Loudspeakers

Taking centre stage in the S7t LE tower, and nestled into a CNC-machined alloy Directivity Pattern Control (DPC) waveguide, are two carbon-ply domes either side of a beryllium dome tweeter. Dubbed ‘acoustic lens’ technology, 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 ~1.2kHz but the 28mm main tweeter continues to work above 4.8kHz where the two 28mm laminated (thin-ply carbon diaphragm) domes roll away.

Perlisten employed Comsol’s acoustic modelling software to work on the dome sizes, shapes and spacing, the waveguide’s contours and fine-tuning of the crossover. 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. The LE version’s all-alloy waveguide improves heatsinking and power handling while the crossovers are adjusted so the mid domes now operate over a slightly wider 1.2-4.8kHz from the S7t’s 1.4-4.5kHz. Integration remains key, however, so the dished waveguide still ensures the triple-driver array is optimally mapped to the directivity of the ‘Textreme’ cones situated immediately above and below. PM