Symposium Acoustics Isis racks/isolation

spiritofmusic

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Jun 13, 2013
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Greetings, What's Best afficionados. Just thought I'd start a new thread on the recent changes I've made to racks/supports/isolation. An overview to begin, and happy to answer any qs.
Always had great results improving power in my system, culminating in current 4kVA balanced power and Entreq Silver Tellus grounding (see my Entreq thread in 'general audio discussions'), but less clear cut results with racks, even after auditioning HRS and Grand Prix Monaco. However I picked up a used 3 tier Symposium Acoustics Isis rack with upgraded Ultra shelves, and a couple of Svelte Shelves for under spkr duties, and finally started to "get" the advantages of isolation.
The system works on the principle of alternate layers of stainless steel and absorbent foam to disrupt vibrations, and Rollerblock modules (ball bearings in magnetic cups), both BETWEEN shelves in the rack to isolate individual components from each other, and the floor, and UNDER individual components to isolate each shelf from the effects of component-borne vibrations. Rollerblocks btwn shelves I'm using, but not those under components just yet, except for four under the corners of the bases of each spkr.
So, the sound. Well initially a little disconcerting - a reduction in haze and grunge, but a seeming thinning in bass, mostly attenuated by the modules under the spkrs. I find these aspects of upgrades so hard to work out if an advantage, since warmth always seems to go missing.
48hrs later, and the sound clicks into place - what appears to be bass MIA is in effect euphonic bloom gone. Now I'm aware of fretwork, and the leading edge of bass notes finally clearly delineated, but with full harmonic decay, hence the true warmth of the bass end finally revealed with much reduced cloying.
Such an interesting result, and complementing my recent Entreq grounding to really reveal the true musical message.
My next port of call is to place Rollerblocks under each component to take passive Symposium isolation to it's logical extreme.
My desire to go down the Stillpoints Ultra 5s route is gone now. Luckily since a full system complement would be over 3x the cost of Symposium.
Mark me down as a convert to effective isolation.
 

MylesBAstor

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Apr 20, 2010
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Actually I think it's aluminum.
 

spiritofmusic

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Jun 13, 2013
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We're both right, Myles. Isis stand is solid aircraft grade Aluminum, the Ultra/Svelte shelves are stainless steel-foam constrained layers.
 

spiritofmusic

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Jun 13, 2013
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Getting amazing results now with Isis. Most particularly not just the rack, but the Rollerblocks under the spkrs. Who'd've thought that allowing the spkrs to wobble within controlled limits would be preferable to fixed spiking to the floor?
 

audioarcher

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May 6, 2012
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Seattle area
Getting amazing results now with Isis. Most particularly not just the rack, but the Rollerblocks under the spkrs. Who'd've thought that allowing the spkrs to wobble within controlled limits would be preferable to fixed spiking to the floor?

Hi Spirit, I also have tried rollerblocks under my speakers. Initially I though it was a good thing but I found issues with the bass response. I am interested in what you think of it after you have lived with it for a while.
 

spiritofmusic

Well-Known Member
Jun 13, 2013
14,602
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E. England
Sean, the biggest dilemmas I have with upgrades are when there is a seeming decrease in bass esp re warmth. So, when I duly placed the Rollerblock Jrs HDSEs under my Zu Definitions 4s, that's exactly what I got - the sound was more transparent, but seemingly wispier and less grounded, less warm. I got exactly the same change when I tried active isolation under my tt.
However I persisted with the setup, and the sound did change a little, but I actually found that I reinterpreted the sound after a while. What I thought was wispiness was I consider now a reduction in euphonic bass haze. I do believe I'm actually getting my previous bass weight, but notes start and stop better, allowing less cloying further up the frequency range. But I fully accept that this function may not be that positive with every other spkr out there.
Please note i've rejected as many changes in my system as I've accepted if I feel the avenue gone down is not beneficial, so I've not just taken the tweak at face value.
The nearest parallel I have is moving from my prev belt drive tt/pivoted tonearm (Michell Orbe/SME V) to my current direct rim drive tt/air bearing linear tracking arm (Trans Fi Salvation/Terminator T3Pro) - again transparency was achieved at a seeming defecit in bass warmth, and then I "got" the change: more accurate, less euphonically coloured bass).
 

theophile

Well-Known Member
I also like the 'cup and ball' method of component coupling. Beneath my turntable I utilise: diy cup and ball directly in contact with stainless steel plates which sit flush against the plinth-bottom's sides. The cups I currently use are ceramic. I have commissioned a precision machinist located within a mile of here to make me 4 perfect polished cups out of 7075 aluminium. The ball and cup setup sits on a Granite piece about 1.25 inch thick and 20 inches by 17( l and w). I glued some outdoor carpet to the base of the granite in order to be able to(with a lot of effort) slide the combination of 100 plus pounds of GT 2000 and granite piece around on the perspex shelf member.

The perspex shelf member itself sits atop 21 Clearaudio Magix. I had the perspex cut to be circular and the 21 Clearaudio Magix are arranged in a circumferential support of that circle. The support is designed to utilise the Magix around the perimeter with the load in the center. I have never seen anywhere anyone who uses the Clearaudio Magix in this manner. The combination of cup and ball coupling with its horizontal freedom and the vertical isolation of the Magix provides a very significant leap for the GT 2000's sound quality.

I've tried almost this same setup without the cup and ball and I end up liking the inclusion of cup and ball more than either solution used on its own.
 

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