There’s different for the sake of it, different for a reason and then there’s different with attitude. At first take it’s easy to place Zu Audio and their products firmly in the third category; after all, they do come from Utah. Not that there’s anything wrong with Utah, it just also happens to be the home of Wilson Audio, a pretty daunting neighbour if you happen to manufacture loudspeakers. But experience and a little sober reflection will soon have you revising that opinion. The Zu Definitions are distinctly different, but there’s plenty of cool, collected reasoning behind that difference.
Of course, even the paper spec tells you that this is no ordinary speaker. Zu’s claim of 101dB efficiency should attract your notice (although in around 95dB seems to be about right, calculated in the conventional way). But it’s the two large cones that decorate its upper half that standout, theoretically and visually. These are the same Zu260FR-G2 units that grace the company’s slim, monolithic looking Druid IV design reviewed by PM in Issue 45. Proprietary, high efficiency, wide bandwidth designs they are built onto a high-quality commercial basket and magnet assembly. But the paper cone(s), surround, voice-coil and central phase plug are all specified and assembled by Zu. Direct connected to the amplifier, without any form of crossover to get in the way, they form the heart of all Zu’s designs, running flat(ish) from around 40Hz to about 12kHz before finally tailing off. Of course, the trick with any such “single driver” design is to get as much bandwidth as you can without crippling the potential benefits when it comes to temporal and dynamic coherence and immediacy. Which is exactly where most of the real purists come unstuck. Push things too far and you end up with horrific frequency response aberrations and colouration to match. It seems strange to use the term conservative when it comes to Zu, but that’s exactly what these speakers are, in engineering terms at least.
Of course, 40Hz to 12k contains the vast majority of musical information, information that arrives via that single, directly driven driver. The result is a sense of tactile immediacy, an almost infectious impulse to conduct, sing and even dance along with the band. The undulating bass lines that underpin early The Cure take on a living, breathing momentum, the slashing contrast of the sparse guitar riffs thrilling in their perfectly pitched and placed precision. They may seem slap dash and chaotic: the Definitions let you hear just how precisely the tracks are really crafted, but without robbing them of their essential pace and energy. This is what music is about; it’s what good hi-fi is about and it’s definitely what the Zu speakers are about. That they do it so successfully is down to the clever way in which the benefits of those broadband drivers are maximised and supported.