Loudspeakers

Front and centre of what is an entirely symmetrical, large-scale array of bass, bass/mid and mid/treble drivers is a miniature array in its own right – a 'nest' of two carbon-ply domes either side of a central beryllium dome tweeter. Perlisten calls this its Directivity Pattern Control (DPC) waveguide, an 'acoustic lens' technology that is core to the very uniform and transparent sound of these loudspeakers. In practice, all three domes combine low mass with high stiffness but are optimised over discrete bandwidths. They take over from the adjacent bass/mid cones at ~1.4kHz but the 28mm main tweeter continues to work above 4.5kHz where the two 28mm laminated (thin-ply carbon diaphragm) domes roll away.

The integration of these units, however, is key. Not only is this triple-driver array set into a dished waveguide that's mapped to the directivity of the midrange cones above and below, but the physical profile and output of each tweeter unit is designed to optimise the response and dispersion of the ensemble, controlling both the vertical and horizontal directivity. While the sophisticated drivers and very complex crossover [achieved without compromising sensitivity] are bespoke, the thinking behind this full-range line of drivers is not dissimilar to the XA (eXpanded Array) proposed in the 1980s and latterly implemented by Snell Acoustics in its asymmetrical 1999 XA90ps floorstander and tall, slim but symmetrical XA Reference Tower of 2002.

Perlisten credits Comsol's acoustic modelling software for much of the high-level number-crunching – establishing the dome size and shapes, the profile of the waveguide, fine-tuning the crossover topology and spacing between the drivers (and grille design) to optimise the tower's vertical polar pattern. Comsol modelling was first employed in high-end audio, I believe, by Edwin van der Kley Rynveld for the Siltech Pantheon loudspeaker [HFN Feb '08]. PM