LS3/5A Raymond Cooke

About the LS3/5A Raymond Cooke

The KEF LS3/5A Raymond Cooke is a special edition of the legendary BBC LS3/5A monitor speaker, developed under the direct supervision of Raymond Cooke, the founder of KEF. It features a 2-way sealed-box design with an 11 cm B110C bass/midrange driver (SP1228) and a 1.9 cm T27 Mylar dome tweeter (SP1032), both strictly selected and matched to ±0.5 dB stereo pair tolerance. The enclosure is made of 12 mm thick birch plywood with a teak veneer finish, designed to be airtight with internal damping materials to reduce resonance. The crossover network uses 26 carefully selected high-quality components, with system characteristics controlled within ±0.25 dB of BBC specifications. The speaker has a nominal impedance of 11 ohms, sensitivity of 82.5 dB at 2.83 V/1 m, frequency response from 70 Hz to 20 kHz ±3 dB, and requires an amplifier power of 25-75 W into 8 ohms. Dimensions are approximately 300 mm (H) x 190 mm (W) x 170 mm (D), weighing about 5.5 kg each. It is a limited edition model with a gold plate bearing Raymond Cooke's signature, representing KEF's homage to the classic BBC LS3/5A design with modern precision and craftsmanship.