Harbeth BBC LS5/12A loudspeaker System Context
Power amplifiers used to drive these speakers were a pair of Mark Levinson No.20.6 monoblocks; the preamplifier was the remote-controlled Mark Levinson No.38S. A Mod Squad Phono Drive EPS amplified LP signals from a Linn Sondek/Cirkus/Trampolin/Lingo/Ekos/Arkiv setup sitting on an ArchiDee table. Digital source was a Mark Levinson No.30 driven by a Mark Levinson No.31 transport via Madrigal AES/EBU cable and an Audio Alchemy DTI•Pro or a Sonic Frontiers UltrajitterBug.
Interconnects used were AudioQuest's AudioTruth Lapis x3; speaker cable was a bi-wired set of AudioTruth Sterling. All source components and preamps were plugged into a Power Wedge 116, itself plugged into one of my listening room's two specially installed dedicated AC circuits and fitted with the Power Enhancer option. The speakers sat on 24" lead-shot–filled Celestion Si stands, interfaced to the stand top-plates with small pads of Blu-Tack. The stands were spiked to the tile-on-concrete floor beneath the carpet and pad.
My dedicated room measures approximately 19' by 16.5', with a 9' ceiling. The wall behind the speakers is faced with books and LPs, while further book- and CD shelves occupy the positions on the sidewalls where the first reflection from each speaker would occur. The room is carpeted, and there are patches of Sonex foam on the ceiling to damp the first reflections of the sound. The other wall has RPG Abffusors and ASC Tube Traps behind the listening seat to absorb and diffuse what would otherwise be early rear-wall reflections of the sound that might blur the stereo imaging precision. More Tube Traps are used in the room corners to even out the room's bass resonances, the result being a relatively uniform reverberation time of around 200ms from the upper bass to the mid-treble, falling to 150ms above 10kHz. The room sounds relatively dry, without a lot of bass bloom, but is extremely articulate.—John Atkinson