Loudspeakers

While B&W's ingenious 150mm Continuum Cone midrange is a common link across the 600, 700 and flagship 800 series loudspeakers, their respective treble units show marked differences. All employ diaphragms that are both light and stiff, pushing the dome's primary breakup to as high an ultrasonic frequency as possible. Nevertheless, the choice of materials impacts directly on the achievable performance. For example, the costly 'Diamond' dome employed in the 800 series pushes its resonance out to 75kHz, the peak suppressed to a level below the mean midband output of the speaker. The 'Carbon' treble dome used in the 700 series breaks up at a slightly lower (but still very high) 48kHz, albeit at an amplitude some +7dB above the speaker's mean output [see HFN Sep '20].

With less budget to play with in the 600 series, and aluminium alloy the default material of choice, B&W's engineers developed a novel solution to push the 25-30kHz resonance of a standard alloy dome out to higher frequency. Here, at the rear of its 25mm alloy dome, is yet another dome, a reinforcing 'twin' but with its centre removed. This laminate – the 'Decoupled Double Dome' – raises the first break-up frequency to 36-37kHz even if the peak is very prominent at +15dB above the 603 S2 Ann. Edition's midrange level. For B&W, this is the art of compromise. PM