MartinLogan Motion 4i Bookshelf Speaker - Black - Each

The Small Motion That Mounts on a Wall

The Motion 4i is a compact two-way from MartinLogan's Motion i series. A Folded Motion tweeter with a 5.25 by 1.75 inch diaphragm sits above a 4-inch paper-cone woofer in a curved, gloss black cabinet 12.6 inches tall. A wall bracket is included, and it is sold by the each.

The Folded Motion tweeter is the reason to buy a Motion speaker. A pleated film diaphragm squeezes air between its folds, so it needs about 90 percent less travel than a 1-inch dome. That means low distortion and fast transients, the same idea MartinLogan uses in its electrostatic panels.

Built for Placement Flexibility

The curved cabinet mounts at two angles on the included bracket, and can be flipped upside down for high wall positions. It also sits on a shelf or stand. A folded bass-reflex port keeps the cabinet small, and a Vojtko crossover with air-core inductors handles the 2,900 Hz hand-off.

The Numbers, and What They Ask of You

MartinLogan quotes 70 Hz to 23 kHz within 3 dB and 90 dB sensitivity. Impedance is 4 ohms, compatible with amplifiers rated for 4, 6 or 8 ohms. Recommended power is 20 to 150 watts, and dispersion is 80 degrees both ways. The 70 Hz limit tells you a subwoofer belongs in the plan.

How Much Room It Takes

Each cabinet is 5.6 inches wide, 12.6 tall and 5.7 deep, and weighs 6 pounds. The finish is high-gloss black with MartinLogan's perforated steel grille. Push-style terminals accept bare wire, and their caps come off for banana plugs.

What Reviewers Are Saying

Mel Martin reviewed the Motion 4i for HomeTheaterHifi on March 27, 2019: "They provide a stable stereo image, lovely smooth high frequencies from their Folded Motion design tweeter. The bass is thin, but the company offers its own subwoofers."

Jeff Dorgay of TONE wrote in November 2018: "The resolution of the folded motion tweeter feels like you're listening to headphones", and found the 4i equally at home on a desk and in a small room.

Dennis Burger reviewed the 4i for Residential Systems in August 2018, summing up the Motion sound in two words: "detailed" and "dynamic." He added that "the amount of sound coming out of these little cabinets is a bit startling."

Who Is This Speaker Best For?

• You want MartinLogan detail on a desk or a wall — three reviewers heard the tweeter as the star, and the bracket is in the box
• You are building a compact home theater — the 4i works as front, surround or height channels with the Motion 6i center channel and a subwoofer
• You have a small room — 90 dB sensitivity and 20 watts fill a bedroom or office
• You want full bass without a subwoofer — the 4i stops at 70 Hz; add a subwoofer, or choose the Motion Foundation B1, which reaches 48 Hz in a conventional cabinet
• Your amplifier is only rated for 8 ohms — the 4i is a 4 ohm speaker; most modern amplifiers are fine, but check the rating

How Do They Connect to Your System?

Speaker cable runs from your amplifier or receiver to the push terminals, red to red and black to black. Remove the rubber caps to use banana plugs. These are passive speakers, so there is nothing else to power.

On a wall, use the included bracket and pick the angle that aims the tweeter at the seats. On a desk or shelf, pull the speaker a little forward so the rear port can breathe. With a subwoofer, cross over near 80 to 100 Hz.

Pairs Well With

What finishes the setup. These are the categories most Motion 4i owners shop next.

• MartinLogan Dynamo 10 subwoofer — every reviewer reached for a subwoofer; this is the matching one
• Motion 6i center channel — the matching center for a Motion i home theater
• AV receivers — a receiver with room correction sets the crossover for you
• Speaker stands — for a desk-free stereo setup, 26 to 28 inches puts the tweeter at ear height

Frequently Asked Questions

Is the price for one speaker or a pair?

One speaker. Order two for stereo, or more for surround and height channels.

Is the wall bracket included?

Yes. The bracket mounts the 4i at two angles, and the speaker can be flipped for high wall positions.

Do I need a subwoofer?

For anything beyond casual listening, yes. The 4i reaches 70 Hz, and HomeTheaterHifi heard hardly anything below that. A small subwoofer completes it.

How much amplifier does it need?

MartinLogan recommends 20 to 150 watts. At 90 dB sensitivity a small receiver is enough, but the 4 ohm load means the amplifier should be comfortable with 4 ohm speakers.

How is the 4i different from the Motion 2i?

The 4i has a larger tweeter, a 4-inch ported woofer and bass to 70 Hz. The Motion 2i is smaller still, sealed, and reaches 110 Hz, so it is a surround or desktop speaker that always wants a subwoofer.

Can it be used as a surround speaker?

Yes. Wall mounting and 80 degree dispersion make it a natural surround or height channel in a Motion system.

See It in Action

Shane Lee reviews a Motion i system with the 4i as surrounds:

Techno Dad unboxes and reviews the Motion 4i and 8i:

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Learn More

Want to learn more about speaker placement, amplifier matching, or when to add a subwoofer? Visit our Learning Center for guides, tips, and expert advice.