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go to: Contents | Features | Bookshelf, Stand-Mount and Desktop | Floorstanding | Editors' Choice Awards<br />
KEF LS50<br />
Star Power<br />
Neil Gader<br />
Some speakers sure know how to make an entrance. They just have a presence<br />
when you first encounter them. I know that’s how I felt when I crossed paths<br />
with the KEF LS50 a few months ago. At a glance, this two-way bass-reflex<br />
compact looks like little more than a stout box-speaker from an indeterminate era—as<br />
simple as it gets. But then you realize you can’t take your eyes off it. Designed to<br />
celebrate KEF’s 50th anniversary, it tips its hat to the BBC monitors of the 70s. But<br />
the LS50 is not an exercise in nostalgia. It bears zero resemblance inside or out to<br />
the birch-ply two-ways of that era—popularized by Spendor, Rogers, Harbeth, and, of<br />
course, KEF.<br />
Beyond its modest silhouette, KEF has designed<br />
the LS50 with enough innovations to stuff a<br />
piñata. It’s visually striking with its high-gloss<br />
finish and the KEF logo discreetly etched onto<br />
a corner of the top panel. The pink-gold (a nice<br />
50 th Anniversary touch) diaphragm of the Uni-Q<br />
driver is a pure KEF-designed coaxial unit and the<br />
star of its current generation of speakers. Bearing<br />
little relation to the deep-throated coaxials of<br />
yesteryear, KEF’s latest-generation coincident<br />
was designed particularly for the LS50. It’s<br />
positioned dead center in a radically curved onepiece<br />
front baffle—an incredibly dense, plastic<br />
compound which tapers to softly rounded edges.<br />
According to the design team, the 5.25"<br />
magnesium-aluminum alloy midrange driver uses<br />
a mechanism to damp diaphragm resonances,<br />
so the usual peak in response common to metal<br />
cones is ameliorated. According to KEF, the nowfamiliar<br />
“tangerine” waveguide uses radial air<br />
channels to produce spherical waves up to the<br />
highest frequencies—and this allows a deeper<br />
“stiffened dome” diaphragm that raises the first<br />
resonance, culminating in response that extends<br />
beyond 40kHz. Collectively these technologies<br />
ensure wide and even dispersion without<br />
interference between drivers.<br />
Despite the LS50’s obvious physical differences<br />
from the Blade, these speakers have much in<br />
common. KEF has applied many of the same<br />
engineering principles for coincident-driver<br />
technology, internal damping, and innovative baffle<br />
design. The unique curvature and composition of<br />
the baffle is directly related to the Blade project<br />
and is designed to mitigate diffraction effects and<br />
spurious reflections—keys to good soundstaging<br />
and imaging. The elliptical reflex port is offset in an<br />
upper corner of the rear panel. Its profile reduces<br />
44 Guide to High-Performance Loudspeakers www.theabsolutesound.com<br />
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