Getting granite tomorrow.


Making an isolation platform for my Acoustic Signiture TT. It is 18x24. I have this materials. Granite slab 1 1/4 thick. 2 MDF boards 3/4 thick each, Cork one inch and 2 rubber truck liners 3/4 inch thick and 8 wooden buttons for support. I was going to put MDF boards on bottom then rubber then cork and last granite on top. Is this the best order? Or should I make 2 sandwiches out of materials? Also If I dont use spike cups for TT will I crack the granite or damage the spikes? I though it may make a better isolation or do you think it would matter. Any opinions appreciated
128x128blueranger
Agree with Doug about speakers. I put one expandable column directly under each speaker in the basement below my listening room. I bought these at Home Depot for about $30 each. My speakers aren't spiked because I have very soft, very old wide pine floor boards in my listening room. The speakers are, however, on hard round cones and as each speaker weights 200 lbs, they don't move. As Doug says, one wants all of the speaker's energy directed at the forward/backward movement of the cone drivers. The cabinet should not move at all.

I also placed two columns under my equipment rack to support it's massive weight, but also to reduce the floor bounce. I've found the solution to be quite effective.

I'm in the process of building a new rack. I considered two distinct approaches. One is to have massive shelves to which the components are coupled, but the shelves need to be isolated from the rack structure and from floor born vibrations. The other approach is to have a very rigid, heavy rack coupled to a solid floor but have the components isolated from the shelves. I've chosen the latter approach and have the components on a Vibraplane and Townshend Seismic sinks for isolation all on a very rigid and massive rack/frame system. I guess I'll find out if it is effective once I finish building it.
Here's my added thoughts in relation to speakers and suspended wood floors;

I have a suspended wood floor "joist below are resilent" , two layers of 3/4 inch ply on top. First sheet is tongue and groove with glue applied on the top portion of the joist and t/g and then screwed. Second layer, 3/4 inch stangered offer the first sheets joints. Glue spead using a notch trowel of entire area and then sheet installed. Screwed threw to the joist and everywhere else screwed every 6 to 8 inches. Finished with underpad and carpet.

With speakers in place "MBL 101E's" the floor still interacts "this sucks big time" floor interacting as a trampoline and for sure effecting in a negative way the sonics.

I have tried so many variations of this and that and never been really fully satisfied but always learning along the way.

My latest invention; 4 Large Herbie pucks with Titanium incerts, then placed a 3/8 inch ball bearing on each and then ontop of that a Symposium Plus Svelt platform. The carpet and underpad it pretty plush so the Herbie puck and ball bearing have pretty well sunk in leaving the Svelt platform bottom pretty well level with the carpet.

My speaker is placed upon with no spikes, very interesting indeed in a positive way. Next will be to use Rollerblocks instead of the Herbie puck and ball bearing but for now sounding very nice and with very minimal floor interaction.

Stand is iso;ated along with each pce of gear, my table is placed upon a Minus K. I have my motor with is also but will be changing that and only have the table it's self and compare.

It's all very interesting indeed, what I have learned is vibrations interacting are evil in a negative way.
Thanks for the responses all. Doug, indeed my experiments have proved that anything that allows the speaker to move in any plane results in exactly what you and Paul are hearing. Thus far, I've found that rigid spikes allow for the best sound in my application. The Track Audio spikes intrigue me as they are offered in both a coupling and decoupling version; from my reading it seems the decoupling version can be adjusted for various mass loads, and that the degree of compliance is minimal - still as you rightly point out, anything that allows the cabinet as opposed to the air to move is theoretically detrimental. Alas, support from beneath isn't an option since the room is over the garage. Perhaps I should be focusing on better coupling between the speaker cabinet, the spike and the floor. Back to the drawing board.
Adding to my info. above I believe it will depend on the design of your actual speaker for end results, not all being equal.
I set up my TT stand in way descibed by Audiogalore and it works for me. 24X18 X 1 1/4 granite, 1 inch of cork, 1 1/2 inch rubber, 2 pieces 3/4 thick of MDF with sorbethane pucks. Bass deep and tight. No glare from highs. Also of note I turned up the gain from 42 to 52 on phono preamp and ran Adcom preamp in passive. That was a big difference too on the Shure 97xe. Having an SAS stylist come in next week. The Benz L2 was no slouch and conveyed more musical detail but the Shure tracks better and is a very very musical cartridge. The Benz was humming more and more and finally I had enough. Couldnt afford to get a 1K cartridge so I got the Shure for the time being. Some other members wrote they had negative experiences with granite. Maybe it just didnt blend in with their systems or maybe they didnt use enough dampening. Mike