MartinLogan Foundation B1

The most compact model in the Motion Foundation series, sold as a pair: a two-way standmount with a Folded Motion S tweeter and a 14 cm aluminium woofer, suited to small rooms and to partnering with a subwoofer.

Foundation B1: drivers and cabinet

The Foundation B1 is a two-way speaker for a shelf or a stand, 34.6 cm tall and 18.4 cm wide, weighing 5.2 kg. MartinLogan intends it for small spaces and suggests adding a subwoofer where more extension is wanted: on its own it covers 48 Hz to 23 kHz within ±3 dB. It has threaded fixings for the brand's STAND25 stand, which gives it a stable footing when used on a stand.

The 14 cm woofer handles bass and midrange up to 3,400 Hz, where the two-way crossover passes the signal on to the tweeter. Its Unibody aluminium cone is mounted in a stamped steel basket and loaded into an asymmetrical chamber that counters resonances; the reflex port opens at the back of the cabinet. An 89 dB sensitivity and 5 ohm impedance suit it to amplifiers of 15 to 100 watts.

The tweeter is the same one fitted to the larger models: a second-generation Folded Motion S whose thin-film diaphragm is folded many times to give 22.6 cm² of surface in a 24 x 25 mm unit. Low moving mass and small excursion favour speed of response and the rendering of fine detail. The waveguide surrounding it controls its dispersion, 90° in both planes, and reduces the influence of room reflections.

Specifications

• Type: two-way standmount or shelf speaker, rear-ported
• Frequency range: 48 Hz to 23 kHz, ±3 dB
• Impedance: 5 ohms
• Sensitivity: 89 dB
• Amplifier power: 15 to 100 W
• Crossover point: 3,400 Hz
• Tweeter: 24 x 25 mm Folded Motion S Gen2, 22.6 cm² diaphragm
• Tweeter coverage: 90° horizontal, 90° vertical
• Woofer: 14 cm Unibody aluminium cone, stamped steel basket
• Cabinet: bass reflex, port at the rear
• Terminals: five-way posts, single-wire only
• Grille: magnetic cloth grille over the woofer
• Matching stand: STAND25 (threaded fixing)
• Size (H x W x D): 34.6 x 18.4 x 24.05 cm
• Weight: 5.2 kg
• Supplied: sold as a pair
• Finishes: black, white, walnut