It should extend about 2" larger than your speaker, on all sides. I would suggest that you try at least 3" thick 4 is better. Now for the best coupling, attach the marble to bottom of your speaker. Have your supplier drill 3 holes about 5/8" diameter in a triangle pattern that will be covered by your speaker. Don't forget to have them counter sunk so the heads of the bolts won't be exposed. Use these for a pattern to drill holes through the bottom of your speakers. Now use a 1/2" bolt, preferably fine thread through the marble & the bottom of your speaker. The speaker will then be totally coupled with the marble, with the maximum effect. The effects of the bolting together will be noticed by rock solid bass, better focus, added detail. Simple as this is, it really works. I have my Duntech Sovereigns bolted to a 4" slab of marble, polished black to match the finish on the speaker. The results are outstanding. Good Luck! |
Ditto to what Audio4fun stated on the benefits of marble, though I have heard dimensions of 4" additional on all sides to the dimensions of the speaker bases (i.e. 8" total greater dimension on all sides).
However, Duntech Sovereign speakers are about approximately 75" tall, 18" wide and 23" deep and weigh approximately 170 lbs apiece (I may be off a bit on these dimensions). Duntech Black Knight speakers for awhile came stock with a very heavy, dense base bolted to the main speaker similar to Audio4fun's stated method for his Sovereign.
Practically speaking, most speakers will have to settle for resting their spikes on a simple marble bass platform with the 2" larger dimensions stated by Audio4fun.
Also, I have been looking for marble for my current speakers and am finding it difficult to find a thickness in excess of 3/4". If you do find a source of a thicker marble please let me know.
By the way, expect to pay a premium for marble (or even granite). I am being quoted approximately $500 for two 25" x 20" x 3/4" slabs of polished Black China marble. |
The best marble under speakers is the cheapest marble - ie. the marble with the most impurity. The impurity stops the marble ringing. Is is dolomite that is the impurity? I cannot recall - but I have tried different marble and the sound is better with the cheaper stuff. |
Where do you guys get this marble? Just 3 days ago I put some ceramic tile 1/4"X 12"X 18" under my speakers.It was very cheap ($2ea.) and it was all I could find that would fit.I have my speakers spikes almost all the way into the speakers.They are out about 1/4" I hear no ringing or anything else other than deeper and tighter bass.I still would like to try some marble if I can find it. |
david: most cities of any size have suppliers and fabricators of stone countertops, floors, etc. i have purchased over the years several "scrap" pieces of marble and granite from a supplier in denver. i've not used these under speakers, but i know from experience that pieces of marble of the "correct" size for most speakers' footprints are readily available. the prices will vary rather dramatically depending on the color and "purity" of the marble you want. as redkewi sez, tho, you shouldn't go for the purest stuff, e.g., white carrera. your choice of stone, and its relative purity, will likely be dictated by the color you want. the last piece of marble i bought was "green empress," which i used as a top insert on a muse model 18 sub; it was beautiful but i wouldn't choose it to mate with my current speakers. good hunting. -kelly |
If I do bolt the speakers to the marble, am I doing away with spikes all togather hence adding mobility by sliding? |
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.
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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! |
My speakers are AR 302's. They measure 24X12X12. I needed 8 to 10 inches of height. Stands would not do, as I have 5 cats and the cats tend to lean against the speakers and topple them. So, I did the following: I built stands using frosted glass blocks ... I used 6 blocks per each side (12 in total) ... they measure 8X8X4 ... so I built 2 rows of 3 blocks (end result ... each row is 8 x 12 ... together they measure 16 X 12 X 8 ... W X D X H) I used a silicone adhesive to hold each row together. On top of each stand, I placed a single 12 X 12 X 1/2 marble tile. Each glass block stand weighs 42 or so pounds. Cost: 12 glass blocks go for $60; marble tiles go for $10. Very effectively disengages the speakers from the floor ... very stable (have them on hardwood floors)... |
Refer to my post on audioreview.com/message/dcfourmid6/6975.html concerning stone platforms for floor-standers. MikE
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Regarding purchasing your piece of marble. My wife suggested going to a cooking or kitchenware store. They supply marble for pastry rolling and it's very inexpensive. You can then cut to size with a tile cutter. Just a thought to save you money. |
How would this slab of marble do for monitors? Any one have experience with it? |
Kevint: Do you mean placing the marble between the floor and the stands? I have found a general belief in the forums that stands need to match the type of floor that they are used on. Heavy massive stands for floors that have very little give (such as slab floors) and rigid but lighter stands for floors that have more spring or give to them. I have used both types of stands on a floor (heavy plaster cement type material) that has very little give to it and found the first type of stand to offer superior sound. I started off with light rigid stands and did try placing marble between the floor (resting on top of the carpet and rug) and the bottom spikes of the stands. This setup made the system sound thin and bright. I tried it out with two different amps (ss and tube) and two sets of speakers (Castle Isis and Renaud Twins). I did not try spiking the marble to the floor though. I also tried the marble between the top plate of the stand and the speaker with a substance similar to Blue Tack as coupling on both sides of the marble (I did not try spikes). This setup sounded better than the first go round, but not good to my ear. Now that I have heavy massive stands I may give both setups another try. I still wonder if spiking the marble to the floor would be an improvement, but just do not have the materials available to try it out, plus the spikes would have to be affixed to the marble for safety and stability issues. Also the marble that I used is only 1" thick and I beleive that it is called shystic (sp) marble which is not at all pure in its makeup. If you try any of the combinations out I will be interested in the results that you achieve. The marble that I used was given to my wife's girlfriend for her patio. I have another 4' piece of the marble, but need to have it cut to size (we just want a pastry board cut from it and the remaining portion will be enough to try on the new stands and speakers). If it doesn't work I will just place my wife's orchids on the pieces. I doubt if I will get around to it anytime soon though. |
Kevint, I have monitors and carpet and was having trouble levelling them so I bought 2 13"x13" floor tiles. I would be worried about raising your monitors too much because of the vertical position vis-a-vis your ears. I found that the sound is tighter and toeing in or out is easy. I also placed 10lb weights on the top of the monitors to kill some of the resonances. Cheers. |
I had a problem in my den system with my Alon V loudspeakers. I was losing all sorts of bass between about 50-70 cycles. This gave a very "un-dynamic" (if there is such a word) presentation, and also offered the impression that the upper bass was bosted. I tried everything to solve the problem. Room placement first, then acoustic treatments including ASC Tube Traps; nothing helped. My dealer finally suggested that the bass might be getting sucked out due to the flexing of the wood floors, and thought that I might try reinforcing the flooring to help offer a more stable platform for the speakers. This was nearly impossible without major renovation, as the den is on the 2nd floor of my home. So as an alternative, the dealer suggested that I try some heavy marble slabs under the speakers. As some of you have found, not only is it hard to locate, but marble can also be quite costly to have custom cut. Now, I don't mind the expense, but only if the results justify the cost. so here is what I tried FIRST. I went to my local Home Depot and purchased to CONCRETE slabs from their outdoor garden department. The slabs measure 18" x 18" x 2" and come a few colors too! Best of all, they were only about 4 buck each! I luged them home, set them up, and viola! My MIA midbass was much improved! The midbass suckout went from being about 7db down to about 2 db down, but best of all, in actual listening, I noticed NO problem in the midbass after intalling the concrete slabs. I actualy wound up painting the slabs black and just keeping them. They might not be elegant, but for less than 10 bucks they get the job done. The only other advice I might ad is to carefully examine the slabs before you purchase them to make sure the surfaces are flat; there is great variety in the quality control of these garden products, and if the surface is not perfectly flat, the slab might not lay perfectly flat on your flooring. Oh yeah, I also covered the bottom of the slabs with felt to help protect my hardwood floors. Sorry to ramble, but I hope this helps. Regards. Robert. |
Due to two little ones, my monitors are sitting alone on top of a massive oak chest made of one inch slabs of oak. Monitors are at the right height and out of traffic (stands would get knocked over at some point) but they are obviously a bit too close to the wall. So, I want to tweak them as they are very detailed under the right conditions. Appreciating all the suggestions. |
Kevint: spike the monitors on the slabs? |
