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MartinLogan Motion® 4i Bookshelf speaker with wall-mount bracket

Item # 839MO4IB

Looking for excellent sound without taking up much shelf or floor space? The MartinLogan Motion® 4i offers a...

Looking for excellent sound without taking up much shelf or floor space? The MartinLogan Motion® 4i offers a...

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6 questions - 10 answers

Item # 839MO4IB

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$249.99 each

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About the MartinLogan Motion® 4i

Kramer Crane

Dynamic, space-saving sound

Looking for excellent sound without taking up much shelf or floor space? The MartinLogan Motion® 4i offers a powerful combo of musical performance and compact design. Use a pair as part of a stereo music system, or grab as many as you need for a MartinLogan surround sound system.

Dynamic, space-saving sound

Looking for excellent sound without taking up much shelf or floor space? The MartinLogan Motion® 4i offers a powerful combo of musical performance and compact design. Use a pair as part of a stereo music system, or grab as many as you need for a MartinLogan surround sound system.

MartinLogan Motion® 4i Bookshelf speaker with wall-mount bracket

MartinLogan's Motion 4i bookshelf speaker uses a Folded Motion tweeter for for fast, articulate highs.

An acclaimed tweeter delivers smooth, sweet highs

One of the reasons the Motion 4i sounds so good is its Folded Motion™ tweeter. This unique, accordion-style design is quick, accurate, and very smooth. You'll enjoy clear, natural sound throughout its frequency range. 

Since this speaker is relatively small, you may want to pair it with a powered subwoofer for deeper bass — especially for home theater applications.

Versatile design adapts to your room

MartinLogan recommends mounting the Motion 4i "right side up" at ear level, but upside down if it's above ear level. This lets it disperse sound down towards you for optimal sonic performance. It even includes the wall-mount bracket, so you can attach it to your wall for awesome sound that's out of the way.

Part of a complete MartinLogan surround sound system

The MartinLogan Motion Series features an array of speakers that are voice-matched for compatibility in an immersive surround sound system:

Got wire?

Most speakers don't include any. Read our article about choosing and installing speaker wire.
Shop our selection of speaker wire.


Product highlights:

  • elegantly curved cabinet with high-gloss piano black finish
  • 1" x 1.4" Folded Motion tweeter
  • 4" poly cone woofer with rigid dust cap
  • frequency response: 70-23,000 Hz (±3dB)
  • recommended amplifier power: 20-150 watts
  • sensitivity: 90 dB
  • impedance: 4 ohms
  • ported design with folded bass reflex port
  • perforated metal grille
  • custom-designed push-style binding posts accept pins, banana connectors, or bare wire
  • includes wall-mount bracket
  • 5-11/16"W x 12-11/16"H x 5-11/16"D
  • weight: 6 lbs.
  • warranty: 5 years (with product registration)
  • MFR # Motion 4i

High-performance amplifier recommended. See receivers & amps for this speaker

What's in the box:

  • Bookshelf loudspeaker
  • Grille
  • Two-piece wall-bracket
  • 1/4"-20 Shoulder bolt
  • 4 Self-adhesive rubber pads
  • Cleaning cloth
  • User's Manual (En/Fr)
  • Installation template
  • Product Registration Card

Customer reviews for MartinLogan Motion® 4i

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4.5 out of 5 stars
25 reviews

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More details on the MartinLogan Motion® 4i

Stacey B.

Features & specs

Enclosure Ported
Finish Piano Lacquer
Color Gloss Black
Tweeter Type Folded Motion Ribbon
Tweeter Size (inches) 1 x 1.4
Midrange Size (inches) N/A
Woofer Size (inches) 4
Woofer Composition Poly
Woofer Surround Rubber
Power Range 20-150
Sensitivity 90 dB
Impedance (Ohms) 4
Frequency Response 70-23k Hz
Connector Type Spring post
Bi-amp Inputs No
Height (inches) 12-11/16
Width (inches) 5-11/16
Depth (inches) 5-11/16
Weight (pounds) 6
Wall-mountable Yes
Bracket Included Adjustable bracket
Recommended Stand Height (inches) 28-31
Parts Warranty 5 Yrs w/ Registration
Labor Warranty 5 Yrs w/ Registration
The MartinLogan Motion® 4i replaces these items:

Product Research


Folded Motion Tweeter: MartinLogan's Folded Motion Tweeter helps give the 4i bookshelf 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 1" x 1.4" 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 (80°x80°) to create a realistic and carefully etched sound stage.

4" Poly Cone Woofer: The MartinLogan 4i loudspeaker features a 4" poly cone woofer with a stamped steel basket housed in a non-resonant asymmetrical chamber. The poly cone woofer uses a rigid structured dust cap to reduce cone break-up and distortion. This 4" cone woofer provides rich, detailed midbass.

Precision Vojtko Crossover: To seamlessly blend the audio output from the high frequency driver (tweeter) and the midbass driver (woofer), the 4i loudspeaker features a precision Vojtko crossover (2900Hz) 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 4i bookshelf 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.

Curved High-Gloss Black Cabinet: Complementing the Motion 4 loudspeaker's sonic accuracy is its elegant, yet understated styling. A high-gloss, piano black finish and subtle curves, along with MartinLogan's signature perforated grille, give the Motion 4 speaker an elegant and timeless look that will blend into almost any decor. The grille is magnetic and detachable.

Spring-Post Connectors: The MartinLogan 4i 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).

Versatile Mounting Options: The MartinLogan 4i bookshelf loudspeaker can simply be placed on a table-top, stand, shelf, or other flat surface. Four self-adhesive rubber feet are included for safe and secure placement. Using the included keyhole-slot bracket, you can wall-mount the speaker at two different angles. This means you can point sound directly toward the desired listening area for high or low wall mounting applications. In addition the 4i is fitted with a 1/4"-20 threaded insert which allows you to hang the speaker on the wall using optional articulating wall-mount brackets (sold separately).

  • If the 4i is being mounted at approximately ear-level, the speaker should be oriented with the tweeter at the top. This will disperse sound directly towards the desired listening area.
  • If the 4i is be mounted above ear-level, the speaker should be oriented with the tweeter at the bottom. This will disperse the sound down at a 20° angle towards the listening area.

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Customer Q&A

6 questions already asked

Does the speaker bracket swivel or is it fixed?
surdy  Dec 15, 2022
1 answer
The speaker can be mounted in two positions. It can be oriented to fire level or downward at a 20-degree angle. Other brackets may be used to achieve a swivel. Our advisors are happy to help with selecting the correct brackets via online chat or phone at 1-800-324-9695.
zachary  Dec 16, 2022 (Staff)
Can these be laid down sideways securely?
jonny  Aug 04, 2019
5 answers
I wouldn't recommend it.
wade  Aug 05, 2019
Yes I use pieces of Velcro ( length up to you for degree of security) on my 2 foot speaker stands. opposite sides. I prefer vertical with 2 inch lengths on 2 sides of the on the outer periphery. I use these for theater front and rear -110 wat receiver . ESL for music. As a high end audio user I have preferred ML for many years Bill San Antonio TX
william a  Aug 04, 2019
They are not made for that orientation. You could put rubber bumpers on them, but these are made to be mounted vertically. You can flip them though.
brad  Aug 04, 2019
Yes, that should work well. They come with rubber pads to apply to any side that you decide is the contact surface. They also come with a versatile mounting pedestals to attack to walls or ceilings. These speakers are excellent and perform very well.
frank  Aug 04, 2019
They certainly can be laid sideways if they were to lay on a shallow shelf. However, I'm not sure I would personally do that. They are really made to stand upright as a bookshelf speaker, or to be wall mounted with the included bracket. Laying them sideways means they would be resting on the beautiful piano finish, and may scratch it. Also, it wouldn't be so symmetrical looking. However, if they were placed nicely, and not slid around, I see no reason it wouldn't be secure. My motion 4i speakers are utilized as front left/right, and are paired with a motion 8 center channel, and motion 2i left/right surround. Also a Martin Logan Dynamo 700 sub which I think has since been discontinued and replaced with the Dynamo 800. I love my set up, they sound great. Especially after the break in period. Hope this helps.
john  Aug 04, 2019
Will these work for nearfield computer speakers?
joshua  Mar 07, 2019
1 answer
Yes, they would be perfect for nearfield computer speakers.
kim  Mar 07, 2019
How does this work with 8ohm receivers? ML claims they are compatible, but I dont see how a speaker can be 4 and 8 ohms at the same time lol.
kyle  Nov 23, 2018
1 answer
Yep. They also state as much in the specifications section of the manual: "Compatible with 4, 6, or 8 Ohm rated amplifiers". I only recommend them for use with amplification rated for 4 Ohms as many manufacturers won't honor their warranty if you use speakers that present a lower than recommended impedance. I hope that helps My bio:
ryan  Nov 28, 2018 (Staff)
Can I use a different mount other than the one it comes with. Is the mounting screw standard?
john  Nov 24, 2017
1 answer
The threaded inserts are standard and compatible with a wide range of third party wall mount brackets. You can find them all by clicking the "Accessories" tab on the speaker's main webpage. I hope that helps! My Bio:
ryan  Nov 30, 2017 (Staff)
Can you mount next to TV, are they shielded?
james  Sep 16, 2017
1 answer
The modern TV isn't affected by speakers. However, if you have a Plasma or a CRT TV, then you should not use these speakers next to it. They are not video shielded. I recommend calling an advisor on 1-800-324-9695 for a personal recommendation on speakers that work with those 2 types of TV's. My Bio:
jason  Sep 18, 2017 (Staff)

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