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TNT-audio's own designs tested against the best

Mark's saga:
The eighth instalment of the vibration control epic odyssey
Great pyramids of geezer
[Italian version]

Product 1: Canadian foot pumice
Product 2: Canadian foot pumice
Approximate cost: $2Canadian per pack, yes, really!
Product 3: cork blobs
Approximate cost 1€ per pack
Product 4: incense cones
Approximate cost 2 or 3€ per pack
Product 5: tap (faucet) washers
Approximate cost 3 € for three
Supplier: Local pharmacy-drugstore-chemist; ironmonger; diy store; your loft (attic);
Reviewer: Mark Wheeler - TNT UK
Reviewed: June, 2005

If we cannot be FREE, at least we can BE CHEAP

Frank Zappa

The Judeo-Christian belief is that the entire universe was created in 6 days and on the seventh their deity rested. Your humble scribe, being a mere mortal has already spent 7 episodes merely exploring the benefits of vibration control before creating anything at all. So, on the eighth day...more vibration isolation products.

Manufacturers at all price points are turning increasing attention to vibration control as our Maarten van Casteren's visit to the Arcam factory highlighted "With the CD36 [2300E] we also spent quite a bit of time optimising the vibration damping".

Part 7 of this saga reviewed the least expensive products of the series so far, the $2.95 Polycrystal Point Discs. Today we're hearing the bargain basement.

Many months ago I was contacted by Canadian TNT reader, Yves Levasseur, who wondered if I had compared any of the 'budget' vibration control products with the DIY solutions published on our own website. I was feeling rather stupid as I admitted that the idea hadn't occurred to me. I read the Stone Blocks articles and nipped round the corner to my local chemist shop (or pharmacy or druggist in other parts of the English speaking world), only to find nothing like the products described in Lucio Cadeddu's and Mimmo Cacciapaglia's excellent article.

"Today was shopping day for you, and I found 2 different pumice products. The lighter one is the one I use in my system. The second one if a bit more heavy. I didn't try it yet but I will soon. You will receive both of them. The heavy one intrigued me and it was bought because of your article on the polycrystal. This second pumice being more dense / less air remind me of the dense polycrystal.
A la prochaine,
Yves Levasseur"

Yves mailed me the products he had bought in Chicoutimi, Quebec, and he refused to accept any repayment. The global audio community is both friendly and generous. The products arrived to Heather's enquiry "why is someone sending you footcare products from Canada?". They were quickly remanufactured into Stone Block Variations Mk1 & Mk2.

My TNT-audio stoneblocks Mk1 I have are a stiff, but friable blue foam (some kind of polyester perhaps?) and Mk2 a grey granular material with different sized grains embedded within.

Readers must know by now that my cameras rest on tripods not quadrapods and my audio gear rests on three points too, unless the isolation product is compliant, when the best number is usually the one that best damps the vibrations thoroughly. Stone Blocks are solid, so three points will be better than four. I have noticed that different products work differently in different places under each piece of equipment and sometimes work better with a big area in contact with the component and elsewhere work better with a point contact to the component. The original Stone Blocks were square, but I decided to try them as triangles to have the opportunity to test the points-up vs points-down condition, in case that might make a further difference.

There is a difference between the effectiveness of points-up vs points-down, and it depends on the equipment being supported. Oh yes! Here is another variable in the tweeker's armory to add to your audio-paranoia. Readers really do need another thing to worry about in their system set-up so who am I to disappoint you? Most things worked better points-down, with the flat side in contact with the equipment chassis and the point on the shelf, but some were the other way around. A key place where the point works better is the centre bolt of a toroidal transformer. BUT frame transformers are the other way around in this test, seeming better supported by the flat side. Ho hum...this audio lark is enough to cultivate obsessive-compulsive disorder.

Clockwise from the blue ones
Blue brittle abrasive foam
Typical product original feet (Rotel rubber & plastic)
Non-audio furniture adjustable foot
M6 hardened steel spike & insert
Tap (faucet) washers, hard & soft
Square stick-on instrument feet
Coloured incense cones, below-
Self-adhesive cork & rubber glass-separators


I have tried many shelves in the past, both on audio tables and wall supports, but also another furniture stands, a favourite range being from Wilkinson (a.k.a. Wilko) the British ironmongery & homecare products chain of stores. I have to tell you, dear reader, that most of what you read on this subject is bilge of the lowest order, mainly due to a lack of thoroughness by the writers. How many times have you read that glass shelves are coloured, or sound "glassy" (whatever that means) or bright?

Firstly, there are many different types of glass, more different in audio performance than similarly priced mid-budget integrated amplifiers.

Secondly, all domestic glass is hard surfaced. My experience is that any hard surfaced material sounds terrible on four point supports, especially 4 steel spikes. One spike is always under less pressure than the other 3 and consequently tends to vibrate, causing typically coloured bright sound, and high listener fatigue.

3 points of hard contact or a compliant support type (the BrightStar Isonodes, reviewed in part 3 are ideal under glass) eliminate this problem. Now the glass can be compared. Tempered glass (the kind usually supplied with furniture in the EU) rings like a bell when tapped and does sound differently coloured compared against the typical veneered chipboard shelf supplied with audio supports. If you have tempered glass shelves on your audio rack, do try a lossy product like the Isonodes to hear how much the shelves are adding to the sound. This is glass-tuning stage 1.

If you're after more performance, and don't mind spending some more money, a visit to your local glass-merchant is necessary. Order "Laminated Glass" in the sizes needed to fit your rack and your equipment. Laminated glass comprises two layers of glass joined by a constrained layer of some very strong transparent flexible material. It is designed to hold a large window together if it is struck with force. I have seen its strength demonstrated with hammer blows. The two glass surfaces shattered but the sheet remained intact in the frame, supported by the inner membrane, demonstrating its strength and its adhesion to the glass layers. It is this adhesion combined with its flexibility that is of interest to us audio casualties. 'Tempered' or 'toughened' glass is designed to shatter into small granules with minimal sharp-edges and so it is much safer, especially if your toddlers (or Animal House style frat-buddies) like to amuse themselves by head-butting glass table-tops. When laminated glass breaks it does shed shards of sharp-edged glass, so if you have frat-friends:

  1. Keep them out of your audio room
  2. Get some grown-up friends

A sheet of 12mm laminated glass is a very heavy inert shelf. It does not ring. It is more rigid than chipboard, mdf or most natural woods (other than certain tropical hardwoods or swampwoods like lignum vitae). It also retains this rigid behaviour to much higher frequencies than composite timber products. It is cheap by audiophool rack standards.

In use, laminated glass (6mm or 12mm) produces one of the least coloured sounds of any of the shelf materials I have tried. I now use a 12mm thick laminated glass sheet (550mm x390mm) on my Origin Live Ultra wall support with my Michel Orbe, where it is les coloured and much clearer than the original Origin Live 18mm dense fibreboard 'Ultra' triangular shelf. That original was chosen by its designer, Mark Baker, after much research, for its superior performance to the alternatives he tried. The laminated glass sounds faster and cleaner than the original, and also did so with my Linn Sondek, which is a deck notoriously sensitive to shelf materials (except where fitted with a Trampolin base that sounds truly dreadful on any support compared to the old hardboard original).

Laminated glass (6mm this time) also outperforms the chipboard shelves supplied with my 1987 Appollo wall shelf, standing on stoneblocks under my Rotel RCD965BXdiscrete and standing on Isonodes under my pre-amplifier. BUT there is one other shelf in my armory that sounds surprisingly similar (especially considering their very different pedigrees) under many audio components. It is an ultra-lightweight shelf made by Mark Orr as an early prototype I got from him in 1990. It is as light as Russ Andrews' Torlyte, which is a web of thin wood spars faced by thin wood sheets. However, Mark Orr's prototype is a solid block (of end-grain balsa-wood) with a skin of stiffer material.

The main problem with laminated glass is its enormous mass. Because it is laminated, this mass is rarely moved to resonate (demonstrated with a contact microphone), but in certain applications it can seem slightly turgid (never as turgid as mdf) compared with Mark Orr's lightweight shelf.

So I usually have laminated glass under my turntable and my cd player. I tend to use the ERaudio SpaceHarmoniser platforms under anything with valves inside as there seems to be some symbiosis between them & tubes from B9a to Octals and power-tetrodes. For this test today I eschew all expensive jiggery-pokery and use the cheapest support options available, because the impoverished diy enthusiast will not be combining 2€ footcare products with 200€ shelves. So even the laminated glass gets removed and replaced with the original tempered glass that rings discordantly like a cracked bell. That sits on cheap cork discs on top of the cheap steel frame from UK low-budget diy giant Wilko. The square section legs are filled with kiln-dried sand that already raises the performance of this 90€ 3-shelf unit to near 300€ levels.

The Consonance cd120 currently in for test is unusual in that it does away with the usual digital domain brick-wall filter, and even omits the steep analogue filter that sometimes substitutes. It has a valve output stage too, just to add microphony potential, and its power-supplies are all inboard, offering another opportunity for vibrational interference. Despite its solid casework, this Consonance player superficially appears to have many of the ingredients for a vibration sensitive electro-mechanical product. Perfect for this excercise.

Cutting Stoneblock Variations with saw

The Consonance output is fed to a variable transformer and then direct to the Dyer Audio Systems Harefield active monitors currently in-situ should be revealing enough to highlight the differences between these vibe-control solutions, as well as playing at high enough levels to induce acoustic feedback effects in my room.

Looking at the various products in front of me, the appearance of each leads to a priori expectation. This psychological effect is one of the reasons why double-blind A-B testing is so often proposed by audio authors. I did establish that I am not very suggestible in part 1 of this series, but who knows what detrimental effects increasing age and audiophilia nervosa have on my psyche. I am expecting, while sawing them into triangles, the bright blue friable blocks to be less effective than the grey blocks because of their appearance. The grey blocks appear to have varying sizes of granules, exactly as claimed by 'proper' audio cone manufacturers, while the blue blocks just appear to be some kind of foam stuff. I also expect them to be broadly similar, with the grey simply outperforming the blue in certain parameters.

My 24 parameter scoring system is needed for this type of test as it is too easy to forget all the subtle differences. With Lee Perry pumping the dancehall with early 80s style electronica the blue scores plus 13 over the Consonance's own feet, but the grey manages just 12!

This is not as simple as it seems as they both score in different parameters. This is not A-B testing as the album gets played through rather than difference exaggerating back-to-back track-by-track and the I play the reference standard feet in between, to recalibrate my ears. The surprise is not that my preconceptions are proved to be wrong, but that they are not more similar. I listen again using the highly successful Polychrystal Isolators as a reference between each play and once again at the end. The expensive audiophile product scores a consistent 4 point improvement over each of the footcare products, which also does not make sense. Interestingly, when compared with the standard feet, the Polychrystal scores equal the best of both worlds of each of the stoneblocks making a total 17 (tho this would be just 4 more than the blue compared to the standard feet). The blue presents a slightly deeper soundstage than either the grey or the Polychrystal. Confused? You should be.

The blue and the Polychrystal manages plus 2 for rhythm over the standard feet whereas the grey manages plus 1. The grey and the Polychrystal manage plus 1 for micro-dynamics where the blue fails to score. If you must have the best of all possible worlds you do need to buy the pukka audiophile product (I have), but if your budget has higher priorities elsewhere (like more cds) the home-made alternatives will be enough for a while.

The 4 layer cork-rubber-rubber-cork stacks (looking like Bassets Licorice Allsorts) scored plus 4 over the Consonance standard feet, so really don't manage enough to justify further trials. They are often useful between shelf and frame though, at a mid-point between spikes to reduce vibration in the unsupported zone.

Looking at the hifi products on the market I had another idea. Incense cones. These appear to have many of the attributes of audiophilia. While they lack snake oil they do feature all kinds of fragrant exotic oils from many plants. They are ready made into a round-topped cone shape. Above all, they are cheap.

Performance? Stunning for the price. They come quite close to the Polychrystal Isolators, which means they are better than any rival audio hard-cone solid product I have tried (including various metal, wood or composite types. The incense cones score 17, equalling the Polychrystal total, but in different parameters. The incense score an extra point in both treble clarity and midrange intelligibility. The incense cones lose out to the Isolators on rhythm and micro-dynamics. This is an amazing performance from something so cheap and commonplace.

There is a downside. Whereas most of these hifi products claim to work by converting vibrational energy into heat, or referencing it to ground, the incense cones seem to attain their spectacular midrange and treble clarity by gradually crumbling to dust as the vibration is absorbed. Like all the other products, I employed them point down, with the flat side to the component chassis. This was quite a balancing act itself. On inspection, after just 1 cd, about 3mm has collapsed. I insert a new set and examine them carefully. They look complete before a cd is played. At the end of it they too are about 3mm shorter with a flat disc-face where the point had been.

Having built up some experience of each type I try the blue and the grey back-to-back just one whole cd at a time to be sure. This method exaggerates differences rather than similarities and is usually irrelevant to audio shopping, but a reality check for this excercise. Arvo Part's Spiegel Im Spiegel has the opposite rhythm effect to Lee Perry. Now the grey is better, but only just. The blue has slightly sweeter high treble and less 'fuzziness' but the grey presents a more convincing soundstage and retrieves more ambient information, but all these differences are 1 point each, which represents the smallest possible discernable difference. In other words, there is hardly any difference at all.

if we cannot be FREE...


My preconceptions were disproved by these products. Footcare does have a role in hi-fi, but the brand is relatively unimportant. Both skin-abrasive products worked very well. So well indeed, that if they were marketed as audiophile products at less than half the price of the Polychrystal Isolators they would represent good value in the audiophile scale of values. Remember that the Polychrystal Isolators were the best of their genre (solid cones), outperforming a well established European product. Indeed, our local European product was no more different from these pumice blocks that they were from each other.

My previous recommendations still apply: clangy casework needs lossy damping; electromechanical devices (like cd players) with good solid chasses benefit from stiffer supports utilising different technologies.

If you have not already begun your own vibration control odyssey, here is a cheap place to start. Read all the TNT diy pages and try the low-cost diy approach before deciding whether it is worth your hard-earned cash to go further with commercial products. With ingenuity some diy solutions are the equal of some commercial products, only bettered by the best that R&D departments can develop.

Now I just need to find some DIY substitutes for the excellent Bright*Star Isonodes to test...
now where do I begin...

Music enjoyed during this review

  • Arvo Part: Alina, ECM 1591 449958-2
  • Arvo Part: Beatus, Virgin Classics, 7243 5 62205 2 2
  • Lee Perry: A Serious Dub, Music Digital cd6107
  • Frank Zappa: Cheap Thrills, Ryko RCD10579

© Copyright 2006 Mark Wheeler - www.tnt-audio.com

What you may have missed on the vibration control voyage:
Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6 | Part 7

© Copyright 2006 Mark Wheeler - www.tnt-audio.com

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