MartinLogan Motion FX

Surround speaker (Black)

Item #: 839MOFXB

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Wide-dispersion design creates atmospheric sound

MartinLogan Motion 30 center channel speaker

MartinLogan's advanced Folded Motion tweeter produces clear, open sound.

The most effective surround speakers are the ones you barely notice, like MartinLogan's Motion FX. Like the other Motion models, the Motion FX employs one of MartinLogan's most advanced technologies, the Folded Motion™ tweeter. In fact, it uses two of them in a wide dispersion configuration that creates an atmospheric home theater experience. The Motion FX is the ideal surround speaker choice for MartinLogan's other Motion series speakers.

Folded Motion tweeter for detailed sound

MartinLogan's innovative Folded Motion tweeter uses a pleated diaphragm that works like an accordion by "squeezing" air to create sound. It requires about 90% less excursion than a typical 1" dome tweeter, resulting in quicker response time and much lower distortion. The Motion FX has two of these tweeters, aimed away from each other, to disperse ambient sound — effects, music, voices — so that you're fully immersed in whatever scene is playing out on-screen.

Midrange and lower frequencies are handled by a single 5-1/4" woofer. A rear-firing port gives the speaker a little extra bass oomph.

Versatile mounting options

When it comes to surround speakers, placement is important. The Motion FX offers multiple mounting options to suit a variety of rooms and configurations. Conventional wall-mounting is easy with the supplied hardware. Plus, the back sides are angled at 45 degrees to allow for wall/wall corner mounting or wall/ceiling mounting.

Product Highlights:

  • wide-dispersion design with dual tweeters and a single woofer
  • dual 1" x 1.4" Folded Motion tweeters for exceptional detail with low distortion
  • 5-1/4" paper cone woofer
  • Folded Bass Reflex Port design for enhanced bass output
  • frequency response: 74-25,000 Hz (±3dB)
  • sensitivity: 91 dB
  • impedance: 4 ohms
  • recommended power: 20-160 watts
  • convenient push-style speaker binding posts (also compatible with banana plugs)
  • versatile on-wall mounting options including corner-mounting
  • voice-matched to MartinLogan's Motion series tower, bookshelf, and center channel speakers
  • 12"W x 11-1/8"H x 6"D
  • weight: 9.5 lbs.
  • warranty: 5 years (with product registration)
  • Our 60-day money-back guarantee
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Hands-on research

What's in the box?

  • Surround loudspeaker
  • 2 Wall-mount brackets
  • Shoulder-bolt
  • 2 Rubber bumpers
  • User's Manual (En/Fr) Installation template
  • Product Registration Card

Product Research


Folded Motion Tweeter: Two 1" x 1.4" Folded Motion tweeters help give the Motion FX surround loudspeaker its natural, realistic high frequency sound. Lightning fast transient response, combined with a large surface area (8x that of a typical 1" dome tweeter) creates clear, dynamic, and precise sound. The Folded Motion tweeter works by moving air (which creates sound) perpendicular to the folded ridges of the diaphragm, similar to how an accordion works. This extremely low mass diaphragm "squeezes" air and requires almost 90% less excursion than the typical 1" dome tweeter, which drastically minimizes distortion while providing a lightning fast response time. The increased surface area also provides a wide, yet controlled sound dispersion to create a realistic and carefully etched sound stage. The two 1" x 1.4" Folded Motion tweeters have a combined dispersion area of 160° x 80°.

5.25" Paper Cone Woofer: The MartinLogan Motion FX surround loudspeaker features a 5.25" paper cone woofer with a cast aluminum basket housed in a non-resonant asymmetrical chamber. The paper cone woofer uses a rigid structured dust cap and butyl rubber surround to reduce cone break-up and distortion. This 5.25" cone woofer provides rich, detailed midrange/midbass.

Precision Vojtko Crossover: To seamlessly blend the audio output from the dual Folded Motion tweeters and one 5.25" woofers, the Motion FX loudspeaker features a precision Vojtko crossover (4500Hz) utilizing custom air core coil and low DCR steel laminate inductors, polyester film capacitors in series, and low DF electrolytic capacitors in parallel.

Folded Reflex Port Technology: MartinLogan engineers were faced with a daunting task, create a compact speaker with low-end bass reproduction found in speakers much larger. After a myriad of prototypes, they created the Folded Motion Cascading Bass Port. This brilliant solution allows a long tuned port, which is folded over itself (think of a trombone's tuning arm) to be compacted and squeezed into the Motion FX loudspeaker. The result is amazingly detailed low bass that can play at high volumes with minimum distortion; all thanks to the elegantly simple cascading fold that slows down and controls the air motion of the bass waves. The Folded Motion Cascading Bass Port exits the rear-panel of the speaker cabinet.

Spring-Post Connectors: The MartinLogan Motion FX speaker features two spring-post connectors to attach your speaker wire. The spring-posts will accept bare wire (16- to 10-gauge), pin-connectors, and banana plugs (single only). The rubber caps on the spring-post connectors must be removed to use banana plugs.

Applications: The MartinLogan Motion FX can used as a rear or side surround speaker in a home theater application for any size room.

Mounting Options: The MartinLogan Motion FX surround loudspeaker can simply be placed on a table-top, stand, shelf, or other flat surface. Two self-adhesive rubber feet are included for safe and secure placement. Using the included keyhole-slot bracket, you can wall-mount the speaker against a flat wall, in a corner, or angled on a wall.

Break-in Period: Allow approximately 72 hours of break-in at 90 dB (moderate listening levels) before any critical listening.

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