I have never heard a bad ProAc speaker, and over the years, I have enjoyed them in many systems in many listening rooms. The K1 is the smallest of the K range, where the prefix refers to the Kevlar bass/mid drivers found in all models. The relatively recent K1 is the only stand-mount and follows a classic and traditional design model, proving itself over the years. The final success of the design always comes down to the implementation of the elements. Cabinet, drivers, crossover and stand, in equal order of importance. Get it right, and you can have a giant killer on your hands. I have heard so many systems that included various three or even four-way floorstanders that, in my opinion, would have been far more enjoyable if a high-quality two-way stand-mount replaced them. It seems that the promise of copious amounts of bass is just too hard to resist because a manufacturer told me recently that their market research informs them that floorstanders are what the audio buying public want.
But let’s start with what supports the K1 by looking at the high-mass stands themselves because one should never underestimate their, ahem, massive influence on what you hear from the finished installation. These come in a modular form and require assembly. A ringing bass plate with spike options and a more solid piece of steel beneath the speakers are separated by three wide diameter black tubular legs, with the possibility of filling them with sand. A solid aluminium post at the front of the speaker looks good and continues the design theme of the built-in plinth. These stands are an optional extra but, looking around, you’ll be lucky to find such a convenient fit elsewhere because the K1 is quite deep. Assembling them with a mixture of bolts is straightforward, and the black large-section supports tend to fade into the background because the bright, silvery front pillar takes the eye. Overall, they do the job, but I can’t help but think that they could have been more elegant and perhaps more minimal. Also, both the review speakers rocked very, very slightly on the flat top plate, so you need four tiny bits of Blu-tac to take up that slack. The spike fittings are up to the job, but I had the most success with a quartet of Stillpoints between wooden floor and base, and if I owned a pair of these loudspeakers, I might even think about damping the bottom with some stick-on pads.
The speakers themselves are immaculate, though the base might be better in a less ‘naked’ form. The review models were finished in Tamo Ash, a beautiful and highly figured light coloured wood, not unlike curly maple, with impeccably matched veneers. The cabinets themselves are formed from panels of HDF (high-density fibreboard), Bitumen-damped internally and of varying thicknesses. The first thing you will notice is the unusual built-in plinth which curves through an elegant arc at the rear of the cabinet to a 50mm space that is propped at the front by the same aluminium post material that fronts the stand. Visually it joins the stand to the cabinet, and that continuity is lovely and further detracts from the three bigger and uglier rear supports, as I mentioned earlier. Far from being just an aesthetic element, though, this is one of the K1’s main technical design features because the loading for the bass unit exits here in the shape of a hidden port. It seems to me that designer Stewart Tyler has been clever here in firing it downwards and fixing a boundary distance within the port’s influence. This port makes the K1’s behaviour more predictable and should give the user more latitude when finding their final listening positions. With a fair-sized cabinet such as this and a powerful Kevlar bass/mid driver crossing over at just above 3 kHz, I can see that a rear-facing port, though far easier to implement, could prove troublesome if you need to site the speakers close to a rear wall. In this configuration, it works superbly, and I couldn’t hear the port at all.
In a hotly contested market area, the K1 brings some serious driver armament to the table. A Kevlar 165mm (6.5 inch) bass/mid driver and a ProAc ribbon tweeter with an Alnico magnet that sits in its enclosure and features a diaphragm “As light as a human hair”, according to the literature, which is truly remarkable when you hear how it performs. A few years ago, Kevlar-coned drivers gained a reputation for harshness, but I could detect none after some bedding-in. We have a very, very stiff cone that is exceptionally responsive, can start and stop with impressive control, and is also nicely accurate pitch-wise and, when in the company of this admirable tweeter, very textural too. The midband is a real stand-out on the K1, as I’ll discuss later.