attaching the stone to the speaker you eliminate the need for spikes on the bottom of the stone, making it much easier to move or adjust your speakers.
I have also had great success using a partially inflated 12” inner tube under the stone for components other than speakers. Here again, experiment. I have found the affects of using stone & inner tubes to make great differences in what we hear & at a very reasonable cost. GOOD LUCK! & HAVE FUN!