REVIEW CONDUCTED ON STANDARD UNIMPROVED DUAL MONITOR
by Jason Kennedy
You meet some interesting characters in the hi-fi fraternity and David Hart qualifies as one of them. How many people do you know that gave up a career as a barrister to follow their dream and build a no-holds barred loudspeaker? Perhaps that is why he spent four years coming up with a loudspeaker that incorporates some pretty radical thinking.
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 Р 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.
The bass system is designed to work into the corners of the room and use them as a crude horn, thus you need to angle the tower so that the eight drivers are firing in that general direction. I preferred the balance of the mid and treble with the speakers set square to the wall but that does undermine absolute extension or at least it seems that way. The quality of bass that this speaker delivers is so clean and articulate that you don’t get the same degree of room excitement as is normal, as if room modes are not being set off to the same extent as is usually the case with big speakers. It has phenomenal speed, which means that bass instruments come through with the subtlety and definition we associate with those pitched higher up the scale. This makes for awesome groove factor on anything with rhythm, be it Steely Dan’s ‘Bodhisattva’ or Mofro’s "Blackwater".
I tried a variety of amplifiers with the Harts and each made its mark, not least the Digital Do Main B-1a with its VFET output stage. This radical Japanese amp loved the high sensitivity on offer and rewarded me with some of the finest and most atmospheric results encountered in a long time. John Abercrombie’s gentle Wait Till You See Her ECM album can sound a little bland with less revealing systems, but here both the tune and the presence of the musicians is placed front and centre. The realism is spine tingling, and this is not merely because of the bass system of course, that coaxial driver works phenomenally well as a mid/treble system despite its size. So well in fact that noise levels seem lower than usual This could be because of the sensitivity on offer but in many ways that should have the opposite effect and reveal any hash at the bottom of the amp’s output range, but with something as refined as the Digital Do Main that doesn’t seem to be the case.
Credit should also go to the Resolution Audio Opus 21 CD playing source; via the DDM and Hart the older and notably multibit player is the source of choice. After using the system for a while David Hart told me that at home he uses the boxes the other way around Р with the bass system on top and the base plate sitting on its front spikes only so that the main driver faces upwards. This he says works better for vinyl and I was going to give it a go until I discovered how hard it was to lift the main driver/amp pack cabinet.
Moving over to the Quad II Classic amplifier proved that despite the active bass drive the low frequency performance of the amp has a clear influence over this end of the spectrum. Now the bass was richer and softer but with plenty of energy if not so much power or snap. The overall result was attractively easy to enjoy but full of detail and, if not as sharp edged as the solid state alternative definitely more natural, double bass coming through in woody and timbrally rich form. The system also seemed to untangle the densest compositions and reveal the inner beauty of the music rather better, it had a more positive and optimistic view that brought out the message in the material rather effectively.
Moving over to my reference amp, the Gamut D200 MkIII brought back a high degree of analysis to the speaker, the way that a vocal has been treated is laid bare in a completely clean fashion. Often highly analytical systems can be a bit on the incisive side for my tastes but so long as the main drivers aren’t pointing straight at your ears this isn’t the case here. Of course if you want a sharper sound then the speaker can be set up to deliver it, likewise the bass can be adjusted to suit the room with the controls on the amp pack. The key ones are phase and roll-off both of which can be tuned quite easily, especially if there are two of you to do the job.
Back with the music Arab Strap’s vocal is almost laser cut because clarity and presence are so strong, then the drums come in and their reverb stretches way off into the distance. All of which makes for very powerful and engaging listening with material that’s as intense and intimate as that album provides.
Around this point in the proceedings I spent an evening listening to JBL’s new K2 horns at a friend’s house, he was raving about the detail coming out of these megabucks speakers and it wasn’t hard to hear why, however returning to the Harts and playing the same tracks resulted in a very similar level of detail with more powerful and substantial bass. Clearly the active element played a part here but there’s no getting away from the transparency on offer across the band.
Putting another amp into the mix, Chord’s compact Cyan Click revealed just how sensitive the speaker is. The Chord’s level indicator didn’t get out of the teens whereas with my B&W 802s some tracks warrant an output of twice that. By rolling the main driver off at around 70Hz and taking bass drive out of the equation, Hart has delivered a true high sensitivity speaker without the difficulties inherent with horn systems Р no wonder the Quad amp sounded so sweet.
When David came to take his speakers away I was very sorry to see them go, the EVO-1s are extremely revealing and engaging speakers that revel in a high quality signal. They are clearly more than worth the asking price even if the aesthetics are a little challenging. This would not be such an issue in a larger and lighter room than mine perhaps but if there is any justice it’s the only thing that should stand between them and world domination!
SPECS & PRICING
System: 3-way active bass
Mid/treble: 300mm paper dual concentric with compression tweeter
Bass driver: 115mm polypropylene cone (x8)
Bass amplification: 500 watts
Bass controls: phase, frequency contour, high & low level gain
Impedance: 8 ohms
Dimensions HxWxD: 125x44x44cm
Weight: head unit 62kg, ABM 38kg, plinth 22kg
Finishes: maple, walnut, vavona burr, eucalyptus, lacewood