Motion 15i Bookshelf Speakers
The high-performance Motion 15i bookshelf speaker features a Folded Motion® tweeter, a 5.25-inch aluminum cone woofer with a rear-firing bass port, and a proprietary Vojtko crossover network to deliver refined sound with stunning dynamic range and jaw-dropping clarity. Motion 15i delivers the classic broad soundstage of the Motion Series from a newly designed enclosure enhanced by the slightest of modifications, including the drive-stabilizing dust cap design and stiffened motor suspension. The speaker’s cabinet sports a reinforced baffle and a fabric grille. Available in three stylish finishes: gloss black, matte white, and red walnut.
Powerful Aluminum Cone Mid-Frequency and Bass Drivers
Custom built, low-distortion drivers pair high-power magnet structures with aluminum cone diaphragms to deliver massive excursion and sound output, preserve minute bass details, and maximize power handling capability, all without a hint of distortion. A unique concave dust cap design reinforces the strength and rigidity of the cone while reducing break up modes.
The use of aluminum for cones maximizes rigidity and strength of the drivers without adding excessive weight. This, along with the exceptional damping properties of aluminum, ensures the smooth, non-resonant response necessary for seamless blending with high-resolution Folded Motion tweeters. An added benefit of aluminum is its outstanding thermal conduction capability which allows cones to serve as efficient heat sinks for voice coils.
To deliver accuracy in the critical midrange, mid-frequency drivers feature a specially engineered “stiff” suspension. Stiffening the suspension (the spider and surround) raises the driver’s resonant frequency and optimizes its performance to achieve a natural roll-off and inherently operate within an ideal range for a mid-frequency reproduction (as opposed to a comparably sized woofer).
Proprietary Vojtko™ Crossover Networks
Premium Motion Series speakers feature proprietary Vojtko crossover networks using polypropylene and low-DF electrolytic capacitors, custom-wound inductors, and thermal and current protection.
Vojtko crossovers are named after MartinLogan’s chief audio technologist, Joe Vojtko. His unique approach to crossover design is as big of a part of the “MartinLogan Sound” as are electrostatic and Folded Motion thin-film driver technologies. A Vojtko crossover isn’t so much a set of design requirements as it is a philosophy. Vojtko crossovers are designed in such a way that all drivers are kept within their optimal frequency range and balanced with one another. The drivers themselves are as much a part of a Vojtko crossover as are capacitors and resistors. Before the design of any crossover begins, drivers are carefully selected or designed to operate within a very intentional frequency range and with precise and predictable performance parameters. Vojtko crossovers are always built from high-quality parts, and care is taken to avoid overly complex topologies—a straightforward objective due to the careful selection of woofers and tweeters. The final (and most critical) aspect of a Vojtko Crossover is that final voicing is conducted in a space that is indicative of a real-world environment. This pragmatic approach allows MartinLogan speakers to sound their best in real-world rooms.