Loudspeakers

If the 'naked' LS5/9 looks rather utilitarian then it's as well to know it was designed to be seen and heard with the tight-fitting Tygan grille left in place. So be careful how you read Graph 1 – the blue trace here is the forward response without the grille (where responses errors increase to ±3.3dB above 6kHz), rather than with as is usually the case! But let's first recap – the larger cabinet and reflex-loaded 210mm polypropylene bass/mid driver offers fundamental advantages over the smaller, closed-box LS3/5A. Sensitivity is higher despite the 27-element/3rd-order crossover, meeting Rogers' 87dB specification, at 86.6dB/1kHz and 87.2dB/500Hz-8kHz. Measured on Rogers' preferred mid-baffle axis, the forward response retains a suggestion of the 'BBC dip' through mid and presence, partially masked by undulations between 2-6kHz. These contribute to the overall ±3.0dB and ±2.4dB response errors [see Graph 1] and are reflected in the cone/surround mode seen on the CSD waterfall [see Graph 2].

The bass unit has a –6dB bandpass of 72Hz-288Hz [green shaded area, Graph 1], free of obvious spuriae until breakup, and supported by the front port, tuned to 38Hz but with a useful 29Hz-113Hz (–6dB) output. The diffraction-corrected nearfield response indicates a LF extension of 59Hz (–6dB re. 200Hz). So is this encouraging sensitivity and good bass achieved with recourse to a punishingly low impedance? Fortunately not... With relatively high minima of 5.69ohm/172Hz/–8° and 5.89ohm/2.9kHz/+2° combined with maximum phase swings of –47°/103Hz and +30°/74Hz (all >12ohm) the LS5/9 Classic SE will not prove burdensome for the 'average' integrated. PM