MartinLogan Motion SLM On-Wall Loudspeakers and Dynamo 700w Subwoofer

April 2013

MartinLogan Motion SLMMartinLogan is a loudspeaker manufacturer based in Lawrence, Kansas. Founded by Gayle Martin Sanders and Ron Logan Sutherland, the company is best known for their extensive line of electrostatic speakers. In 2005, ShoreView Industries, a private-equity firm that also owns a stake in Paradigm, bought MartinLogan. Although the design staff is still based in Lawrence, much of the manufacturing has been moved to Paradigm’s facility in Mississauga, Ontario, Canada.

Electrostatic (ESL) speakers are renowned for the lightning-fast transients that audiophiles crave. To the non-audiophile, electrostatic speakers simply look cool. However, they’re expensive to make -- it’ll cost you about $2000 USD to take home a pair of the cheapest ESLs made by MartinLogan. MartinLogan recently introduced its Motion line of entry-level models, with traditional cabinets and conventional cone midrange-woofers. What sets the Motions apart from most entry-level speakers is their tweeter, MartinLogan’s Folded Motion Tweeter (FMT), said to sound similar to electrostatic drivers. For this review, MartinLogan sent me a 5.1-channel system based on the Motion SLM, a thin-profile on-wall speaker.


Although the Motion SLM ($499.95 USD each) measures 25.3”L x 6.4”W by only 1.83” deep, the box it comes in is quite a bit bigger: 37”L x 12”W x 8”D. The boxes for the five speakers took up a lot of space in my storage room. There’s a reason for the big box, though -- MartinLogan includes everything you need to mount the SLM (pronounced slim) any way you choose, including screws and drywall anchors. For wall mounting, a thin bracket is provided with two mounting points that fit the keyholes on the speaker’s rear panel. Or the SLM can be supported by a short stand, which also attaches to the back of the speaker. For horizontal use of the SLM as a center-channel speaker, two brackets attach to the back. These have leveling bolts that allow you to aim the SLM up or down, depending on where it’s placed. I used all three mounting methods in my home theater: front left and right speakers on the wall, brackets for the center-channel, and stands for the left and right surrounds. All three methods were easy to implement -- it took just minutes to set up all five speakers.

Outwardly, the Motion SLM looks similar to Definitive Technology’s superslim Mythos XTR-50, which I reviewed a while back. It has a high-gloss black cabinet with plastic back and sides and aluminum front. On the rear is a single pair of spring-push terminals; on the front, the grille is held in place magnetically. Remove this to see, at the center, the Folded Motion Tweeter; above and below this are a 4” paper-cone midrange-woofer and a passive 4” paper-cone radiator. The FMT is a ribbon of thin film, folded accordion-style to fit into a 1” x 1.4” space. The tweeter works by squeezing air between its folds to create soundwaves. According to MartinLogan, if this ribbon were unfolded and laid out flat, it would be seen to have eight times the radiating area of a conventional 1” dome tweeter. Much like MartinLogan’s electrostatic speakers, the FMT is said to have lightning-fast transient response superior to dome tweeters.

MartinLogan Motion SLM

Another interesting aspect of the FMT is its controlled dispersion through horizontal and vertical ranges of 80 degrees. The advantage of this is that the SLM should sound the same whether placed horizontally or vertically -- which is beneficial for the timbral matching of all speakers in a surround-sound array. Another advantage is that it minimizes the off-axis sound, which is particularly useful for speakers mounted on walls, where wall bounce is a concern.

The cabinet of the Motion SLM is sealed -- no ports. To extend the speaker’s bass response, the modest 4” midrange-woofers use the air trapped in the enclosure as a spring to push the 4” passive radiators, effectively doubling the surface area devoted to reproducing the bass frequencies. The tweeter is crossed over to the woofers at 2600Hz.

The Motion SLM has a claimed sensitivity of 94dB/W/m, which should make it easy to drive to loud levels, and especially for modestly powered home-theater receivers.

Dynamo 700w subwoofer

As with the Motion SLM, MartinLogan has thought of everything for setting up the Dynamo 700w subwoofer ($695). It’s not only compatible with a wireless system, the transmitter is included at no cost. The 700w normally fires downward, but if you need to put it in a cabinet, the flick of a screwdriver converts it to a front-firer. A grille is included to cover the 10” driver. The sub’s tiny (1 cubic foot) cabinet is nicely finished in matte black.

MartinLogan Dynamo 700w

The Dynamo 700w is a sealed-box design: there are no ports or bass radiators to increase the sound pressure level. Its 10” polypropylene cone is driven by a 300W RMS (600W peak) amplifier. For a tiny subwoofer with high-performance aspirations, this design is outside the norm of a huge amp coupled to a high-excursion driver to play loud. For example, my Definitive Technology SuperCube II subwoofer is about the same size as the 700w, but its 8” woofer is driven by an amp claimed to output 1250W (most likely a peak power rating), augmented by two 8” passive radiators.

MartinLogan Dynamo 700w

The Dynamo 700w can be used with the LFE output from your A/V receiver, or the RCA stereo outs of a preamplifier or an integrated amplifier with preamp outputs. The controls are the same as on most subwoofers: Level, Low Pass Filter, Bypass, and Phase.


Because the Motion SLMs will primarily be used on walls, I set up two of them on my wall to either side of my 92” projection screen, their tweeters at around the height of my ears when I’m sitting down (43” above the floor). I placed the center-channel SLM below my screen, its tweeter 19” off the ground and tilted slightly upward for more direct, on-axis sound (but see below). All three speakers were approximately 13’ from my listening seat. Motion SLMs for the surround channels were placed on stands slightly higher than my ears, about 5’ away from my listening seat.

My Integra DHC-80.3 A/V processor includes Audyssey’s XT32 room-equalization software, which picked a subwoofer crossover of 150Hz. With the Motion SLM rated down to 110Hz, I reset the crossover frequency for all five speakers to 120Hz, so that more bass would come from the speakers and the subwoofer’s position would be less locatable.


Listening to the MartinLogan system, I was immediately aware that the Motion SLMs were not run-of-the-mill wall-mount speakers. The most notable trait was how deep the soundstage extended -- farther than any other on-wall speaker I’ve had in my system. Most wall speakers have adequate lateral imaging, but for depth, none that I’ve heard has been able to surpass freestanding speakers. The SLMs were as good as high-performing bookshelf speakers in this regard. The finger snaps in “Ode to Billy Joe,” from Patricia Barber’s Café Blue (SACD/CD, Mobile Fidelity Sound Lab B000063412), seemed to emanate from a point forward of the actual plane of the speakers, well into the room.

When I watched movies, the five Motion SLMs produced aural images with perfect timbral match. In chapter 1 of Hugo on Blu-ray, when the Station Inspector (Sacha Baron Cohen) and his dog chase Hugo, the dog’s barks moved through all of the channels with no change in sound quality. Other good examples were the ticking gears and moving trains in chapter 2, which maintained consistent tonal quality as they moved across the front channels and then to the surrounds. The ticking gears also highlighted a great trait of ML’s FMT: excellent transient response. I almost thought I was in an actual clock, so real was the ticking through the Motion SLMs.

MartinLogan Motion SLM

I noted that with higher voices, such as those of Hugo (Asa Butterfield) and Isabelle (Chloë Grace Moretz), the dialogue was clear and easily understood through the center-channel SLM. With lower-pitched voices, however, such as that of Georges Méliès (Ben Kingsley), there was a bit of cabinet resonance. This was easily corrected by tilting the speaker up a bit more than I’d initially had it. That done, I couldn’t hear the cabinet ringing unless I cranked the system to very high volumes. Comb filtering was virtually nonexistent when I listened to the center speaker while standing at the sides of my room.

Chapter 4 of Hugo revealed the remarkable 3D imaging abilities of the Motion SLMs. A train whistle to the right sounded as if it were well beyond the walls of my room. This is a remarkable feat for any speaker system, let alone one comprising wall-mounts. However, in chapter 8 of Hugo, in a scene in which papers fly around a room, rather than surrounding me, the sounds of the papers were confined to the locations of the direct-radiating SLMs. Watching this scene, I kept looking toward the speakers, which I don’t think was the response the surround engineer intended. Perhaps dipole or bipole speakers, such as MartinLogan’s own Motion FX, are better suited for these types of surround effects.MartinLogan wireless transmitter

The Dynamo 700w proved a perfect mate to the SLMs, and quite a bargain. I again used Audyssey XT32, which has higher-resolution filters for the subwoofer channel than 2EQ, resulting in more accurate correction. The blend of the outputs of the Motion SLMs and Dynamo 700w was perfect -- it would have been much harder to do this by ear, using test tones. The only annoying thing about the 700w is a blue light that constantly blinks when you don’t use the wireless kit or when it’s not in operation. If I owned a 700w, the first thing I’d do is put tape over this LED.

The Dynamo 700w was tight and accurate with any of the bass-heavy sound effects I could dig up on Blu-rays. In chapter 25 of Quantum of Solace, when a hydrogen canister explodes, the 700w slid across my floor! The 700w’s modestly rated amp had the jam to move that 10” driver like crazy. The bass was tight and solid, easily rattling fixtures in my room. In fact, the floor above my home-theater room was vibrating. Unlike other subwoofers in this price class, there was very little boom or overhang, just deep, solid bass. This little $695 sub performs well above its price -- all it needed was a strong set of spikes (they’re included) to stop it from moving clear across my room!


I own a set of speakers that are a good contrast to the MartinLogan Motion SLMs -- Angstrom’s Suono home-theater speaker system. I reviewed these wall-mounted speakers years ago, and still use them in my family room every day. This system, which retailed for around $1600 without subwoofer, consists of two main speakers, a center, and two surrounds. The Suono 300 S mains have an unusual configuration of two tweeters, one each at the top and bottom of the speaker, with two 4.5” midrange-woofers spaced equally between them. The Suono 200 S center has a conventional woofer-tweeter-woofer array, and the Suono 100 SD surround has a tweeter with two 4.5” midrange-woofers below it -- and two more tweeters, on the left and right side edges, for diffuse sound.

Compared to the less-than-2” depth of the Motion SLM, the Angstroms are pudgy, protruding about 3” from the wall. For those of you looking for Gangnam Style, no need to read on -- the slick SLM wins hands down in that department. However, the larger boxes of the Angstrom Suono system produce decent bass response without a subwoofer. When listening to jazz tracks such as “You Look Good to Me,” from the Oscar Peterson Trio’s We Get Requests (CD, PolyGram B0000047D5), which contains low notes from a double bass, I felt that a subwoofer was icing on the cake rather than a necessity. But with the Motion SLMs, I needed a sub to enjoy this track.

The Motion SLMs showed their superiority in high-frequency reproduction and depth of image. MartinLogan’s FMT is a marvel, with airy highs that shone when I listened to violins, as in Vivaldi’s The Four Seasons performed by Giovanni Antonini and Il Giardino Armonico (CD, Teldec 2 97671). In comparison, the Angstroms sounded polite and slightly dull. A great depth of soundstage was apparent with the SLMs, with the sounds of the violins free of the speaker locations. Through the Suonos, the violins fell back to the plane of the speakers, although the lateral imaging was the equal of the MartinLogans’.

I found the diffuse sound produced by the Suono 100 SD surrounds to be a better match with most movie soundtracks, though dialogue in the center channel was more intelligibly reproduced by the Motion SLMs. The politeness of the Angstroms’ tweeters made some voices harder to understand.

I no longer have the Angstrom subwoofer that was sent with the Suono system. However, I recently had in my system a sub of similar price to the Dynamo 700w: the PSB SubSeries 200 ($650). Although the PSB sub also has a 10” woofer, and a similar-size amplifier, the SubSeries 200 has a much larger enclosure (13.5” x 17.5” x 15.5”) and a large, downfiring port. The PSB played a bit louder, but MartinLogan’s Dynamo 700w sounded much tighter and performed better. The explosions throughout Quantum of Solace didn’t make the Dynamo 700w resonate through my room, as the SubSeries 200 did. I found the PSB sub fatiguing for extended listening periods because of this resonating sound. But I could easily listen to the Dynamo 700w all day long.

MartinLogan Dynamo 700wConclusions

Some MartinLogan fans would scoff at the Motion models -- they’re not big electrostats. But the Folded Motion Tweeter was designed to produce a transient response similar to that of the electrostatics ML is known for, and I think they’ve succeeded. I see it as a gateway speaker to the MartinLogan brand.

Although the Motion SLM system had some minor issues when compared to comparably priced freestanding speakers, it’s one of the best wall-mounted speakers I’ve reviewed. They’re beauties to look at, with a high-gloss finish to match that of any flat-panel TV. The Folded Motion Tweeter is more refined than those used in other wall-mounts I’ve heard, and the Motion SLMs produced much better depth of image than other on-walls -- at least comparable to that of good bookshelf speakers. Finally, if you’re looking for a small subwoofer, MartinLogan’s Dynamo 700w should be on your short list -- this little wunderkind slays anything in its class that I’ve heard. My review would not be complete without a mention of MartinLogan’s attention to detail: They provide everything you need to set up this home-theater system with ease. All in all, an easy recommendation.

. . . Vince Hanada

Associated Equipment

  • Preamplifier-processor -- Integra DHC-80.3
  • Amplifier -- Adcom GFA-7500
  • Integrated amplifier -- Bel Canto C5i
  • Sources -- Cambridge Audio Stream Magic 6, Oppo BDP-83 universal Blu-ray player
  • Cables -- Analysis Plus Blue Oval in-wall speaker cable, Analysis Plus Super Sub interconnects
  • Display device -- Sanyo PLV-Z5 projector with Grandview LFM-92 tab-tensioned motorized screen

MartinLogan Motion SLM On-Wall Loudspeakers and Dynamo 700w Subwoofer
System price: $3194.75 USD.
Warranty: Five years, speakers; three years, subwoofer.

MartinLogan, Ltd.
2101 Delaware St.
Lawrence, KS 66046

Phone: (785) 749-0133

Fax: (785) 749-5320