Why are most loudspeakers still rectangular boxes? The box is there mainly to stop energy from the rear of the drive units reaching your ears and messing up the stuff you're meant to hear; the shape of the box is generally to do with simplicity of manufacture.
However, boxes have internal reflections, which can make them sound, well, boxy. That's why every manufacturer has its own take on the shaping of the box, or its inner walls, or the application of damping materials. Sealed boxes can also swallow bass.
That explains the use of everything from simple front-venting ports to complex folded transmission lines inside cabinets to extract better low-end extension.
Cabinet reshuffle
For the Reference R909, Jamo's engineers have done away with the cabinet completely: there's just a tall, wide baffle, beautifully finished in a range of colours, into which are mounted two hefty 38cm paper-coned bass units, a 15cm magnesium-cone midrange driver and a 25mm fabric-dome tweeter.
Pull off the grilles front and back, and you expose the drivers, plus the massive stainless steel brace (more of a well-damped girder, actually) stabilising the layered, curved and lacquered MDF baffle - itself 43mm thick - on the heavy cast-iron base.
This design, and a weight of around 63kg – yes, per speaker – makes the R909s extremely stable. The base contains the crossover and biwire terminals.
Space not a problem
And the Jamos are very room-friendly. We had our largest room earmarked for them, but we were encouraged to try them in a smaller space, where they worked just fine on the end of our Naim/Krell reference system.
Whatever you've heard about the problems of room interaction with dipole speakers like these, the R909s just get on with the job, provided they have a metre or so of space behind them and a gentle toe-in toward the listening position.
While these speakers can indubitably do ‘big', with a rich, powerful and well-defined bass, their main characteristic is subtlety, whether with the finer details of voices or the way in which they reveal the recorded acoustic. The excellent LSO Live CDs are delivered with a real sense of performance, but the Jamos are just as happy blasting out good-time rock from The Faces or noodling through a Kate Bush disc.
They slam, they deliver the rush of a full orchestra, they let you hear each breath a singer takes and, above all, they're special.
