Tannoy System 600

Tannoy's latest nearfields offer an updated version of their famous dual‑concentric technology, while still retaining that distinctive Tannoy sound. Paul White test drives them.

While virtually every other loudspeaker manufacturer on the planet has settled for physically separate woofers, tweeters, and occasionally mid‑range drivers, Tannoy have exhibited considerable tenacity in adhering to their original dual‑concentric concept. For those unfamiliar with dual‑concentric loudspeakers, the design is characterised by a horn‑loaded tweeter mounted at the centre of the bass/mid driver. To improve the efficiency of the horn design, the bass/mid cone acts as an extension to the tweeter's own short horn. As with all the latest generation of Tannoy dual‑concentric speakers, the tweeter incorporates an acoustic waveguide between the pressure transducer and the outside world, to force the tweeter into generating a spherical wavefront — the idea being to better control the directivity of the tweeter.

Dual To The Death

Obviously, Tannoy haven't stuck with the dual‑concentric principle out of blind intransigence: there are a number of well‑documented benefits to this approach, the most important of which is that the speaker behaves as a point source of sound, ensuring that the high‑ and low‑frequency components of the sound always arrive with the correct relative phase to each other, regardless of whether the listener is on or off axis. For nearfield use, this also means that the speakers can be used on their sides without compromising their performance. Furthermore, horn loudspeakers are more efficient than direct radiators, so a horn tweeter is able to produce more acoustic energy for the same input power.

Inevitably, every engineering approach has its disadvantages as well as its benefits, and in the case of dual‑concentric speakers, the larger you make the speaker, the harder it is to make the woofer and tweeter frequency responses meet smoothly — and there's nowhere to put a mid‑range driver. What's more, horn‑loaded loudspeakers can suffer from phase problems caused by reflections and air non‑linearities occurring inside the throat, resulting in a rather harsh edge to the sound, though even these can be minimised by careful design.

System 600 Design

The System 600s utilise a 6.5‑inch driver, which is small enough to enable the woofer and tweeter elements to match up smoothly. The 'tulip' waveguide can be clearly seen at the centre, and the injection‑moulded polypropylene cone is suspended in a high‑compliance, nitrile‑rubber surround.

Judged as nearfield monitors, the System 600s present a good overall balance of sounds, with the proviso that there's no really deep bass.

The HF diaphragm is fabricated from aluminium and magnesium alloy to give it sufficient rigidity to work as a true piston to 25kHz. This is suspended in an inert, nitrile‑rubber mounting with a very narrow roll surround to reduce resonance effects to a bare minimum. The tweeter voice coil is copper, chemically bonded to a Kapton former, and ferrofluid is used in the magnetic gap to aid cooling. A low compression ratio ensures minimal distortion from air compression effects, and the crossover frequency is at 1.8kHz. Apparently, a low‑order crossover is used to ensure a smooth transition between the low LF and HF ranges, and because the drivers behave as a point source, the problems normally associated with overlapping frequency bands are much reduced. The shape of the LF cone profile continues the horn flare of the tweeter, and trim rings are used at the outer edge of the drive unit to help create a smooth transition from the horn flare to the flat baffle.

The vinyl‑coated MDF cabinet design is visually attractive and very solidly engineered — as you'd expect from Tannoy's highly advanced cabinet manufacturing plant. As well as looking distinctive, the cabinet shape also makes it very rigid, which helps counteract excessive cabinet vibrations. Chamfered corners are used to reduce cabinet edge diffraction, and the twin reflex ports are filled with acoustic foam to fine‑tune the cabinet damping.

The sum of all these parts is a passive, 2‑way monitor weighing in at 7.5kg and measuring just 220 x 360 x 267mm. A single pair of terminals provides for bare wires, banana plug, or spade terminal connection, and nominal impedance is 8Ω, with a quoted sensitivity of 90dB for 1W at 1 metre. As far as power goes, the speakers are rated at 80W RMS average, or 160W RMS programme material. In practice, a good 100W (into 8Ω) amplifier seems just about right for them.

The rated frequency response of the System 600s extends from 52Hz to 20kHz, and judging by the curves, this is relatively flat within two or three dB either way, with the inevitable roll‑off at either extreme. Distortion is quoted as being better than 0.8%, but as the conditions under which this may be measured were not provided, it doesn't mean very much. Dispersion is a creditable 90 degrees to the ‑6dB point.

Testing Testing

Judged as nearfield monitors, the System 600s present a good overall balance of sounds, with the proviso that there's no really deep bass, and such bass as there is sounds just a hint 'tubby' or constricted. This isn't unusual given the small physical size of these speakers, and in a home studio environment or traditional nearfield application, the bass extension is generally adequate. Removing the foam plugs from the bass ports brings about a slight improvement in the bass end and also seems to open up the overall sound a little.

A good test of monitors is to listen carefully to the vocals on songs that you know are well recorded — and finding a well‑recorded song isn't always the simple task it ought to be. Here the System 600s behave quite well, with just a bare hint of edginess in the 3‑4kHz area of the spectrum. Once again, this isn't serious, and the mid‑range sounds a good deal more open and better defined than it did on some of the older generations of Tannoy monitor.

When the System 600s are presented with a complex mix, the slight edginess noticed on vocals becomes a little more pronounced, though to maintain some perspective, there are far worse behaved monitors in higher price brackets. Perhaps more serious is that complex mixes start to sound a little confused in the mid range, though the imaging remains better than average. At the top end, cymbals, snare drums and picked guitars are bright and detailed with only a hint of 'splashiness'.

Verdict

Every pair of speakers ever built is a compromise, and the System 600s neatly avoid the worst of the old‑fashioned, rather coloured Tannoy sound. Their strength remains in their stereo imaging and wide angle of dispersion, both of which are excellent. However, I'm not entirely convinced that the mid‑range problems associated with dual‑concentric speakers have been entirely eliminated, though the colorations are subtle, and most people will very quickly get used to them. Those with a history of working with Tannoy monitors will probably welcome the System 600s as an improvement on a classic design.

Given their price, these monitors perform pretty well in a nearfield context, and they have the benefit that they can be used 'landscape' rather than 'portrait' without compromising their excellent dispersion. They're also extremely well built. Having said that, there are an awful lot of conventional two‑way systems out there competing for your money, and to my ears, some of these sound more transparent than the System 600s, and/or have a greater bass extension. Ultimately, if you're a Tannoy person, you're sure to like the 600s, but if you're not entirely sure, audition them alongside a selection of their competitors and hear for yourself how they compare.