Motion 4i

Stylish and Compact

Inspired by MartinLogan's ultra-high-end electrostatic loudspeakers, the Motion® Series was created to provide stunning sound for your ultimate-performance home theater or stereo. MartinLogan's dedicated in-house engineers carefully crafted the Motion Series to create an extremely affordable and compact product line that seamlessly blends our exquisite Folded Motion® transducers with powerful, compact bass technology. The result is a smooth, refined sound with stunning dynamic range and jaw-dropping clarity.

$249.99 each
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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.

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.

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.


"Spare Change YouTube Video"

—Shane Bolin, Spare Change
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$249 MartinLogan Motion 4i Review

"I haven’t heard anything that comes even close to sound quality of the MartinLogan Motion 4i at anywhere near their price point."

—George Graves, Audiophile Style
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When You Become Attached- MartinLogan Motion 4i Speakers and Dynamo 800X Subwoofer

"I was already a fan of MartinLogan products, loving their speakers such as the $80,000 Neolith, but wasn’t sure how much the quality trickled down into the lower-priced products. Consider me impressed. I have not seen many products in these price ranges that can compete, and certainly none that look as good."

—Michael Laurance, The Shoestring Audiophile
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MartinLogan Motion 4i Bookshelf Speaker

"A lot of technical knowledge and clever engineering went into the design of the MartinLogan Motion 4i bookshelf speakers. They’ve succeeded at a low price."

—Mel Martin, Secrets of Home Theater and High Fidelity
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[YouTube Video] Martin Logan Motion 4i, 8i Speakers and Dynamo 600X Subwoofer Unboxing & Review

"Techno Dad YouTube Video"

—Channa De Silva, Techno Dad
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MartinLogan Motion Speakers & Dynamo 800 Sub 5.1 Speaker System Review

"When space is at a premium, but you refuse to cut corners when it comes to audio fidelity, a system comprised of MartinLogan’s Motion 4i, 8i and Dynamo 800X is a solution that I enthusiastically recommend."

—Mark Henninger, AVS Forum
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MartinLogan Motion 4i Loudspeakers

"If you’re looking for something different, and an involving listening experience, I highly recommend that you give the MartinLogan Motion 4i an audition."

—Vince Hanada, SoundStage! Access
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The MartinLogan Motion 4i: Take em Outside!

"Just as MartinLogan has done with their hybrid ESL speakers, the seamless blend between the Motion tweeter and the woofer feels like you are listening to a full range speaker. There is a level of transparency here that just doesn’t happen with other budget small speakers and that’s impressive."

—Jeff Dorgay, TONEAudio
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MartinLogan Motion 4i Bookshelf Speaker Reviewed

"After listening to the Motion 4i, I can attest that this is a very cool little speaker. There are several features the wizards at MartinLogan packed into the speaker that influences its ultimate final sonic signature, but before we dig into that, it's worth asking: what is this speaker, anyway? Is it a near-field monitors for musicians and recording engineers? Is it a good right and left option in an audiophile 2.1 system? Is it good for the right, left, and surround duties of a surround sound system? Is it an option for a computer playback system? The answer to all of the above: yes, yes, yes, and yes!"

—Scott Schumer,
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MartinLogan Motion 4i and 8i Speakers

"If you’re not familiar with the original Motion Series speakers, their performance can best be summed up in two words: “detailed” and “dynamic.” Much like the originals, the amount of sound coming out of these little cabinets is a bit startling. "

—Dennis Burger, Residential Systems
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Specifications are subject to change without notice

Frequency Response

70–23,000 Hz ±3dB

Recommended Amplifier Power

20—150 watts per channel

Horizontal Dispersion


Vertical Dispersion



90 dB/2.83 volts/meter


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.


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.


Push style with banana jacks


6 lbs. (2.72 kg)


12.6" x 5.6" x 5.7 "
(32cm x 14.3cm x 14.5cm)

Customer Reviews For Motion 4i

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anthony Z.

  • Friday, October 29, 2021

Outstanding sound quality.


  • Wednesday, March 24, 2021

I use the 4's for my back surrounds... I scared myself the first time I used them because I wasn't ready for the superbness.

Major J.

  • Wednesday, January 20, 2021

I use these as my side surrounds and back surrounds..... They did not disappoint. Incredible sound and clarity. Thank you, Martin Logan!

damion G.

  • Monday, April 8, 2019

I just bought a pair of these at Best Buy. In the store they sounded good enough, but when I got home and hooked them up, WOW! I can not believe how these speakers sound. Seriously, these are some really good speakers. So crisp. So dynamic for the size. I want another pair now.