Granite Isolator Review

cjfrbw

Well-Known Member
Apr 20, 2010
3,323
1,313
1,730
Pleasanton, CA
http://www.graniteisolator.com/

Granite Isolator

I knew for some time as a matter of resonance hygiene that I needed some further treatment to isolate my SME 30 turntable. My sound has been generally excellent, and through laziness I just never attacked the project except to look at options from time to time.

The SME 30 has a robust built in suspension. It utilizes two stacked high density horizontal plates separated by rubber banded suspension pillars. It also has some isolation in the feet, either a choice of silastic inserts for soft surfaces or spring loaded ball bearings for hard surfaces. The theory is that the dense horizontal plates drain the vibrations from outside and inside the turntable into the 3 Hz tuned oil filled pillars. I had the feet placed on the silastic inserts on an older Nuance platform (no longer made, manufacturer didn't find he could make them cost effectively) on top of an end table.

I also have a concrete slab foundation, which theoretically takes care of vertical vibration components.

I do not use an audio stand for the turntable, but a sturdy end table, not high end as the photo shows.

Anyway, the resonance performance can be tested by turning off the turntable motor and lowering the needle onto the non-moving vinyl surface, and turning up the system volume, and tapping/ thumping at various locations.

In the PREVIOUS set up, tapping the top plate of the SME 30 resulted in a big thump through the system, as expected, tapping on the platter, vinyl, or top horizontal plate itself.

Tapping the "isolated" horizontal lower plate, separated from the top plate/platter by the pillars, resulted in a lower by 15-20db (ear estimate only, not measured) thump, indicating the feet isolation at work.

However, to a lesser extent, thumping the end table itself under the Nuance platform would also result in audible feedback. That is where I knew I needed some resonance hygiene. I have four subwoofers, and I like the bass hot and heavy, I can feel my body vibrating on playback, so I assume the turntable/stand can, too!

A resonance platform would need to hold the 100 pound weight of the turntable array.

These granite isolators are made for laboratories utilizing microscopes, lasers and sensitive weighing instruments, NOT AUDIO. They use some kind of specialty, hi tech silicon damping compound under the granite on a plastic shield. My sample arrived perfect. The granite is beautifully finished with nice 3D crystal, as nice as any high end granite countertop. My 16 by 21 inch model, for 140 pound weight, is about 1.6 to 1.8 inch thick. It weighs about 36-40 pounds. The 16x21 model retails for about $1000 sans tax/shipping. I managed to find a used one for $350. They come in several sizes and prices for different loads and sizes of objects. The silastic is supposed to be extremely durable, in excess of 20 years of life.

The manufacturer does not imply or suggest that these are substitutes for heavier and more elaborate air pressure isolation units, but says the are good for microscopes up to 1000x magnification. The manufacturer also says the use of the Granite Isolator in conjunction with air units will improve the air units' performance.

The Granite Isolator must have some limited self leveling and weight distribution, because after putting it under my Nuance/SME 30, the bubble level was perfectly centered without adjusting the feet of the SME 30.

Anyway, AFTER placing it, the tap tests ABOVE the Granite Isolator went as expected, with audible thumps from the top horizontal plate/platter, just as before. As expected , an attenuated thump from the lower plate, and even a bit more attenuation thumping and hitting at the newly placed granite surface above the isolation elastic pads.

However, robust thumps, knock, slams, opening and slamming the drawer/door etc beneath the elastic pads on the end table support resulted in silence. The Granite Isolator beneath the elastic pads effectively decoupled the wooden end table from the turntable array nearly completely as far as I could tell. No more thump there. Before the placement of the Granite Isolator, thumps to the end table resulted in highly audible feedback through the needle perched on the vinyl on the platter.

Trying to estimate the effect on the internal drainage paths of the turntable or the change in the fundamental tuning frequency of the array would require instrumentation and I don't have those.

Wiggling the Granite Isolator with the SME 30 in place, I would guess the horizontal isolation frequency at about 2-3 HZ just by watching it dampen over about a second or so. The vertical frequency is harder to estimate because it is difficult to observe.

As far as the subjective listening, I would say there is a noticeable improvement in bass definition as well as general clarity of the image THROUGH bass heavy passages. This results in a better CONTINUOSNESS to the music presentation. Given that it is perceptible from an already high performance system, I would call this reasonably impressive.

Another more subjective and less credible impression would be a bit of added upper midrange gloss to the presentation.

How the Granite Isolator compares with air units or spring units like the Minus K, I have no idea, I would imagine those sophisticated air or spring types would have some advantages. However, they also seem finicky as well as expensive. The vibraplanes (except the ELpF model) are extremely heavy, they require some monitoring with compressors, and anything with air and bladders tend to be subject to deterioration and lifespan problems. Having used compressors for decades in my profession, I am not the least bit interested in having them in my audio system.

The Granite Isolator is not cheap at it's retail price, but neither is it outlandishly expensive by audiophile standards. The Granite Isolator appears to be very effective, and is easy "place and forget", kind of like the SME 30 itself. The price ranges between some of the cheaper Townshend products and the much more expensive Vibraplane/Minus K types isolators. The Townshend products seem to be objects of relentless complaints concerning reliability over time and the air bladders being hard to manage or failing.

The Granite Isolator is worth considering for heavy turntables in the 4K plus price range in a care free oriented vinyl system, even though it is NOT an audio product. If it can offer improved resonance hygiene for a sophisticated, suspended turntable like the SME 30, it must be decent and it is pretty, to boot. I presume they can be used for any type of resonance sensitive type audio product as well, such as heavy tubed amplifiers, etc.
 

Attachments

  • P1010407.jpg
    P1010407.jpg
    502.3 KB · Views: 1,143
  • P1010408.jpg
    P1010408.jpg
    517.8 KB · Views: 1,307
Last edited:

PeterA

Well-Known Member
Dec 6, 2011
12,522
10,687
3,515
USA
cjfrbw, Congratulations and thank you for sharing the report and photographs. From the bottom image, it appears that you have four unique materials between the SME footers and the wooden end table. Are you saying that you had three and then added only the one granite slab and heard the improvements? Could you say a bit more about the object between the granite and the SME footers? And what is the purpose of that light blue foam insert below the granite and above the thin dark material resting on the wood?

The results of my SME 30/12 on a steel ballast plate on a Vibraplane on a DIY rack seem similar to what you report. Tapping anything below the Vibraplane results in zero sound coming from the speakers. One of these days I want to remove the drive belt to see if I can hear any motor noise through the speakers with the stylus on a non moving LP. I suspect that the four suspension towers do an excellent job of isolating the motor from the platter and arm board.
 

cjfrbw

Well-Known Member
Apr 20, 2010
3,323
1,313
1,730
Pleasanton, CA
I don't use a special stand. I found that tapping the platter, of course, induced resonance. Less resonance on the top plate, and even less on the bottom plate, negligible when tapping the legs. I think the internal bracing and vibration draining of the SME is effective for the internal vibrations of the platter/motor/spindle assembly. However, as stated, I could heavily rap on the stand and get feedback, especially when I thumped hard. Some of that depends on the resonance energies to begin with. Acoustic feedback energy from floor/stand/air when the system is belting out lower midrange and bass is going to be a lot more than the internal resonances, though the internal resonances are much closer to the needle. You have three things going on, the turntable internal resonances, the air impinging on the turntable itself, and the resonances transmitted through the feet. The design of the turntable handles, or "tunes" if you will, the first two, the stand the last.

I can't even remember the name of the "intermediate" device directly under the turntable, although it's purpose is to disperse, reassign frequency, and dampen resonance and it was popular many years ago, but the guy who made them got tired of the labor involved in making them and quit. Of course, when you have two materials with different properties, you risk establishing new resonant peaks rather than quelling, but I think that would be subject to testing the combos out.

The goo under the granite is the space age absorbing gel for the granite platform, and the thin platform under that is just the layer that holds the goo.

The "active" platforms probably work, I just don't think they are necessary to accomplish what is needed. Also, the idea of having another thing to plug in and that can break doesn't appeal, either. I can't argue that they aren't ritzy jewelry, though, if you are into that.

As you have noted, it isn't that hard to "test" the system with a needle on a non-moving platter and turning up the system to listen for feedback when clumping and thumping on stuff. I don't think any resonant energy from the floor/slab or air would exceed what you could do with your hands or a plastic hammer. I got the idea from Alastair Robertson-Aikman, who would tune things just by tapping around and listening.
 
Last edited:

PeterA

Well-Known Member
Dec 6, 2011
12,522
10,687
3,515
USA
I should have just clicked on the link you kindly provided to learn more about the three material granite isolator. Thanks for introducing this.

I completely agree with your observation that the SME turntable is designed to handle the first two, and I think to some extent the third. Additional isolation helps the third.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
What you have done is a classic turntable isolation approach: granite or marble underneath, plus some elastomer. I follow the same principle, utilizing granite, EAR Isodamp, Sorbothane and Stillpoints - quite effective and giving me the results you get as highlighted above. Congrats!
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
6,774
1,198
580
Boston, MA
Just realized we responded for the first time to a thread from 2013. Any changes since then?
 

cjfrbw

Well-Known Member
Apr 20, 2010
3,323
1,313
1,730
Pleasanton, CA
No changes, though you could also cite "cable resonance" from the tonearm cable, which I handle with simple bubble wrap where it seems to make contact, and bubble wrap under the Allnic head amp. I have bubble wrap under the motor, too, and any cables that contact, and they also immunize to taps and thuds around the items.

Bubble wrap is an excellent isolation device for low weight audiophile items, and I use it in a couple of spots, though I don't think that there are any audiophile brands (Har, Har!). Maybe I could start a brand and charge $100 per square foot.

The SME seems to have very little internal resonance that reaches the feet because of the oil impregnated pillars. With unsuspended turntables where there is significant vibration that needs to be drained through the feet, an isolation platform will stop reflected energies from going back into the turntable and allow the vibrations to "drain", so to speak, in addition to handling the vibrations from the stand/floor.

However, an isolation stand is not a complete cure for the turntable, which will still depend on its internal tuning architecture for the more proximate resonances above the feet.

My house has cement slab, which is supposed to be a pretty good drain, but I can feel it vibrating with my hand when the subs are going, so it is not acoustically inert.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing