Loudspeakers

Commercial Director and CTO, Oliver Thomas, kick-started the fenestria project in 2013 as an exercise in 'blue sky thinking'. PMC's iconic midrange dome was to remain at the heart of the speaker but it was also an opportunity to evolve its design. Improving the dissipation of the dome's rear radiation was key, so did PMC look at the frequency-selective metamaterial approach to damping seen in KEF's LS50 Meta [HFN Jun '21]?

'Not directly', admits Oliver, 'though we do have a parallel technology in development'. The design goals for the fenestria were arguably broader in scope, both in reducing driver distortion and minimising cabinet noise.

For example, the curved side panels act as tuned mass dampers, working in anti-mode to the main cabinet resonances. 'These panels are working hardest below 100Hz', reveals Oliver, 'and we have chosen the compliance of the rubber mounts, in tandem with the mass of the curved panels, to best achieve this. The position of the mounts is critical too, situated at points of maximum displacement'.

Where does the fenestria take PMC? 'There's new tech, including a smaller mid dome already used in our ci140 on-wall speakers. Also the anti-vibration mounts inspired the decoupling between the cabinet and plinth in our twenty5i series. The bass units are so expensive to manufacture there's a limit to what we can put them into', laughs Oliver, 'but there's a deal of learning here that'll inevitably trickle down into our domestic designs'. PM