[ Home | Staff & Contacts | DIY & Tweaks | Listening tests | HiFi Playground | Music & Books ]

Inexpensive Vibration isolation products group test

Part 4: Invasion of the blobby snatchers

[Italian version]

Product: blobs from Isonode, cones from Polychrystal & D.I.Y. vibration control solutions
Approx.cost: 19.99$ USD (set of 4 IsoNodes)
Reviewer: Mark Wheeler - TNT UK
Published: October, 2004

In parts 1-3 I summarised some of the problems caused by airborne & structure-borne vibrations on audio equipment in the domestic listening room. The effects of two affordable products designed to address these problems were compared on electromechanical source components, turntables in part 2 & CD players in part 3. Isonode soft anti-vibration feet were compared with Polychrystal composite vibration control isolators & some rival brands that use similar technological principles plus some DIY solutions too. A pattern did emerge correlating effectiveness of each type with certain applications, but I expected the findings to be very different with electronics.

One should not approach any review situation with preconceived hypotheses, and remain heuristic in approach, but inevitably ideas & theories begin to formulate with each finding. These ideas were not borne out which implies that this listener's ears & mind remained open.

I used the same scoring system across 20 parameters.

+3 denotes "wow, that's amazing" in that parameter

+2 denotes a significant improvement over the reference

+1 denotes the smallest perceptible improvement over the reference

0 denotes no reliably discernable difference

-1 denotes the smallest possible deterioration from the reference

-2 denotes a significant deterioration from the reference

-3 denotes "aargh, that's terrible!" in that parameter

This allows a range of seven possible relationships to the reference (stock-unmodified) condition in each musical parameter.

The numbers do not imply any objectivity whatsoever. These are purely subjective opinions of a sceptical music lover & some of his friends. The application of numbers is purely to apply some sense of the scale of the differences, and to help the writer spot patterns & correlations.

Equipment used ranged from an old Quad 44 onwards, but before the pre-amp locations could be assessed it made sense to optimise the power amps.

With a single-ended triode with outboard mains-transformer the differences were slightly more noticeable than with a big 100wpc solid-state behemoth. Both are home built with attention to mechanical vibration, the tranny amp weighs 24kg and needed 7 Isonodes to support it. The best combination supported those 7 Isonodes on a shelf standing on 3 Polychrystal Isolators and added 3 more Isonodes to the amplifier top-plate, supporting a weighty Jackson Pollock exhibition catalogue, chosen to be electrically & mechanically inert although artistically active.

The valve amplifier offered a bigger range of options, having the audio circuit in a copper-screened torlyte box (the one illustrated in Box Clever). Isonodes scored +14 & -1 (the -1 for stage depth) most improvements in the areas of vocals & treble. The Polychrystals scored +12, with gains in bass tunefulness, tautness & extension, whereas both improved dynamics and inter-transient silences.

Combinations of both products offer myriad possibilities, one Polychrystal & two Isonodes worked well under the amplifier section. Ultimately the PSU (power supply unit) was isolated by the Isonodes and the audio-section stood on Polychrystal, all pointing downwards. The glass shelf stood on both Isonodes & Polychrystals, the two alternatives sounding much less different here, and the combination even better. Much better than the stand's own plastic blobs or cork pads.

With pre-amps the Quad 44 was slightly improved by these products, the difference limited by the fairly opaque complex circuit, masked even further by the limited DIN terminated cables I had to use. The Isonode Anti-Vibration Feet were the winners with the Quad.

The biggest difference on a transistor pre-amp was on a Naim 42.5 board plus NA323 MM phono boards all mounted roughly in a 2U steel rack-case. The board stand-offs are cheap metal items. The whole thing rings like an old garbage-can. This would make Julian Vereker turn in his grave, but I installed it expressly to be a severe test of vibration effects.

The Naim 42.5 suffered in its ignominious home. A selection of cork pads and proprietary rubber feet made no significant difference; EAR squidgy feet (not submitted for this test but in stock) made a slight difference appropriate to their very low price. The Isonodes & Polychrystals made much more difference, but were almost equally different from each other.

[Naim NAC 42.5]
Naim NAC 42.5 preamp into the "junker" case

Although the raw scores were similar for both the Isonodes and for the Polychrystals in the 15-17 range, depending on position, the similar figures do not indicate how different they sound.

The Isonodes lifted several veils of noise and opacity right across the audible spectrum from bass depth to shimmering cymbals. Voices, particularly, sounded more evenly balanced with the Isonodes creating a more natural, less congested mental image.

The Polychrystals improved: bass tunefulness; vocals majored on embodiment; rhythm & timing were points ahead and soundstage more solid.

Both Polychrystals & Isonodes improved micro-dynamics (+1 point) and Macro-dynamics (+2 points). The various DIY solutions involving cork, sorbothane & silicone did not make any worthwhile improvements in comparison.

Combinations were then tried and the score raised a little when the butchered Naim was supported on the shelf by Isonodes and the shelf supported by Polychrystals. In this condition the shelf material became almost insignificant. The other way around was similar but the trial was inconclusive. Finally a brick (the kind used to build houses) was chosen as a non-resonant, non-magnetic mass-loading device. This was placed on 3 Isonodes on top of the 2U steel-case. The score leapt to 27, demonstrating that big differences are made to the sound when vibrational colourations are addressed, no matter how primitively.

So what happens when the Naim 42.5 is where it belongs. I also have an unmolested example of this fine, often overlooked pre-amp. The standard Naim product attempts to overcome vibrational problems by sandwiching an internal chassis of steel in an outer extruded aluminium sleeve and placing a sorbothane pad under the pcb. Perhaps the eddy currents in the aluminium and the hysteris effects in the steel tend to cancel each-other as the combination seems much better than each material alone. Whatever the explanation, the standard Naim (even through the DIN cables that I have to hand) was immensely superior to the standard steel 2U junker.

However, the fully loaded genuine Naim comprised the brick on Isonodes on Pre-amp on Isonodes on shelf on Polychrystal on frame; the soft Isonodes made better contact with the uneven crackle paint of the Naim than the harder Polychrystal material. I tried the Polychrystal Isolators the wrong way up to get better contact but the trial was inconclusive again.

Surprisingly the fully loaded standard Naim was only a little better than the fully loaded junker (with Isonodes wedged under the pcb inside too), which I had not expected. This demonstrated the effectiveness of these products at ameliorating clangy casework. Even allowing for the very ordinary DIN cables I was using with the stock Naim the better cased example was still slightly superior when the full panoply of Isonodes & Polychrystal isolators were applied equally to each. As an aside, Naim & Quad both note that DIN plugs are far superior to the horrible RCA phono-jacks that audio is cursed, but I only have DIN equipped OEM cables from Quad & Naim & RadioShack/Tandy, whereas I have a selection of superior wire with nasty RCA's on them. So the raw scores were not directly comparable between both setups.

What about tuners? The Accuphase T101 tuner of the 1970's is exceptionally well built and I did not expect to hear much, if any difference with any of the test items. Wrong. Both the Isonodes & Polychrystals made similar improvement as they had with the "real" standard Naim NAC42.5. There was little to choose between them & I finished with Polychrystals underneath & Isonodes-plus-brick on top. In this location the Isonodes were stuck to the tuner, curved face up.

I write that lot in the past tense as heavy Summer rain has just raised the environmental noisefloor beyond the point of critical listening. The system has reached the ultimate combinations of these products described below, so now as I write I am enjoying new levels of resolution while typing in rhythm to Grooverider's Drum'n'Bass.

[Naim NAC 42.5]
Naim NAC 42.5 preamp into the Torlyte case

Music Used in Part 4 was all on vinyl:

The Future Sound of London far-out son of lung and the ramblings of a madman

Little Feat Sailin' Shoes

Leos Janacek From The House of the Dead (Vienna philharmonic/Mackerras)

Little Feat The Last Record Album

Grooverider Mysteries of Funk

Lightning Hopkins Going Away

& that old audiophile favourite Jazz at the Pawnshop


Reducing the effects of airborne & structure-borne vibration on all the components audio systems really makes a big difference to the musical effect.

There seems to be no limit to the gains possible in trying to ameliorate the problems caused by vibration. There are even cable designs (and discussion on the TNT forum) being made to minimise the transmission of vibration via cable-structure from one component to another. My cd to pre-amp interconnect is very stiff (Sonic Link Vermillion) and I did disconnect this during the tests but I confess I could not hear a difference. TNT reader Thierry Yen Suin wrote to me in response to my Wood is Good article describing his own experiments gluing small pieces of ebony to components in his cd player, noting these had more effect than the expensive Shun Mook devices he had tried.
I will try this next now that my own cd player is housed in a non-resonant Torlyte case and has other sources of resonant & vibrational noise reduced. TNT reader & DJ Alexander Deoro wrote to me how he uses "wood cones with diamonds on top" under all his equipment. Furthermore all his equipment is in stone boxes on wood dampers to eliminate interior vibration and the internal parts are also "damped on diamonds" resulting in "a unique high level of harmonics from his speakers".

Vibration control interventions are cumulative. As more are applied throughout an audio playback system the effects add so that the total is greater than the sum of the individual parts.

The soft flexible polymer Isonode anti-vibration feet consistently made most difference to poor chassis. One level of decoupling proved most effective stuck to the underside of the chassis, plus one level of mass damping from above. However, springy or flexible decoupling techniques may clash destructively with other flexible systems. The Isonode anti-vibration feet did not work well with the turntable suspensions. positioned both above & below a shelf they were less effective than positioned between chassis & shelf with Polychrystal Isolators between shelf & support. The effect of the Isonodes was inversely proportional to the mechanical integrity of the product. Better built components were less improved by Isonode support than cheap rattly casework, but almost every commercial non-suspended product sounded better on the Isonodes.

The Polychrystal Isolators worked better with components that are already reasonably non-resonant & in these applications seemed to go further. The components that were mounted in better cases (wood & Torlyte) sounded different on the Isonodes than on the Polychrystal cones. Both products were better than any of the alternatives, and scored similarly to each other overall, but they emphasised & improved different aspects of the playback experience.

Generally the Bright*Star Isonode anti-vibration feet majored on lowering the noise floor, improving treble purity & clarity, and especially rendering voices more realistic & natural. This applies under amplification & cd players & analogue tuners. You should install one set of them directly under the casework of any steel or aluminium cased audio component.

The Polychrystal Isolators majored on bass tunefulness & tautness, rhythm, & soundstage solidity, while also lowering difference noisefloor spectra than the Isonodes. You should use a set under any component that has inbuilt suspension or a well built non-resonant case.

Better still, use a set of Isonodes between clangy-cased components & their shelf, plus a set of Polychrystal Isolators between the shelf & its support. The cumulative effect is greater than either set alone.

Electro-mechanical components (especially cd players) with well built non-resonant casework placed directly on Polychrystal Isolators produced a sound that I personally preferred, emphasising the flat-earth qualities of PRaT (pace rhythm & timing). A second set between the shelf & support brought further benefits, this time in the noise floor across the spectrum, but Isonodes between the shelf & support brought gains in vocals & high treble. On top of any case a combination of house-brick & Isonodes wrought further improvement. I did not try different kinds of brick because I am not that sad.

Purely electronic components (tuner, pre-amp, power amp) in clangy cases benefitted most from Isonodes, preferably two sets, one each above & below the component. This applies equally to those with external power supplies. If the amp & PSU share the same shelf, they should both be supported by Isonodes, and the shelf also supported by Polychrystal Isolators or Isonodes if the frame is very resonant.

Better DIY casework is not going to cost much and seriously outperforms any add-on products and is a vital step in the direction of the ultimate set-ups that I have found. Do not consider it unless you have a comprehensive understanding of electrical safety & even then have it double checked by someone professionally qualified. But it's easy to make things much worse too, and I confess that the reason you didn't read about trying the Naim 42.5 in a non-metal box was that I could not eliminate hum & noise problems.

Valve power amplifier (non-resonant case) with external Psu: Amplifier on Polychrystal Isolators on shelf on both types on support; PSU on Isonodes on shelf.

Naim NAC42.5 (internally damped circuit board) on 1 Polychrystal Isolator (point up due to Naim textured paint) & 2 Isonodes; on shelf on both types on support; PSU on Isonode Vibration Control Feet on shelf on Isonodes on support.

Valve pre-amp on Isonodes on shelf shared with PSU on Isonodes on shelf. Shelf on Isonodes on support.

Having the power supplies on separate shelves is another step. Then use Polychrystal Isolators under the non-resonant chassis & Isonodes supporting the power-supply. The more your system is subdivided by function into individual boxes, the better these techniques work. However this makes for a much bigger system with far more wiring, and therefore far more opportunity for electrical noise to enter via the connections. The choice is yours.

Readers who buy a couple of sets of each of these products will spend a few happy evenings experimenting and then enjoy results that are more cost effective than replacing all their cables. I suspect they will then buy more until the whole system is treated. Once optimised the difference was similar to upgrading an amplifier. Happy listening.

[Rewind to Part I] - [Rewind to Part II] - [Rewind to Part III]

Manufactuer's comment from BrightStar Audio (IsoNodes)

We would like to thank Mark Wheeler for writing and Lucio Cadeddu of TNT-Audio for publishing the review of our IsoNode anti-vibration feet. Of course, we are very pleased that Mr. Wheeler found that, "The Bright Star Audio IsoNodes do the best job of ameliorating the problems of structure born vibration and of acoustically-induced resonant vibration in the player," and that he said, "I would strongly recommend the IsoNode anti-vibration feet."

We are very proud that the IsoNode feet have been voted "Product of the Year" by Enjoy The Music, "Best of CES" by Audio/Video Forum and listed in the "Top Five" by Mix Magazine in their AES new product roundup (out of 300 products). Over the last fifteen years our products have earned worldwide recognition and numerous industry awards and nominations including "Accessory of the Year" by Stereophile (four times), "Best of the Year, "Editorís Choice", "Best Buy", and "Cream of the Crop" by The Abso!ute Sound, "Component of Merit" by Bound For Sound (five times), the "Golden Note Award" by The Academy (three times), "Product of the Year" by Soundstage!, "Editorís Choice" by Fi Magazine and many others. We manufacture a wide range of vibration control products and equipment racks to accommodate virtually all equipment and any situation.

The fact that Mr. Wheeler did take the time to retest the IsoNode feet after Part II was published does show his dedication to a thorough review process and we thank him for doing so. I would like to point out that Mr. Wheelerís conclusion about the performance of the IsoNode feet under turntables with suspended sub-chassis only refers to the two models he had on hand for testing (Michell Gyro SE and Thorens TD160S) and as used in his particular set up. We have had a large number of very positive reports from consumers and dealers about the improvements to most turntables with suspended sub-chassis when the IsoNode feet are placed underneath. Turntables without suspended sub-chassis as well as CD/DVD players and other components will also exhibit significant improvements with the addition of the IsoNode feet. We also manufacture dedicated platforms for a number of high end products including Basis, VPI, Well Tempered, Micro Seiki, Jadis, Atma-Sphere and many others.

We do ship IsoNode feet worldwide and invite audiophiles and home theater enthusiasts to visit our website for full information. Please feel free to contact me personally if you have any questions.
Best Regards,
Barry Kohan - President - BrightStar Audio

© Copyright 2004 Mark Wheeler - www.tnt-audio.com

[ Home | Staff & Contacts | DIY & Tweaks | Listening tests | HiFi Playground | Music & Books ]