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September 2006
Enjoy the Music.com Review Magazine
Sound Dead Steel Revisited
Review By Rick Becker
Click here to e-mail reviewer


  This is the stuff mothers warn their daughters about. It is also the material certain manufacturers would rather you and other manufacturers didn't know about. It is potent, as well as potential. In the review of Sound Dead Steel's Isoplatmat turntable in the June issue, I gave it a rave review, calling it "world class," falling to the more accurate side of the Boston Audio Design Mat 1, which presents a more lush sound on my Linn turntable. But inquisitiveness led me to investigate the use of the material on the bottom of the Linn, where it performed even more superbly, dropping the noise floor and surface noise into the cellar. I've reviewed way more than my share of vibration absorbing shelves and footers and I recognized that this material was really something very special. I begged for more.

Les Thompson, Chief Audiophile and owner of SDS, was sufficiently impressed with my review that he ordered up a bunch of raw cut 3" squares of the Sonphonon material. He also sent along a large, finished plate and a stainless steel version of the Isoplatmat turntable mat. All this is mere child's play for a large company that specializes in the manufacture of industrial structures featuring outstanding noise abatement properties.

But it is the child within an entrepreneur that is creating these marvelous toys for the high end audio arena and the potential for the industry is huge. Listen up.

Let's get the stainless steel Isoplatmat out of the way first. It is beautifully finished with a precisely cut, but not razor sharp edge. The name Porsche came to mind as I looked at the highly polished pewter-like finish. This is a 9001:2000 certified company. Like the powder coated aluminium version I previously reviewed (click here), it was still slightly too large to drop inside the outer lip of the Linn platter. Les assured me that the next production run of mats would be downsized a millimeter or two so that it would drop right in. That change will also assure that the mat will fall within the raised outer ridge found on many 12" LPs. That spells progress to me. But there was a significant problem I hadn't foreseen. When I placed the stainless steel mat on the suspended table, the Good Ship Sondek listed heavily to port. I cried out, "All hands to starboard"! But even that didn't help.

Actually, the platter dipped heavily toward the back corner of the turntable. The three springs that suspend it could not counteract the additional weight of the heavier stainless steel Isoplatmat and the ERS Record Clamp. The back edge of the platter bottomed out on the stainless steel chassis of the turntable. Not good. When I removed the Record Clamp the platter cleared the deck, but still listed to port. I wasn't about to tear the Linn apart to install stiffer springs to support the heavier stainless mat, so I forged ahead and played a few LPs anyway. The sound was very similar to the excellent results I achieved with the aluminum version. The differences were so small that they could easily be attributed to the tilt of the table rather than the different material of the mat. I would need to find a non-suspended table to compare the two.

I turned my attention to the three-inch squares. Sonphonon is not an easy material to work with. You can't cut it with tin snips; it must be cut in a heavy press, which can leave it with sharp edges and a slight bulge at the perimeter. This was the way it was sent to me, so I headed for my workbench in the cool basement on a warm summer day. I actually enjoy working with my hands, taking great pride in being able to use manual tools rather than resorting to a Makita. With eleven squares, I filed each side from the left, from the right and then straight across the edge to assure there were no rough edges to cut my self or scratch any components. Oh, and I didn't forget to round the corners, either. That amounts to 132 lines to file, and 44 corners to round off, which might begin to sound like Product Development to some, but I was driven by the anticipation of discovery.

You see, this material is only about 3mm thick, a feature that is both a positive attribute and a negative one. On the down side, you cannot achieve maximum benefit by merely setting a CD player or amplifier on the squares. The feet of most components do not transmit or suck out vibrations from the component as well as the SDS does when it is in direct contact with the chassis of components. For the 3" squares to contact the bottoms of the components, they must be held up by blocks or other footers to raise the component high enough for the feet to lift off the shelf. I tried small wood blocks and aluminum blocks as well as well as more sophisticated footers such as the Boston Audio Design TuneBlocks and Symposium Acoustics Roller Blocks in various shapes and sizes. Wood and aluminum blocks worked OK, but there was an additional benefit when the SDS squares were combined with the TuneBlocks or Roller Blocks. If you already have sophisticated footers under your components, don't consider them obsolete. Combine them with the SDS and you will be at, or very near, the State of the Art in this category.

The principle function of the SDS material is to quell the micro vibrations from the components, converting the mechanical motion to heat in the middle layer of visco-elastic polymer sandwiched between the thick and thin layers of stainless steel. These vibrations are generated not only by music pounding on the chassis, but also by the electricity passing through the circuitry and the whirring motion of turntable and CD platters. Even the building housing your system can transmit vibrations, though these are usually at very low frequencies.  The fact that Vibraplanes are frequently used under laboratory equipment suggests that these vibrations are not insignificant, and the benefit of using Vibraplanes under audio gear is documented in a number of articles. Vibraplanes, however, are large, heavy and expensive. On the plus side, the SDS squares are so thin that they will be out of sight, or at worst, very inconspicuous. The SDS material is also considerably less expensive than a Vibraplane so it should be affordable by all but the most destitute audiophiles.

We have all seen examples of manufacturers who try to combat these vibrations by building massive chassis with thick walls and beautiful, but expensive faceplates. But as I mentioned in my previous article, the closer to the circuitry you can apply the anti-resonance technology, the simpler and more cost-effective it can be. Witness the excellent and affordable Herbie's Audio Lab HAL-O tube dampers. At least two major manufacturers, dCS and Arcam, already have incorporated SDS directly into their components. In both instances these components have received critical acclaim.

And while neither component may be inexpensive, the SDS was only one of many factors that play into their high cost. Certainly, the competitive advantage achieved with the SDS material accounts for part of the price. These manufacturers would be foolish to give away the improved audio quality for free. That is not the way capitalism usually works, unless, perhaps, you are trying to buy market share. Whether or not capitalism needs a new competitive model in the absence of communism is the subject for another journal, but keep your eye on China.


Size Matters

I requested 3" squares because I suspected there was a correlation between the amount of area and the effectiveness of the SDS: the more area, the more effective. But too much area has serious drawbacks, too. You don't want to cut off significant amounts of ventilation coming through the slots on the bottom of the chassis. You also want to be able to place the material flush to the bottom, avoiding the heads of protruding screws in order to increase the contact area. There were some instances where I could have used 1" x 3" or maybe 1.5" square pieces for optimum placement, but since I don't have a way to cut the material easily, I didn't venture any further in this direction.

I did put them to other uses, however, namely, with loudspeakers. At a friend's home they made a very significant contribution to his stand mounted Spendor loudspeakers. Unfortunately, his stands had small upward facing spikes which prevented a more evenly distributed force against the bottom of the loudspeakers. In this case, as single plate, cut close to measure, would have been preferable to the smaller squares. Nonetheless, there was a recognizable improvement in the focus, a drop in the noise floor, and a more holographic and palpable musical presentation. And these perceptions were from kneeling off to one side of the sweet spot. Had I been centrally seated, I probably would have noticed a more articulated soundstage as well.

Bringing the squares back home, I placed them under the spikes of my Kharma loudspeakers that, at 150 pounds apiece, normally pierce the carpet and dig into the suspended wood floor. There was an improvement in focus from top to bottom and a quieter noise floor in general. Since the rest of my system was already finely tuned, this was not a jaw dropping improvement, but certainly a very worthwhile one from both an acoustic and a cost standpoint. In a less well-tweaked system the effect may seem more profound. Moving into the family room where the video rig is located, I placed the squares under the spikes of my beautiful Coincident Technologies Partial Eclipse Mk II floorstanders. The SDS literally brought them back to life, bringing the focus up to today's higher standards and obscuring the fact that I was using a cheap DVD source and an old Tandberg integrated amplifier.

The changes brought by the improved focus always made a contribution to the music. A recent article within a print magazine the reviewer identified TMI as the situation where a system gives you Too Much Information and degrades the musical listening experience. This is an important observation and recalls a familiar situation to which most of us can relate. Do you remember installing a component or loudspeaker that was so much more articulate than the other components in the system? And the music became worse instead of better? Today, there is lots of great gear at ever-lower prices and the probability of a rig sounding really terrible is diminishing. Certainly, some components still sound better than others. Perhaps these devices, in concert with very top-level high-end audio components, can make using TMI a significant danger. But for most of us, and for most equipment in use today, an improvement brought about by SDS or other vibration-absorbing device will likely be heard as an enhancement. Again, some applications will be more successful than others. If you try SDS or other recommended footers and you do not like the result, move them to another component until you identify and improve the actual, most offending component.

SDS primarily improves the focus by reducing vibrations. The supporting test results on the SDS website suggest that the effect is not quite uniform, being somewhat less effective in the lowest octaves. In practice, it was difficult for my ear/brain to notice this.

The SDS material seemed to have an effect that was pretty uniform across the board. With their longer wavelength, bass notes will never have the attack of the midrange or treble, but the bass did seem to tighten up along with the rest of the music as evidenced by the improved timbre in the bass region.  It is also important to recognize that the SDS squares will not "fix" your components. They are passive additions to your system, not actively altering the signal or changing the tonal balance.  Your solid-state amplifier will not suddenly sound like a tube amplifier and the tonal balance will not change. Your rig will still sound like your rig, only better, much as if you had just installed a dedicated line or a power conditioner, or a whole bunch of top quality footers… only better still. Improvement in focus is much like putting your prescription eyeglasses on and this is the principal strength of the SDS material. Improvements in transparency are more like taking your sunglasses off, and I noticed little change in this dimension. In my experience, changes in transparency, as defined, seem to fall principally in the domain of the active components of the rig and the signal carrying cables to a lesser degree.

I also compared the SDS squares with single layer squares of polished stainless steel and single layers of brushed aluminum, both of which improved the performance of the footers with which they were tested. But there was no placebo effect here — the SDS squares were obviously functioning at a higher level. And I use the word "placebo" here because there were times in the course of switching plates and footers when I would forget from one day to the next, exactly which plate was in use, thereby creating a blind listening situation. Usually I could tell the difference.

As I've said before, there is a system synergy that kicks in when everything in the system is treated in some way with vibration absorbing devices. I was hoping for enough SDS squares to treat my entire system. Fortunately, I have enough other footers in my arsenal to keep the system fully tweaked while using the available SDS squares on a variety of combinations of components. In every instance the improved focus and lowered noise floor led to enhanced perception of micro-dynamics, spatial cues and cognitive recognition of lyrics. Pace and rhythm were unquestionably accurate in the context of such fast attack and decay. This, in turn, led to greater emotional connection with the artistic interpretation or presentation of the musicians and the interplay among them. With recordings of live events especially, it was more like being there than the previous time I listened. I felt like I was a roadie at a Neil Young concert; that close to the man, himself.


Who's Next?

It is tempting to say that it doesn't get any better than this, but we know, someday, it will. Perhaps, as with razors, three blades of stainless steel will be better than two. Maybe, somewhere, there is a better polymer. I know this is true, because out of the blue, I received yet another batch of experimental footers that matched the SDS squares in audible excellence. This new material has vastly different composition and physical dimensions and it is suitable for somewhat different applications. It is also much further away in development from becoming a viable product. But then, neither are these 3" SDS squares an on-the-shelf product. Les had them specially cut up for me. In application, however, they were much more useful than the 420 x 275 mm (16.5 x 10.9 inches) black powder coated plate he sent along. The plate blocked ventilation holes and rode on the heads of screws on the bottom of virtually every component I had, compromising the effectiveness of the plate. As an interface between the flat bottom of a loudspeaker and the floor, or a speaker stand, I expect a custom sized (or something close) plate would be magnificent. My loudspeakers have special dedicated stands, so it was impractical to test this.

On more than one occasion I wondered how the SDS plate would improve any given loudspeaker if it were fastened to the bottom, or used on the baffles to mount the drivers…or even on the inside back wall to absorb the back wave. Why not use it on the mounting flanges of the drivers themselves or between the upper and lower cabinets of loudspeakers like the VR-4? How would it perform as a mount for a circuit board? Perhaps these would work well as a daughterboard for mounting tube sockets? Perhaps as a top deck of a tube amplifier for absorbing the vibrations of the transformers would yield excellent results? Or even as integral plates on speaker stands. The multitude of possibilities are intriguing, to say the least. And while some might suggest that my mind wanders beyond the boundary of reviewing, I respond with the creed that I am in this to enjoy the music and help others do the same.

Les told me that he would produce the smaller squares if there were a demand for them. I'd like to suggest that he offer a less expensive brushed aluminum version for use out of sight against the bottoms of components as I have done in this review. If they become scratched... so what? A more sturdy and puncture resistant version made from stainless steel like these prototypes could be used under the spikes of loudspeakers and equipment stands, powder coated black on one side and brushed stainless steel on the other to allow decorating flexibility. It is also enticing to imagine the small squares or strips being reasonably priced since they can be cut from scraps of larger commercial projects. Volume packaging might allow you to tweak your entire system at a discount price.



It should be pretty clear that I really love this stuff. I wish I had been able to test the stainless steel Isoplatmat on a variety of turntables, but the opportunity did not arise. Maybe I should take it with me to the Montreal show next year: "Say, would you mind playing that LP again with this turntable mat, please?"

The large plate was also less applicable to my components. Only with an inexpensive DVD player in the family room was I able to rest all four feet on it for modest improvements. It also made a slight improvement in the video when placed on top. It was the prototype squares that really showed me what the material could do. And from what I experienced, I hope Sound Dead Steel continues to develop this small plate concept and bring it to market. When used in combination with quality footers, it outperforms what any footer I've used can achieve on its own — by a significant margin.

For those audiophiles frustrated by the lack of money to buy top shelf components, SDS squares can become the great social equalizer, or at least tide you over until your kids are through college. On the other side of the same token, I hope other manufacturers will investigate this material for possible inclusion in their own components. If nobody gets greedy, the cost of really fine sounding equipment for live music performance, the recording industry and high-end audio could take a significant drop. The doors to enlightened music appreciation could open a little wider and the world will be a better place.

Thank you, Les.




Type: Vibration isolation/reduction system

The aluminum Isoplatmat is £68 without VAT ($128 + shipping)

Unpainted stainless option is £100 ($188 + shipping)

Sonphonon Steel HiFi Plates (all material is a sandwich construction)
Various sizes with pricing from £70 to £120

The 3" squares of Sonphonon reviewed here are prototypes.



Company Information

Sound Dead Steel Ltd.
190 Kingsway South
Team Valley, Gateshead
Tyne & Wear, NE11 0SH

Voice: +44 (0191) 482 1147
Fax: +44 (0191) 482 0582
E-mail: Les-sds@btconnect.com
Website: www.sounddeadsteel.com













































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