The harsh reality is that, in seeking to isolate your components from mechanical energy transmitted through the floor, you – and by extension, your rack – are only addressing half the problem and, the least important half at that. It’s the functional equivalent of an audio upside down cake!
In order to isolate the signal, the supporting surfaces must isolate it not only from external energy travelling through the floor, but drain airborne and self-generated energy from the component chassis it passes through. In other words, the rack sits in a sandwich, with the floor below it and the equipment on it. To optimise system performance, it needs to deal with energy travelling up from the floor and down from the equipment. Suddenly you are looking at a whole different problem…
Given that energy is going to enter the rack structure, that structure needs to dissipate it – whether that energy is travelling up or down. Once you start using separate supporting platforms for each component, that platform becomes solely responsible for dealing with the critical, internally generated and airborne energy contained by the component’s chassis – rather than having access to the entire, dispersive possibilities of the structure as a whole, as well as its mechanical ground path. In turn, in order to be effective, that tends to make those supporting platforms large, complex and expensive: just look at the SRA or HRS price-lists for the evidence of that. As racks and platforms extend their ambitions, prices for complete systems end up increasing dramatically.
But functionally speaking, this isn’t solely a rack issue. Those soft rubber feet that equipment manufacturers so love to put on the products are equally culpable. What’s required is a hard coupling between the chassis and its supporting surface. Nor are all rack manufacturers oblivious to this issue. HRS offers both its Nimbus/Vortex/Helix couplers and its Chassis Damping Plates – collectively designed to deal with exactly this problem. Despite appearances and the use of a polymer interface (or two) these are sophisticated, frequency tuned coupling solutions that work brilliantly. But you can’t make people use them. How many HRS racks have you seen in systems or at shows? How many of them used the coupling system to maximise performance? Yet the benefit of these couplers and chassis dampers is easily demonstrated. So much so that I would recommend investing in them before an HRS (or other expensive) rack, rather than as an afterthought. But to me, what is just as interesting is that increasingly, the HRS platforms that sit in their frames are being sold with solid rather than decoupled feet. That’s a big step towards a homogenous structure. Time then to look at what sort of homogenous structure we should be aiming for…
One size fits all?
I’ve just spent quite a lot of time discussing HRS products, their use and frequent misuse. That’s almost inevitable given the extent to which HRS dominates the high-end rack market. Not only are their products seemingly ubiquitous, but they offer an almost prototypical (or much imitated?) structure. In criticising them, I’m not singling out HRS and I don’t have a down on the company. Far from it. I use their RSR rack and various platforms, while their couplers and damping plates are a permanent part of my system set-up approach. It’s just that as the most recognisable and familiar product, they represent the benchmark – and therefore, they’re there to be shot at. Just bear in mind that although I’m tending to draw examples from the HRS line, products from other brands are just as, if not more, culpable. Thankfully, Mike Latvis from HRS has broad shoulders…
