Where do you live? Under the El? How much rumble can there be?
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I have a similar setup with a 1" granite base. I used a 1" MDF board and sandwiched a 1/4" cork it has isolated all floor noise to zero and ever getting back to my turntable. MDF is allot cheaper and more effective.
Go down to your local home depot and pay $1.00 for a scrape piece. They will even cut it to size.
I have had good results using different types of isolation materials in combination. In my system, I use various combinations of maple, carbon fiber, sand, and viscoelastic materials, sometimes combining as many as three different materials under the same component. I have found that combining materials offers a significant improvement over each material used individually. I have not, however, experimented with granite, so I cannot comment on the likely results of combining it with maple. But I think your experiment is worthwhile. Good luck.
try just the maple and place Vibrapods, one at each corner, as footers. VPods are rated by weight loading; add the total and divide by four, then size appropriately.
Or try the granite with cones below the maple / atop the stone. Vibrapods under the granite atop the rack shelf.
A sheet of pink bubble wrap is another good iso material. The pink is antistatic and heavy duty so air will not leak out.
It appears what you are actually doing is coupling the materials, rather then isolating them. Try the vibrapod suggestion, very inexpensive. However, if you need the ultimate solution, best to get base like they put electron microscopes on. They can be had in the used market for about $20K. I know of a guy who did the latter for his $200K table.
I went the granite route under my table as well, and then discovered what a mistake it was. Granite rings at fairly high frequencies so you can hear the smearing that results. But it looks wonderful, Dakota Mahogany granite.
I also tried a hard maple shelf before the granite, which was also a mistake with my table. The wood tended to soften attacks so the wood smears in another way.
Best solution I have found so far for my stand and table is to use Stillpoints between the granite and table plinth. The vibrapods would probably work also, but I would suggest listening for any softening in the bass and in attack. I'm not really sure how much they allow movement since I have not used them. I do hear slight loss of bass slam with the Stillpoints, but I can live with that until I find a better solution.
Best of luck. Don't get discouraged, you may have to try several things until you find something that works well for your equipment and tastes.
I live in Manhattan so I have the benifit of living in a very largehigh rse building 27floors. I live on the 11th and while pondering the best solution to TT isolation. I was in my lobby while waiting for an elevator the Otis repair were working on an out of order elevator. I then reasoned that the shocks at the bottom of the pit were very large industrial springs and according to Otis weighing in at over 1200lbs per spring. Well I can tell you my audiophile juices really perked up and after precurring a pass key to the bottom shaft door. That night I was salivating with the thought that I have finally found the ultimate tweak. So sneakerly I took my TT down and very gingerly placed it on all 4 springs using a large piece of wood in the basement. I centered it and now the larger problem running a long phono cable up to my adcom 565 pre. Well being an audiophile this would never stop me or any. So of course with fleet of foot next day while the TT lay dorment on all 4 springs I ran to my nearest RAT Shack and bought 2400' of copper cable and yes done at last the best isolation system for a TT for next to nothing unless you count the extra long phono cable but I am an audiophile and must do all to get the best out of the system. You are all wondering how it all sounded this new found mass of isolation at the bottom of my buildings elevator shaft. I cued up an lp and with fast of foot ran up 11 floors to just make half the lp and it was a miracle. The soundstage and images were just the best "JAW DROPPING". But everything is not all pretzel's and beer. I had to time the end of each lp and dash out the door and run down 11 flights of stairs open the elevator shaft doors and lift the tonearm flip the lp and start all over again.I reason that this tweak will not only make every TT sound its best but keep all who try it in the best shape of their life.I thank you all and recommend this to all who live in a high-rise building with access to their elevator shaftway.
No, unless you have some visco-elastic feet or springs under your turntable, what you are actually doing is coupling (*not* isolating) your turntable to these materials. And every time you add another platform, you are introducing additional natural frequencies, since every material "rings" the loudest at a different frequency.
Schipo what you saw is not a spring at the bottom of the elevator shaft. In hi rise buildings we use whats called an oil buffer its a strainer using oil to cushion the cab when all else fails. In 2 and 3 story buildings you would see large coil springs in the pit. This should tell you that like in some designs oil is used with the build of certain turntable manufacturers. I have to give you the way to go award for your passion to get the best sounding vinyl front end. If you dont get up from that chair and try ideas you will never know what could have been better of worse for your system.
I ended up getting a 3 inch thick maple platform. Wow, I am very happy. Very natural. The best my records have ever sounded. I have vibrapod isolators under the maple platform. i could not be happier. I am suprised at how much better the table tracks records now. Its amazing how much their is to learn in this hobby.
I have had granite under my CDP, Amp and TT for a few years now. After reading this thread, it gave me pause. I grabbed my wife's bamboo cutting board and placed it under my CDP (on top of the granite) just to see if it would make any difference. It blew me away! The music was better, bass more defined and no fatigue- especially when the music gets really busy. I ran to the store and bought 3 more bamboo cutting boards. I put one under the TT and on top of the granite. The soundstage became spacey, less defined. So I tried putting the board under the granite and that sounded better. I put a board under my preamp, which is not on granite but has Sorbathane feet and got an incremental improvement. My amp sits on granite. When I put a board under my amp the improvement was dramatic. The bass became deeper and even more defined. No more fatigue even with the busiest music. So overall, seperating the CDP and amp from the granite with wood was a big improvement. The TT likes being on Granite. And I am smiling at the big improvement I made in my system for just a few $$ just by reading this thread.
Regards, Tonywinsc: I too am a believer in laminated bamboo for isolation purposes. For custom applications, most cabinet shops can supply 3/4" material cut to your dimensions.
An 18 x 22 x 3" bamboo (open bottom) "box" of 3/4" laminated bamboo was lined with 1/4" builder's closed cell styrofoam insulation and stapled in place, joins were taped to prevent leakage. 2" decking screws were run 1/2" into the underside every 3", leaving a length exposed to anchor concrete (large aggregate removed) poured into the platform's cavity. A triangular bracket was fixed inside to each corner. Outside shoulders then rounded with a router and after sanding, a coat of oil finish applied to the outside before placing the concrete. The brackets provide a surface for mounting feet. 2" felt discs are used there now but might be replaced with spikes, cones, sorbo. pods, pucks etc. later on. Materials used were those currently at hand. Distortion from mechanically sourced vibration is effectively addressed. As no elevator shafts are available, I will remain pleased with the results.
It could be that my catridge and arm work better with the wood.. The instruments just sound more natural and I get less inner groove vibration with the thick maple. One thing I may do is Lower my table so I get more soundstage. The maple is very dense and is in the wrong place as far as at my ear level. Once I move it lower I think I will be very very happy. The wood isolates better for me than the granite. I do understand what you are saying by the turntable liking the granite. The wood and granite both have their own sonic signature. I have gone back and forth but so far the maple is winning.
Believe it or not, I just bought a sheet of MDF from Home Depot. They cut it to size and it is actually the best so far. Better than the maple or granite. I have it under 4 Vibrapod isolators. 5 bucks. In fact, it is by far the best. I put the Maple wood under my isolation transformer. The Granite has not worked for me so far and the most expensive as well.
Tzh21y, this all suggests how different things work in some systems and not in others. I can only stand Vibrapods under things that have nothing to do with music. I tried MapleShade maple board and their special feet also, but returned them immediately.
I have many polished pieces of granite for free to anyone coming by to pick them up. I will not ship unless you pay me a $1000 each to pack them. :)
Tbg, the 1" granite is the shelf on my sandbox and is cut 1/2" smaller than the width and length of the inner sides of the sandbox. There is about 2 1/2 inches of sand under the granite. The ringing can be heard as smearing of detail in the lower midrange. I use the Stillpoints to decouple the table from the granite. It works quite well and also helps provide a very low noise floor. There is a slight softening of bass impact, but that is a trade-off I can live with. I wouldn't say that this will work for all components, but it has worked with my Gavia and stand. The granite is beautiful Dakota Mahogany so that is why it is still there. ;-)
Haven't tried on top of anything, but I have realized the benefit of having weight on some things. Like my speed controller, of all things. :-)
One approach that Thom Makris keeps mentioning is to attach some angle to the bottom of the granite with JB Weld and let the angle embed into the sand. Perhaps more work at getting the vibs down into the sand will make the granite work without the Stillpoints. Something to try this spring.
I just got a new turntable which did not fit into my old cabinet so I set about building a new one and again the perennial question of what to make the support shelf out of? I thought about granite but it has its own frequency response so I wanted to find something more neutral. I asked around and was told ebony was as acoustically neutral as anything and plexiglass was equally as neutral.
This got me thinking as after we had had an outside deck built the contractor had left behind a supply of ipe or Brazillian cherry.This is a very dense wood not as dense as ebony but almost. (You can't get ebony anyway) So I made a frame out of 4 1/2" x 4 1/2" legs and 1 1/2"cross pieces. I laminated about 9 pieces of 3"x 2"to make the platform then made another platform of 3/4" thick ipe and betwen two levels each of rubber and cork alternately to make a platform 3 1/2" thick. I suspended this platform on four cushions of 1 1/2" x 1 1/2" cork 1/4" rubber and cork sandwiches. I also suspended the whole cabinet on larger versions of my cork/rubber sandwiches
This was great for a while and sounded phenomenal until the platforms started to warp. Everything went awry. What to do?
I decided now on plexiglass. Plexiglass has to be supported all around otherwise it will sag. So I purchased a couple of 1" sheets of plexiglass put 1/4" cork between them, but only around the periphery 1 1/2" wide and another layer of 1/4"cork 1 1/2" wide under the lower sheet of plexiglass. Set up my turntable again and I have to admit that it sounds even better. Every thing seems to float.
I don't know if that helps but I think the secret is in isolating each level as much as possible and I think my borders of cork helped do the trick. So if you have granite and then wood try and set up a neutral barrier.
I live in a very old wooden house (1730} so you can imagine the floors are rather bouncy and vibrations from footsteps and everything else can have an effect. But with this set up nothing moves. It seems to work.
I have tried most methods mentioned and can only tell you that the 1" heavy granite slab with 1/4" cork and 1/4" rubberized pad purchased at a home craft store sandwiched with a 1" MFD board has done a great job eliminating all floor noise. depending where you finally rest the isolation platform might farther help to place it on a triangle vibrapod/cone or ceramic DH cone setup under the MDF as to the way I have achieved sonic details/dynamics with fantastic success and results.
I can guarantee that most of your very expense isolation platforms sold by companies to our hobby uses the same composites hidden in a laminated covering and market the finish which sells for 1000s of dollars.
Suspended tables will highly benefit from this application.
Reason is for the mere fact the suspended table truly has no plinth and get great support seating on rock solid hard platforms especially when suspended underneath the table with some cones.
Non-suspended tables on the other hand would not benefit from such a application and I would recommend a MDF board platform 2" in height box with a inserted cavity bladder such as a bicycle inner tube or fill the box with play sand sealed.
Again many company have manufactured same design application isolation platforms as mentioned for our hobby and have made tremendous amount of dollars marketing and then profiting big time on the finished products.
If you take a piece of granite (typically 18"x24" for a TT and at least 3/4" thick) and place it on a bed of sand (typically 3"-4" deep), and add a TT, the combination will way upwards of 30-50 lbs. I guarantee that tapping the granite with a hard object will produce no discernable ring. In fact in my case, such tapping is inaudible through the speakers on quiet passages. I suspect the same it true for bonding the granite with MDF. Try it.
Again, I have that exact setup with my Gavia and you can definitely hear any rapping on the granite, sandbox, stand, and in one recent case, on the concrete floor. I've now added Stillpoints between my gavia and the granite shelf. I think there is more to this than just the granite on sand. I believe the plinths on Teres and Galibier handle resonances a little differently so that could be contributing to the differences in our results.
Many Galibier owners use aluminum, 3/4-1", as a shelf on a bed of sand with great results. Makes sense since this is what Thom Makris recommends. He also finds that a similar thickness of MDF on sand gets most of the way to the sound with the aluminum. (Me, I went with the granite because of looks alone, so I'm left to compensate with Stillpoints.) It seems to me that experimentation is the only way to know what works. However, I don't know anyone who has a stand that they can rap on an not hear something through the speakers. I really don't think this is an issue because I've heard my turntable with a arm that had a significantly lower noise floor than my Triplanar and this did not reveal any flaws in the playback. Just the opposite in fact. However, on the other hand I would not claim that things are optimal.
Sometimes people get lucky and quickly find something that sounds good to them. I thought I was one of those, but prolonged listening convinced myself otherwise. I will probably build or acquire a different 'table stand at some point to investigate other approaches.