MBL 111 loudspeaker System Context
My dedicated listening room measures around 19' by 16.5', with a 9' 3" ceiling broken up by 9" pine logs. The room is carpeted, and there are patches of Sonex foam on the ceiling to damp primary reflections of the sound. The other wall has RPG Abffusors 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. 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 middle treble, falling to 150ms above 10kHz.
The MBL loudspeakers were positioned first some 33", then 45" from the rear wall (which is faced with books and LPs), and approximately 6' from the sidewalls (some of whose surfaces are also covered by bookshelves). They were spiked to the concrete floor beneath the rug/pad.
The amplifiers used were a solid-state Pass Labs Aleph 3 and a tube Audio Research VT100. The preamplifier was the remote-controlled Mark Levinson No.38S, with a Mod Squad Phono Drive EPS used to amplify LP signals from a Linn Sondek/Cirkus/Trampolin/Lingo/Ekos/Arkiv setup on an ArchiDee table. Digital source was a Mark Levinson No.30.5 HDCD D/A processor driven by a Mark Levinson No.31 transport via Madrigal and Illuminati AES/EBU cables and a Meridian 518 jitter-reduction unit.
Interconnects used were AudioQuest's AudioTruth Lapis X3; speaker cable was first a single-wired set of Cardas Cross, then a bi-wired set of AudioTruth Sterling. All source components and preamps used in my listening room were plugged into a Power Wedge 116 Mk.II, itself connected to a dedicated AC circuit and fitted with the Power Enhancer option. The amplifiers were plugged into a Power Wedge 110, again fitted with the Power Enhancer.
To get a handle on how different rooms affected the balance of the MBL 111s, I also auditioned them in the dedicated listening room at the Stereophile offices. The system there consisted of a Krell KPS-20i CD player, McCormack TLC-1 passive preamp, and a Krell KSA-250 power amplifier. Interconnects were TARA Labs RSC; speaker cabling was MIT.—John Atkinson