If you read my Frankfurt show report in Issue 2, you'll know that I was impressed by a whole range of products manufactured by Clearlight Audio in Germany from a proprietary material, RDC. This is a resin based compound which contains grains of numerous different materials, stretching from lead on the one extreme to rubber on the other. The intention is to create a random structure incapable of sustaining resonance, and thus able to pass energy in an extremely linear fashion.

The applications for such a material within hi-fi engineering are legion, and already Thorens and Loricraft amongst others are employing precision RDC castings in their products. But while Clearlight wait for the rest of the world to cotton on, they have created a range of support products, and I've managed to lay my sticky fingers on some.

What we are talking here is cones or feet, and platforms/shelves. I started out with an Arcam Alpha 9 sat on a RoomTunes DeLuxe Justarack, mainly because the 9 is notoriously finicky about its supporting surface. The first products I tried were the small cones, the RDP feet and the SPP platform. The results were as follows:

RDC 2 Cones (27mm high, 30mm diameter) £25 / 4
Slipping three cones under the Alpha 9 had a profound effect on its performance. Listening to the title track fromA Few Small Repairs (Columbia 484327 2), the whole soundstage became more focused and stable. The guitars had more attack and body the drums more power, depth and texture. But it was the voice that really did it. Far more real, the breathing a totally natural part of the performance, the vocals suddenly became warmer and more solid, yet at the same time more detailed and intimate. Drive and attack both improved, no doubt helped by the increase in instrumental presence.

The differences were consistent across a whole variety of discs and musical genres. Large scale classical pieces in particular, benefited from the organisation that the cones brought to the 9's prodigious detail retrieval capabilities.

RDP Feet £42.50 / 4
These are not strictly an RDC product, more of a spin off. They consist of a small cylindrical foot, supported by a net which is stretched over a ribbed ring. Energy fed into the foot travels down the net's fibres which are held in tension against the convex ribs, rather like a guitar string against a fret. The uneven spacing of the ribs allows the energy to disperse across a range of frequencies, translated to heat. The overall result is perhaps best understood as akin to what happens when a person jumps into a blanket held by Firemen. In this case the ridges and fibres take the absorbative role of the firemen's arms. Putting the feet under the nine produced better separation and a warmer tonal balance, and perhaps a slight gain in overall detail. The result was rather like Sorbothane, but without the softness and rounding that goes with that material. Better, but not as good as the cones.

SPP Platform (425mm x 330mm) £96.50
Finally I tried the SPP platform. This is basically an MDF shelf which has had a spiral groove cut from its underside, into which fits a moulded snail of RDC. The whole thing is supported on RDC 2 cones, screwed onto M8 posts. The idea is to create a structure which will dissipate standing waves, feeding the energy down the cones.

In use the results are similar to the RDC 2's, but with better separation and a blacker background to the music. The platform drops the noise floor to a point where the instruments hang in an inky black space, further adding to the attack and dynamic improvements generated by the cones.

Clearly these improvements are far from subtle and particularly given the modest cost of the RDC 2 cones, exceptionally cost effective. The RDP feet are a definite alternative to the cones, and I can see situations where they might be the preferred option. However, given a well balanced system, the cones are going to win out most of the time. The shelf is also excellent, although necessarily more expensive. Whilst it will justify its price as a platform, I suspect that where it really comes into its own is as a replacement shelf (UK£58) in an existing rack, where the glass or MDF boards supplied will undo much of the good work done by the cones. Clearlight already manufacture shelves sized specifically to suit the more popular racks on the market.

Fascinated by these results, I slipped four of the large RDC 1 (335) cones under the rather promising valve pre-amp that's sitting in the system at present. It's already standing on a Townshend Seismic Stand, so it's well isolated from the outside world, therefore any benefits would be in evacuating internal energy. This the cones proceeded to do with aplomb. I really wasn't prepared for the dramatic improvement in the rhythmic integrity and sheer get up and go that the cones wrought on the music. Removing them left the beat blurred and tempo lacking tension. The big RDC 1's are really aimed at speakers rather than equipment, but I haven't had a chance to try them in that role yet. What is interesting is that if you look at the system review with the Townshend Seismic Speaker Supports, the Shahinian Starters with no spikes at all, and the Audioplan Kontrast IIIi's with their Anti-Spikes, it's becoming clear that an increasing number of people are beginning to question the accepted wisdom of direct coupling speakers to the floor using sharpened steel.

I am writing this as the copy date passes, so further experimentation (including comparisons with the Nordost Pulsar Points) will have to wait. In the meantime RDC has made a stunning debut, more than rewarding my interest.

For further information contact:
Loricraft
Tel. (44)(0) 1672-511401

Clearlight Audio
Tel. (49)(0) 781-970-9991
Fax. (49)(0) 781-970-9993

Postscript
I just couldn't let this one lie, so risking a severe battering about the bonce from my editor's hat, I fearlessly pushed on into that twilight zone beyond the deadline. Well, actually I took a couple of sets of cones down to Phonography in order to try them under a few different bits of kit, not least the aforementioned Shahinian speakers.

We started with a Naim CDX/XPS, 82, 180, Obelisk set-up. After demonstrating the benefits of manual over remote operation (See the "Its illogical" article, this issue - Issue 3) to general bemusement, we moved onto the RDC cones, starting with three RDC 2's under the CDX. The results were just as expected: greater clarity more information better integrated, faster attack, clearer decay. Very worthwhile, with vocals in particular becoming obviously more natural, both tonally and in terms of pace and expression.

Next, it was time to tackle the speakers. Unfortunately the RDC 1's weren't tall enough to by-pass the Obelisks' casters (!), so we wheeled in a pair of Arcs instead. Now, I am an acknowledged fan of the Shahinians, but the Arc is my least favourite model. I'm tempted to point a finger at its MDF cabinet (the others all use ply), but it has always sounded rather thick and sluggish to me. Sure enough, replacing the Obelisks was a salutary experience. The music definitely thickened up, and the sound stage became opaque. The vocals took on a chesty deeper tone, and the pace slowed.

Slipping four RDC 1's under each corner of the Arcs lifted them off their nylon(?) feet. (Experiments with three cones were unsuccessful.) Suddenly the heaviness was gone. The sound-stage opened out and instrumental definition and attack was dramatically improved. The voices soared clear of the murk, full of vitality and life. The greater attack and clarity meant greater rhythmic integrity as leading edges improved right across the frequency range. Drums took on a sense of volume and texture which had been entirely lacking. They actually started to sound like a tuned instrument! In case you are still in any doubt, these changes are not subtle. They change both the quality and character of the Arc, moving it far closer to the Obelisk, and offering much greater musical insight without compromising the coherence which is a Shahinian hallmark. Would the cones be as effective under the ply-bodied models? That really will have to wait for another day but rest assured, I will be finding out.

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