KEF LS50 Meta Moss Green (Pair)

The KEF LS50 Meta sits at the heart of KEF’s passive speaker range, slotting above the Q Series bookshelf models and below the R Series standmounts. Originally launched in 2012 as a 50th anniversary model, the LS50 has been comprehensively re-engineered for the Meta generation with KEF’s Metamaterial Absorption Technology — a development significant enough to earn What Hi-Fi?’s Innovation of the Year award in 2020.

Metamaterial Absorption Technology

At the core of the LS50 Meta is KEF’s patented Metamaterial Absorption Technology (MAT). This is a highly complex maze-like structure fitted to the rear of the tweeter dome that absorbs 99% of the unwanted sound radiating from the back of the driver. By eliminating this rear-wave energy, MAT reduces distortion and colouration that would otherwise reflect off internal surfaces and re-emerge through the cone, resulting in purer, more natural high-frequency reproduction.

12th Generation Uni-Q Driver Array

The LS50 Meta uses KEF’s 12th generation Uni-Q driver array, a coaxial design that places the 25mm vented aluminium dome tweeter at the acoustic centre of the 130mm aluminium cone mid/bass driver. This arrangement means both drivers radiate sound from a single point, delivering consistent tonal balance across a wide listening area — every seat gets the full frequency range without the comb-filtering effects common to conventional two-way designs with physically separated drivers.

Cabinet Construction

The baffle is injection-moulded from Dough Moulding Compound (DMC), a material chosen for its high internal damping and rigidity. Inside the cabinet, cross-bracing and Constrained Layer Damping (CLD) work together to suppress internal panel vibrations. KEF claims this combination delivers the lowest cabinet colouration of any speaker in its class. The rear-firing bass reflex port uses a patented off-set design whose flare profile was optimised using Computational Fluid Dynamics to delay the onset of port turbulence, with flexible port walls that further resist midrange coloration. The LS50 Meta is available in a range of colourways including the distinctive Moss Green finish, which features a coloured baffle contrasting with a complementary cabinet.

Driver Performance Optimisation

Beyond the introduction of MAT, KEF’s engineers re-examined every aspect of the Uni-Q motor system. Driver Performance Optimisation encompasses a redesigned motor geometry that reduces non-linear distortion across the operating bandwidth. The result is a measurable step forward over the first-generation LS50: KEF quotes mid-band total harmonic distortion of under 0.07% at 90dB at one metre, which is exceptionally low for a speaker at this price point.