The Wireless Meta-verse

WE LIVE now in the wireless world, and the major loudspeaker makers have been quick to embrace it with serious-performance, near-full-range designs. But each seems to have a different idea of what a “wireless speaker” should entail. Some simply connect to an existing component stack via a supplied small wireless transmitter. Others incorporate the whole smart-speaker thang, with full multiroom audio system and Alexa-Google-Siri voice control integration.

- Daniel Kumin

KEF took a middle road with its LS50 Wireless, of which the esteemed British maker has now released a next-gen edition, the LS50 Wireless II. The new speaker looks almost identical to its predecessor but incorporates numerous innovations to incrementally upgrade sonics. Most notable is a new trick to dispose of the troublesome midrange/ tweeter “back wave” that, to one degree or another, plagues every dynamic-driver design by interacting with the forward radiating output and with the cone itself to induce small but meaningful distortions in both amplitude and time domains. Creative schemes to nullify this have, over the years, including highly damped sub-enclosures, tapered, transmission-line-like rear spaces, and strategically deployed wads of fuzz (pardon the technical terminology).

KEF’s solution in the LS50 Wireless II is a disc comprised of a newly developed Metamaterial Absorption Technology (MAT) located behind the radiating surface of its concentric Uni-Q woofer/tweeter unit. This is molded with a labyrinth-like raceway pattern—likely the fruit of many hours of high-MIPS computer-simulation time—that acts as a Helmholtz resonator (absorber) to trap unwanted sound, from a few hundred Hertz on up, before it can reflect back upon diaphragm surfaces.

Fundamentally, the LS50 Wireless II is an active, wireless evolution of a passive design KEF originally introduced to mark its 50th anniversary. (A passive edition of this upgraded design, the LS50 Meta, is also currently available.) The LS50 Wireless II retains KEF’s hallmark Uni-Q concentric woofer/ tweeter configuration, now up to a 12th generation, which positions the tweeter in the space where the dust cap of a conventional woofer would be. This layout is said to promote the smooth, controlled directivity and even off-axis response that mitigates the impact of room interactions.

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