Bookshelf Speakers — Graham Audio BBC Licensed LS5/8

The LS5/8 is a large two-way monitor made under BBC licence by Graham Audio of Britain, which produces current versions of historic BBC studio monitors. The original came from the BBC Research and Development department in the late 1970s as one of its last major loudspeaker projects, intended for studio monitoring of both classical and rock recordings. It was created because studios needed higher sound pressure levels than the smaller LS5/9 could deliver. The current version appeared in 2015 and was developed with Derek Hughes and Volt Loudspeakers, and the UK price was GBP 6,995 per pair, or GBP 7,295 in cherry.

Key specs that matter

A 300 mm polypropylene bass and midrange driver made by Volt works with a 34 mm Audax tweeter, the same tweeter used in the LS5/9, behind a protective metal grille. The cabinet is reflex loaded with an internal volume of 109 litres. Frequency response is 40 Hz to 16 kHz within 3 dB, nominal impedance is 8 ohm and sensitivity is 89 dB SPL for 2.83 V at 1 m. A pair can reach more than 110 dB at 2 m. Each speaker is 76 cm high, 46 cm wide and 40 cm deep and weighs 34 kg.

Engineering and use context

The BBC ran the first LS5/8 as an active speaker, driven by a modified Quad 405 amplifier known inside the corporation as the AM8/16 and later by dedicated Chord Electronics amplifiers. For the Graham model Derek Hughes converted it to passive operation, which he notes is harder than it looks, because changes in driver impedance are no longer isolated from the filter as they are in an active system. His crossover divides the band at 1.8 kHz with 19 precision components, using an 18 dB per octave slope on the tweeter and 12 dB per octave on the woofer, and it still meets the BBC specification. The enclosure follows the BBC thin-wall approach, with 12 mm birch plywood panels and hardwood battens. The panels are mass-loaded to push their resonances away from the midrange, and Rockwool rather than cheaper foam provides the internal air damping. Compared with the LS5/9, the larger cabinet and bass unit give extended low frequency reach and more headroom at high levels in bigger spaces.

Pairing

Graham recommends amplifiers from 50 to 250 W for clean playback of programme material, and the nominal load is not a difficult one for amplifiers in that power class. Because of its height and weight the LS5/8 needs rigid, heavy stands for stability.

Alternatives

The Graham Audio LS5/9 is the more compact BBC-licensed standmount monitor in the Graham catalogue.