Audiophile performance without an audiophile price. Inspired by the clarity and detail of MartinLogan's ultra-high-end electrostatic loudspeakers, Motion 4i features a Folded Motion tweeter, 4-inch paper cone woofer, and a proprietary Vojtko crossover network in a compact and affordable package. Low-frequencies are enhanced by a rear-firing Cascading Bass Reflex Port, a unique, long-volume port that delivers surprisingly big bass from a remarkably compact loudspeaker. Flexible installation options allow table top or on-wall installation. Motion 4i can also mount upside down to facilitate placement high on a wall. Available in gloss black.

At a Glance

Model: MartinLogan Motion 4i
Sold as: Single (price is each)
Available Finishes: Gloss Black
Frequency Response: 70–23,000 Hz ±3dB
Recommended Amplifier Power: 20—150 watts per channel
Horizontal Dispersion: 80°
Vertical Dispersion: 80°
Sensitivity: 90 dB/2.83 volts/meter
Impedance: 4 Ohms Compatible with 4, 6, or 8 Ohm rated amplifiers.

Key Features

Motion 4i Compact Bookshelf Speakers
Audiophile performance without an audiophile price. Inspired by the clarity and detail of MartinLogan's ultra-high-end electrostatic loudspeakers, Motion 4i features a Folded Motion tweeter, 4-inch paper cone woofer, and a proprietary Vojtko crossover network in a compact and affordable package. Low-frequencies are enhanced by a rear-firing Cascading Bass Reflex Port, a unique, long-volume port that delivers surprisingly big bass from a remarkably compact loudspeaker. Flexible installation options allow table top or on-wall installation. Motion 4i can also mount upside down to facilitate placement high on a wall. Available in gloss black.

Engineering, Without Compromises
What makes the Motion Series sound so amazing? MartinLogan's dedicated in-house engineering and design team started by utilizing and refining the most advanced, compact technologies and combining them with innovative engineering and time-honored cabinet construction techniques. The result is an emotionally engaging sound that rivals (and most times trounces) traditional loudspeakers of similar size and price. Our 'no compromise' philosophy gives Motion Series a unique sound you won't find anywhere else.

Sound Inspired by Electrostatic Speakers
The success of the Motion Series is directly attributed to its close relation to MartinLogan’s legendary ultra-high-end electrostatic loudspeakers. The desire to transmute that level of performance into a more traditional loudspeaker at a more affordable price drove the initial design imperatives that created the Motion Series.

Folded Motion® Tweeters
MartinLogan's signature Folded Motion tweeter utilizes an extremely low mass diaphragm that "squeezes" air, thus demanding significantly less excursion than the typical 1-inch dome tweeter. Its folded design allows for a much larger surface area (compared to that of a regular 1-inch dome tweeter), controlled dispersion characteristics, and vanishingly low distortion. It's a miracle of audio engineering that's able to deliver much of the high-frequency detail and speed of a large, dynamic electrostatic panel in a small space.

Proprietary Vojtko ™ Crossover Networks
Compact Motion Series speakers feature proprietary Vojtko crossover networks using custom air core coil inductors, low DCR steel laminate inductors, and polyester film and low-DF electrolytic capacitors for a seamless sonic presentation.

Modern Curves and Luxurious Finish
After refining the perfecting the acoustic details, MartinLogan designers focused on elegant yet understated styling that complements flat-panel televisions and other high-end components. To achieve this, we gave compact Motion bookshelf and center channel speakers a flawless gloss black finish and compact, slender enclosures. Subtle curves, along with MartinLogan's signature perforated grille, add to the elegant and timeless look.

Versatile Placement—On a wall, Shelf, or Stands
Not only do the curves on the compact Motion bookshelf speaker Series look great, but they also serve a purpose—allowing them to mount at two different angles with the included wall bracket. This means you can point sound directly toward the desired listening area for high or low wall mounting applications. Motion 2i and 4i speakers don't have to be mounted. In fact, they look and sound great on speaker stands, or sitting next to your TV on a shelf.

Easy Hookup
Convenient, high-quality, push-style binding posts are recessed into the speaker's cabinet along with curved guides that allow wires to slide into place effortlessly. These binding posts are also designed to facilitate the use of banana plug connectors.

Cascading Bass Reflex Port
MartinLogan engineers were faced with a daunting task—create a compact speaker with low-end bass reproduction found in speakers much, much larger. After many sleepless night and a myriad of prototypes, they created the Cascading Bass Reflex 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 4i. 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.

Frequency Response	70–23,000 Hz ±3dB
Recommended Amplifier Power	20—150 watts per channel
Horizontal Dispersion	80°
Vertical Dispersion	80°
Sensitivity	90 dB/2.83 volts/meter
Impedance	4 Ohms Compatible with 4, 6, or 8 Ohm rated amplifiers.
Crossover Frequency	2,900 Hz
High Frequency Transducer	1" × 1.4" (2.6cm × 3.6cm) Folded Motion Transducer with 5.25" × 1.75" (13.3cm × 4.4cm) diaphragm
Low Frequency Transducer	4" (10.2cm) paper cone with stamped steel basket. Non-resonant asymmetrical chamber format. Rigid structured dust cap to reduce cone break-up modes. Folded bass reflex port.
Components	Custom air core coil and low DCR steel laminate inductors. Polyester film capacitors in series and low DF electrolytic capacitors in parallel. Overall system thermal/current protection.
Inputs	Push style with banana jacks
Weight	6 lbs. (2.72 kg)
Dimensions	12.6" x 5.6" x 5.7 " (32cm x 14.3cm x 14.5cm)