Review: Martin Logan Motion SLM X3 – Clarity is the key

There’s a lot more to this ultra-slim passive soundbar than meets the eye. While it’s a compact and classy alternative to conventional left/centre/right speakers, the Motion SLM X3 also makes the most of musical fare.

By Deon Schoeman

Soundbars come a variety of sizes, flavours and executions.

Some are active, and include video switching as well as digital signal processing and room correction. Others adopt a more straightforward, passive approach while focussing on enclosure design and driver performance.

Soundbars are usually associated with home theatre applications, where they are mostly used in lieu of conventional front left and right, and centre speakers – either because there’s no space for multiple speakers, or because the customer prefers the uncluttered elegance of a soundbar.

Soundbars also come into play as replacements for TV sound – in other words, as a way to upgrade the often tinny and poorly projected sound of a television set’s own loudspeakers.


Martin Logan’s Motion SLM X3 fits into the passive soundbar category. No, it doesn’t have its own amplification. And no, there’s no DSP involved.

But it is a sleek, slim and attractive soundbar – and under the covers, there’s plenty of sophistication. That’s not surprising, considering the Martin Logan brand’s heritage as a producer of high-end, innovative loudspeakers.

At around 1,2 metres, the SLM X3 isn’t exactly small. But because it is so slim and sleek (it’s only 51 mm thick) it’s both elegant and unobtrusive. A perforated metal grille and gloss-black enclosure add to the unit’s visual appeal.

The soundbar can be wall-mounted, or located on a shelf, with mounting hardware for both provided. If positioned on a shelf, the tilt angle can also be adjusted.

Being passive, there are no inputs or power receptacles. However, the rear panel does host three sets of spring-loaded, push-down speaker terminals, marked left, right and centre – confirming the SLM X3 L/C/R role.

The binding posts are nicely turned out, all-metal affairs (not those cheap and nasty plastic devices you see on equally cheap and nasty speakers), and will speaker cabling of up to 14 gauge.


Lurking behind the grille are no less than nine drivers, arranged in sets of three. Each set consists of a tweeter and two midrange drivers.

The tweeters aren’t your average soft-dome designs, but Martin Logan’s Folded Motion transducers. A folded diaphragm is used to squeeze the air much like the way an accordion does when in response to a powerful magnetic field.

The benefits of this design, which I assume is based on the Heil Air Motion Transformer, is high efficiency, thanks to the low mass and folded diaphragm, coupled to powerful neodymium iron boron rare-earth magnets.

The SLM X3 gets three Folded Motion transducers – one each for the left, right and centre channels. Each tweeter is partnered by two paper-coned midrange drivers.

For the left and right channels, the tweeters are at the extreme ends of the bar, followed by the two midrange drivers. The centre channel HF transducer is centred, with a midrange on either side.

As the soundbar has been designed to be used in conjunction with a standalone subwoofer, its low-frequency output is limited to 120 Hz, but at the high-frequency end, response extends to 23 kHz.


I hooked up the Motion SLM X3 to our Yamaha RX-A3080 AV receiver, while our regular Atlantic Technology subwoofer remained on duty.

The soundbar was evaluated both with and without the Atlantic Technology surround and surround back speakers installed in our listening room. However, I think that by definition, soundbar users don’t have the space or the inclination to use surround speakers.

I made a point of using the bar in stereo role, too: again, I’m pretty sure many users will expect the SLM X3 to fulfil both movie and music duties.


Given the Martin Logan pedigree, you’d expect a classy sonic delivery and that’s exactly what you get: an open, airy and expansive sound that always seems bigger than the dimensions and limitations of soundbar would suggest.

As mentioned, it doesn’t try and reach below 120 Hz, but excels in the mid and high bands with a sleek, clean and accessible delivery that is adept at capturing and projecting detail, while creating a wide and open soundstage.

Directional and dimensional representation was pretty good for a soundbar: imaging was finely focussed, with plenty of width and height to create a spacious, believable sonic image. The ability to harvest and accurately present fine details assisted in creating a strong sense of realism and believability.

Incorporated in a surround system, the font staging tended to shine, and generally outclassed our conventional surround and surround back speakers: clearly it would be ideal to partner the bar with SLM surrounds to ensure seamless voicing.

That said, the real appeal of a soundbar such as this lies in its ability to obviate the need for surrounds, and so this ends up being a 3.1 solution, with surprisingly enjoyable results.

Predictably, dialogue projection was excellent, with the SLM X3’s inherent clarity and resolution really coming to the fore.

Of course, surround effects aren’t as three-dimensionally projected as would be the case in a multispeaker surround set-up, but due to the bar’s ability to afford the sound ample space, the result is still surprisingly engaging and believable.

The Martin Logan also acquitted itself well with stereo fare, where its talents for focussed imaging and wide-open staging were spotlighted.

You forget that you’re listening to a soundbar, as the music doesn’t appear to be limited in spatial or terms: it casts the sound wide, high and deep enough to make for compelling listening.

Again, it was the SLM X3’s talent for unravelling complex passages and highlighting fine details and nuances that set it apart from lesser designs, together with an inherent clarity that made conventional 5.1 systems sound veiled and just a little indifferent.

With those relatively small mids and superfast ribbon tweeters, there was never any shortage of pace and precision, adding to the speaker’s talent for insight and realism.


The Motion SLM X3 is not for everyone. It’s not active, and offers no DSP-driven simulated surround. Instead, its talents are rooted in its clarity and honesty, its ability to reveal and resolve detail all too easily glossed over, and its three-dimensional imaging, which is a believable alternative to decoded surround.

Put it this way: when you’re listening to music, or watching movies, wit the Martin Logan in charge, you don’t analyse how realistic the surround sound is, or whether the effects are impressive enough. Instead, you simply sit back and enjoy.

The SLM X3’s superb centre channel capabilities allow it to deliver peerlessly projected dialogue, and with surround material, the expressive dimensionality still allows for an enjoyable movie experience.

However, it also excels in a stereo role, and will please music lovers with its finely imaged, generously presented performance.

A final caveat, though: the Motion SLM X3 deserves to be paired with a decent subwoofer, and equally high-standard amplification and source ancillaries, to demonstrate its full potential.


Enclosure type: Horizontal soundbar, sealed
Drive units:
Three 26×36 mm Folded Motion Transducers
Six 102 mm paper cone midrange drivers
Bi-wiring: No
Impedance: 4 ohms
Sensitivity: 93 dB @ 2,83V/m
Frequency response: 120 Hz – 23 kHz, ±3 dB
Power handling: 70 watts
Dimensions (WxHxD): 1 220 x 162 x 51 mm
Weight: 5,9 kg
R17 395
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