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Blue Horizon Professional Rack System

Blue Horizon Professional Rack System

It is truly remarkable how segmented the practice of hi‑fi has become. From the obsession with individual product reviews to the narrow assumption of silver bullet solutions, from the digital arms race to the one size fits all search for the ‘ultimate’ product, the focus frequently narrows beyond individual boxes to specific aspects of their design – first order crossover, diamond tweeter, Class A operation or some supposedly magic output tube or other device. Is it any wonder that designers become obsessed with singular aspects of their products to the neglect or exclusion of others?

But there are also those companies that spend their time looking out and looking around, gathering ideas and approaches, materials and technologies, often combining them to considerable effect. Not so much “Not Invented Here” as “Why reinvent the wheel when simply putting one of those rubber balloons around the outside would improve what we already have?” Blue Horizon is one such company, an umbrella brand that’s sister to the well-established Isotek Systems, with its extensive range of power products. Blue Horizon exists to fill gaps in the infrastructure and accessories market, but by far their most ambitious (and significant) product is the Professional Rack System. Equipment support has been a blossoming market of late, with the likes of Grand Prix Audio, SRA and HRS demonstrating the significant musical benefits to be had from properly engineered support systems. So much so that for many owners of serious high-end systems, racks have become one of the few easy-win upgrades, replacing basic solutions with superior supports often transforming system performance. But although the cost of a complete system support solution often pales into insignificance against the price of the kit it’s holding up, the kind of materials and technology employed by those heavily engineered equipment supports doesn’t come cheap. For those of us with less elastic budgets, even entry level models from the big-three support suppliers are out of reach, leaving us looking for more affordable alternatives that still tick most of the boxes – which is exactly where the Blue Horizon PRS comes in. On the face of it there’s nothing particularly novel or unusual in the design or execution. You can find most of these ideas incorporated into other racks. But the PRS is the only rack I’m aware of where you find all of these ideas incorporated into a single product.

In order to work properly, any equipment support needs to deal with energy reaching the equipment through the floor, through the air and finally, the energy generated by the equipment itself. All of these are important, but the very adoption of the misnomer, ‘equipment isolation racks’ indicates just how seriously that final category has been neglected. In practice, it’s not the equipment that we are trying to isolate, but the signal passing through it and that’s quite a different proposition. What the likes of Grand Prix Audio and HRS have so clearly identified is the significance of dissipating energy from within the chassis of the supported equipment. But that energy has to go somewhere – which is where the rack and supporting surfaces come in.

Any really sensible rack is going to offer modular, flat-pack construction, variable shelf spacing and expandable construction, so that it can grow with or adapt to changes in your system. Sensible choice of structure and materials will aid dissipation (and hence audio performance) while a weather eye trained on the market will keep things simple but upgradeable. The Blue Horizon PRS ticks all of those boxes and a few more besides.


Built around a screw together leg construction that’s similar to the popular Quadraspire racks, the PRS is about as straightforward and adaptable as they come. Short base legs with adjustable conical feet and a range of three different leg lengths (210mm/8”, 300mm/12” or 410mm/16”) provide enough spacing options without getting silly (and correspondingly expensive). Where the PRS scores is that the uprights are machined in one piece from solid stainless steel, a material whose resonant characteristics are definitely preferable to aluminium – just ask a cyclist! The execution counts too. The one-piece construction eliminates the mechanical discontinuities and practical challenges of the short lengths of threaded rod used by many manufacturers; the large diameter threads increase rigidity and stability. The slightly over-sized, knurled conical feet look pretty but also make adjustment a breeze, while the locking washers are equally easy and effective to use. Once levelled, locked and loaded the PRS stays that way.

Is there anybody left in the audio world that hasn’t tried the Ikea chopping boards as equipment supports? Apparently so, given how few of the racks on the market employ bamboo shelves – which is remarkable given the clearly audible musical benefits of the fibrous, mechanically disruptive but stable material. True to its “taking what works” philosophy, Blue Horizon has built its racks using the eco-friendly, carbon-positive material. The PRS shelves are 30mm thick, square edged and available in natural bamboo and black or white lacquer finishes. Like all such bamboo board, the sheets are built from thin strips, layered and laminated together, which offers yet another random aspect to the supporting structure and spaces its performance still further from the monolithic nature and single, thuddy resonance of MDF. But here too, execution is key. Shelves are available in single and double width versions, with the legs available in packs of four or six to suit. The two shelf widths can be combined into a single, composite rack or even an extended, multi-bay construction; so far so good; in fact – so far, so very good indeed. Blue Horizon even supply a trio of bamboo couplers with each support level, to sit between your equipment and the supporting shelf, perfect for bypassing those ‘isolation feet’ that are fitted to most electronics. Bamboo blocks might not be the last word when it comes to equipment couplers but Blue Horizon including them gives you another lift in performance and they’ll certainly serve until you can afford something better from HRS, Stillpoints, Grand Prix or Neodio.

Blue Horizon supply the base legs with standard brass footers, but also offer their optional Mk2 Spike Shoes machined stainless steel which is loaded with resonance deadening compound. If you are using the PRS rack on a hard or polished floor, these provide a more sophisticated and effective interface solution. Seriously? Believe me, swap out the standard footers for the Mk2 Spike shoes and you won’t be going back. A three-layer construct involving a steel body, internally damped with the company’s proprietary RDC resin-based composite and finished with a cork layer, these a-resonant discs offer a substantial increase in sound quality despite their modest (£80/4) price. I’ll describe their sonic benefits later, but suffice to say, I’d consider them an essential part of a properly constituted PRS solution.

Sensible choice of materials, excellent execution and carefully considered options add up to a rack that ticks not just the common sense boxes but also meets an awful lot of my own personal demands, requirements that have been arrived at after years of painstaking experimentation with varying support solutions and combinations. When it comes to racks I’m pretty sure what I like and I like the PRS’s choices a lot. It even succeeds where so many racks fail, actually looking better when it’s full of equipment than when it’s empty.

So what don’t I like about the PRS? Blue Horizon supply optional self-adhesive felt washers that you can place between the shelves and the uprights to protect the painted/bamboo surfaces. Don’t use them! They are sonically disastrous, robbing the rack of dynamic range, focus and transparency. Indeed, if you have an existing rack (where the felt was pre-installed) it’s well worth taking it apart and removing the offending material. Still, kudos to Blue Horizon for finally making the washers an option: given my druthers I’d eliminate them completely. My other pet gripe is the bent-metal tuning forks that are screwed to the rear of each shelf. Yes, really… Masquerading as a cable management solution, these aluminium plate ‘coat-hangers’ are recessed into small rectangular cut outs in the rear of each shelf. Leaving aside the practical issues with the arrangement and whether or not physically restraining your cables in close proximity like this is a good idea (it’s not) just ping one of the aluminum retaining plates with a finger to hear it sing! A nod in the direction of housekeeping as opposed to performance, they have no place in a serious set-up. Once again, the good news is that they are easily (and best) removed.

In use, the PRS rack has proved a God-send. The unit is astonishingly rigid for a screw-together structure, partly because it’s possible to get the legs and shelves really firmly clamped together. That, the height of the tallest uprights and the sensibly proportioned shelves has allowed it to be easily adapted to accommodate a whole host of different equipment. I change equipment and systems far more frequently than most members of the public, but I’m sure that the benefits of this rack’s versatility aren’t lost on end-users. The PRS has delivered consistently superior sonic results to my alternative, modestly priced rack solutions (Hutter Racktime and Quadraspire). However, there are a few specific steps to be taken if you are intent on getting the best from this product…

Let’s start with a simple rack. The stock PRS bamboo rack has a stable musical clarity that gives an impressive sense of space and musical separation. Compared to my stock alternatives, the basic PRS rack delivered a nicely spaced soundfield, with solidly rendered instruments and an impressive sense of presence and body. With plenty of energy and drive, there was no danger of the music lagging. That focussed energy and musical momentum comes to the fore with the hard coupled construction. Fit the felt washers and things lose that clarity and focus when it comes to musical lines and exchanges, dynamics and attack.


It’s also time to insert the Mk2 Spike Shoes. You are probably not expecting much, but it soon becomes obvious that the benefits of this simple upgrade are substantial. The first thing you’ll hear is the expanded range of harmonic colour and the extra shape there is to notes. Listen longer and you’ll come to realize just how much air and depth are added to the soundstage. Play the Kertesz New World [Decca 478 2826] and the spatial, harmonic and dynamic benefits are immediately obvious, from the studied pacing of the unmistakable opening passages, to the timpani detonations that underpin the first crescendo. Why the disproportionate improvement? Because the spike shoes govern the rack’s interface with the outside world and, in turn that means they impact on every component supported in the rack: one-set of spike shoes will improve the performance of your whole system. There’s also nothing stopping you using them under speakers/stands although here you’ll want to take care to compensate for their physical depth – otherwise you’ll likely be lifting your speakers away from their floor reinforcement. Just compare the height of the speaker on its original footers and with the Mk2 Spike Shoes in place and adjust the spikes accordingly – assuming of course that you’ve really nailed your speaker set up in the first place. If not, here’s the perfect excuse to revisit this critical issue…

Blue Horizon correctly suggests that the basic rack is just a starting point. Their strategy is to first add additional isolation platforms to the support levels and then to split the levels into a stackable solution, with levelling cones between each shelf, creating a good, better, best progression. I tried this approach and while the Sanctum isolation platforms work in the context of MDF shelving, that pairing is outperformed by a single bamboo shelf and it certainly makes no sense to me to place a slab of isolated MDF on a bamboo supporting surface. So, having discarded that option, instead I opted to add an additional short layer to the base of the rack – effectively standing the rack on an amp-stand. Even I was surprised by just how successful this was. The increase in dimensionality, transparency and immediacy was remarkable and would have been reward enough, but on top of that, the increase in musical fluidity and articulation was astonishing. Performances became far more lucid and purposeful, taking on a natural shape and sense of proportion, with the Kertesz disc – as well as Morphine and a little Vampire Weekend – confirmed that the bigger and more demanding the piece, the bigger and more demanding the system, the more apparent the rack’s benefits become.

For me, the standard PRS rack with its bamboo shelves (and couplers) combined with the Mk2 Spike Shoes is definitely good. Adding a decoupled level to the base is definitely better, but best of all, it opens the way to using more sophisticated couplers sitting between your electronics and the shelves to really release your system’s musical potential. If you are still subsisting on your first or even an inherited audio rack, do yourself a favour. You underestimate the musical importance of system support at your peril and, whether you are looking for the starting point when it comes to serious system support or it’s high-time you got round to properly supporting a serious system then the Blue Horizon PRS sets the benchmark. Pretty, effective, adaptable and upgradeable, this is the point at which audio support solutions become more than just furniture.


  • Type: Modular equipment support
  • Shelf Material: Bamboo
  • Uprights: Solid stainless steel
    210mm/8”, 300mm/12” or 410mm/16”
  • Footprint: 600 x 450 or 1140 x 450mm
  • Shelf Finishes: Natural bamboo, black or white gloss
  • Prices: From £1,459
  • Mk2 Spike Shoes: £79.95

Manufacturer: Blue Horizon


URL: bluehorizonideas.com 



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