Полочная акустика — Martin Logan Motion Foundation B1

The Motion Foundation B1 is the smallest model in MartinLogan's Motion Foundation series, an affordable range launched in June 2023 with five loudspeakers - the F1 and F2 floorstanders, the B1 and B2 bookshelf models and the C1 centre. MartinLogan states that the series brings many of its signature technologies to lower prices, built around a new tweeter variant, the Gen2 Obsidian Folded Motion Tweeter S, and aluminium cone drivers that trickle down from its Motion XT and Motion lines.

Key specs that matter

The B1 is a two-way design, and its tweeter measures 2.4 x 2.5 cm with a diaphragm of 22.6 cm2 and dispersion of 90 degrees in both planes. A 14 cm aluminium cone woofer covers the lower band, and the crossover sits at 3,400 Hz. Response runs from 48 Hz to 23 kHz within plus or minus 3 dB. Sensitivity is 89 dB and impedance is 5 ohm. The enclosure is rear ported and stands 34.6 cm tall, 18.4 cm wide and 24.05 cm deep, figures that include feet, binding posts and grille, with a weight of 5.2 kg per speaker. Buyers pick a Black, Satin White or Walnut finish.

Engineering and use context

The Folded Motion idea is to fold a thin film into pleats, so more radiating area fits into a small frame, and the B1 mounts its tweeter in a custom Folded Motion waveguide that works with the Controlled Dispersion of the tweeter. The woofer combines its aluminium cone with a stamped steel basket and unibody cone construction, and it is backed by a non-resonant asymmetrical chamber. The crossover follows MartinLogan's McCracken-Vojtko approach, developed with anechoic and in-room measurements and blind listening tests around the low distortion goals of the Vojtko crossover. Secure-Lock grilles are held by stealth mounting tabs, and each grille can be left on, taken off or rotated to change the direction of the fabric grain. The cabinet takes a single set of 5-way binding posts, and the terminals do not support bi-wiring. MartinLogan designed the speaker to work on its own or on the optional STAND25 mounting solution.

Pairing

The recommended amplifier power is 15 to 100 watts. Within the same series the brand offers the C1 centre and the F1 and F2 towers for building a multichannel system around a pair of B1.

Alternatives

Also in the Motion Foundation series, the B2 is the larger bookshelf option, with a 16.5 cm aluminium woofer, a 3,800 Hz crossover and 90 dB sensitivity.