The Hart EVO-1 is a substantial speaker system that consists of two cabinets per channel, stacked one upon the other. One box contains eight bass drivers and is designed so that these drivers face the wall. The other cabinet features a 300mm dual concentric drive unit built around a Tannoy chassis. Hart has modified it and fitted a different magnet, so it’s no longer the same beast, but it’s an expensive piece of hardware nonetheless. On the back of this head unit box is an active amplification module, which drives the eight units in the bass cabinet.
These ‘bass’ drivers are only 115mm across, so are normally something that only makers of sound-docks would describe as a bass unit. But get enough of them together and stick a 500 watt amplifier on the end and they deliver bass that is faster, cleaner and deeper than pretty well any passive speaker on the market and quite a few active ones at that.
David calculates that these eight drivers are equivalent in area to a 330mm cone but the combined magnet power is equal to a 300mm magnet, something that would only work effectively on a 450mm driver.
The amplifier module looks like something from a sophisticated subwoofer, it has inputs for a high level signal and it has both XLR and RCA phono inputs for a low level signal such as is usually used in ‘point one’ systems. Hart recommends the high level route ? this way you have the same character of signal going to both halves of the speaker, and it also makes the amp module’s job easier. The amp module has controls for phase, frequency contour, high level and low level gain all of which have solid wood knobs to match the speaker’s finish.
The veneer on the sample I had was a superb book-matched walnut burr with beautiful figuring, Hart offers a number of stunning veneers which are laid up by a local company. Stainless cups for the rubber ball cabinet separators offset this finish. These balls started off as large bearings but have become very hard rubber spheres because of the damping that this approach affords. Remarkably these balls can survive the 62kg mass of the top cabinet and still retain their shape. They are also used between the bass cabinet and the 10mm steel plinth that forms a base for the system. This pair has the upgraded wire, crossover, coaxial driver and voice coil, bass amps, and connecting cables. This speaker is so transparent it is like an electrostat with body and dynamics.It is 97 db efficient at 8 ohms but can take incredible power without breakup.