July 2018


The Hart Loudspeaker
Can this hybrid really deliver deep bass from a compact box? Paul Messenger finds out.
Review By Paul Messenger

  I seem to be fated to review unusual speakers. Every speaker that has come my way recently seems to have been a bit weird in one way or another. I've now had several based on a single full-range drive unit, and an active drive D'Appolito package. Then there are the cast iron Jerns, etc. etc. But none are quite as peculiar as this hybrid design from Hart Audio. It actually carries the name 'The Hart Loudspeaker', but to my knowledge it's by no means the first loudspeaker that this maker has developed.

In some ways it's very curious indeed. Its prime purpose is to deliver a full bandwidth sound, including very low (sub-40Hz) bass, from a compact speaker that's much smaller than one has any right to expect. The reason behind this is to try and find a speaker that is small enough to appeal to the whole family, but which also has the sort of bass delivery that will satisfy the true audiophile – a laudable ambition, for sure.

At £3890/pair such a combination doesn't come cheap, so one must apply rigorous standards to establish whether it really can deliver properly large scale from a compact box. At heart this is a modified Tannoy, starting out by packaging a 200mm (8 inch) Dual Concentric driver in a box that/s certainly compact, measuring just 24 x 39 x 19cms (WxHxD).

However, the modifications are considerable, as the back panel has no fewer than 11 tiny drive units, and these are driven by an internal amplifier fed power via a couple of wires that connect to an external power supply (a small 8cm x 4cm x 16cm box) that sits nearby on the floor, fed from an IEC socket.

Two small knobs on the front panel control the frequency and the level of the active drive. I chose to set these at maximum output and minimum frequency for best results under my conditions. I was also a little surprised when David Hart, during his last visit, drilled a couple of small holes in the front panels, effectively port-loading previously sealed-box enclosures.

Measurements
The measurements don't lie, and I have to admit I couldn't get this Hart speaker to match its claims of creating genuinely deep bass from a small enclosure. Although it does indeed deliver bass down to 20Hz, this is around 12dB below the 50Hz peak, and while I'm familiar enough with that peak, which is certainly partly a function of my room, larger speakers (such as the active-drive Blipo) don't necessarily show a similar discrepancy. I was also a trifle concerned by an audibly distorted sound that was created by feeding 20 to 50 Hz sinewaves.

Elsewhere the response could certainly be smoother, lacking some output 80 to 160 Hz, and subsequently showing some general unevenness. The in-room far-field response also dipped noticeably at a 2.3kHz crossover point, only partly recovering thereafter, so the treble overall is too restrained.

Sound Quality
Early on I converted the port-loaded enclosures back to sealed boxes by the simple expedient of blocking the ports, and although this didn't change the measurements much, I did feel that the sound as a whole was improved.

The sound as a whole was satisfactory much of the time, though it was mid-forward and somewhat restrained in the treble. However, when I dug out my Leftfield album, selecting Inspection (Check One) on side three in order to check out the bass performance, things did fall apart quite spectacularly. Any discrimination between the complex individual parts of the rhythms seemed to be lost, even though the overall sound balance seemed about right.

Conclusions
Even though I think the basic tenet of this loudspeaker has some merit, more work will be needed for it to become a practical proposition. I suspect that the samples that I'm reviewing may well be prototypes, and although the concept behind these speakers may have something going for it, more work is needed to turn them into a serious commercial prospect.

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Specifications
Type: Passive full range speaker with hybrid bass
Frequency Response: 20Hz to 20kHz (+/-3dB)
Impedance: 8 Ohm
Sensitivity: 94dB/W/m
Price:

Manufacturer
Hart Audio
Website: www.HartAudio.com