MartinLogan's Motion 4i ($249.95 each) is a diminutive, multi-purpose loudspeaker with something special that makes it more than capable of handling the right and left duties of a two channel, 2.1 channel, or even a surround sound system. This is audiophile quality loudspeaker at a very reasonable price. To get to what makes it special, though, we need to discover what MartinLogan as a brand is all about.
MartinLogan is celebrating its 35th anniversary in 2018. Gayle Martin Sanders met Ron Logan Sutherland at the high-end audio shop that Sanders managed in Lawrence, Kansas. Sutherland is a professional electrical engineer, while Sanders' background included architecture and advertising. What they had in common was a love of music and specifically electrostatic loudspeakers. It wasn't long before they built their own electrostatic speaker but the first versions, as legend tells the story, suffered from unsatisfactory high-frequency dispersion. The problem with the speaker was that the beam was too tight. The team solved the problem by using a horizontally curved panel resulting in the curvilinear line-source, which is the hallmark of every MartinLogan electrostatic loudspeaker built since then.
So, what is it about electrostatic speaker that made them worth the trouble? Electrostatics have very low distortion, for one thing, and are relatively resonance free across an extremely wide frequency range, offering a very musical overall experience. On the downside, they are inherently short on bass response, and so are almost always mated with a conventional woofer or powered subwoofer in a hybrid design.
Of course, there are other types of transducers that deliver many of the qualities for which electrostats are known, including planars and ribbons. Planars are very directional, which results in excellent imaging qualities. Ribbon speakers have extremely low mass and therefore respond to transients very quickly, making them very accurate, but they also tend to reveal any flaws of the recording and mastering process.
MartinLogan's Motion Series, on the other hand, employ an Air Motion Transformer very similar in design to that employed in the highly lauded ESS Series from the 1970s, and more recently in all of GoldenEar Technology's speaker. This design uses a folded ribbon tweeter, which achieves very similar results to the electrostatic principle, while allowing for a much smaller form factor.
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!
If you're familiar with MartinLogan's original Motion 4, released back in 2010, none of this is a revelation, of course. If you're new to the line, though, it's worth pointing out just how small this newly updated offering is. The MartinLogan Motion 4i is positively diminutive (by MartinLogan standards) at 13.1 inches high by 5.6 inches wide by 5.5 inches deep and a weigh of six pounds. It comes with removable grills and a clever mounting block that allows it to be mounted on a wall with the folded ribbon tweeter high-frequency devices aimed precisely where you like. It can also be simply placed on any flat surface, and is finished in a high-gloss black that was flawless on the samples I received for this review. The four-inch woofer is accompanied by a folded bass port, and while you will not get any significant low-frequency punch without adding a subwoofer, you will get extremely nice resolution in both the mids and the highs. Frequency response is reportedly 70 to 23,000 Hz with an 80-degree by 80-degree dispersion, sensitivity is rated at 90dB (2.83 volts/meter), and nominal impedance is rated at 4Ω (compatible with 4Ω, 6Ω, or 8Ω? amplifiers).
For those that may be wondering about the differences between the new Motion i update and the original Motion series, they are both aesthetic and sonic. As previously mentioned, the new Motion i series speakers now have removable grills. They also sport cleaner lines on the outside and tweaked crossovers within, designed for clearer and more well-defined upper mid to high frequency response.
The Dynamo series subs intended to complement the new Motion i lineup encompass several options, including the Dynamo 600X that was sent for evaluation along with the speakers. While I did compare the 4i with and without the sub, this review focuses predominantly on the 4i's capabilities on its own. If you are building a surround sound system, MartinLogan offer the Motion 6i ($279.95 each) and Motion 8i ($399.95 each) center channel speakers. The 4i can be used for rear surrounds as well as front left and right, or you could go even smaller and use the Motion 2i for surrounds, if you wish, depending on room size.
I auditioned the Motion 4i separately with both my Glow Audio Amp Two tube amplifier, as well as my SMSL AD18 Class D amplifier using my MacBook Pro as a FLAC file music server, alternating between the internal DAC and the DAC built into the SMSL amp. All interconnects are by Kimber. I almost always have a clear preference for the tube amp, but with the Motion 4i I honestly have to say there were times when I preferred the more neutral sound of the Class D amp and times when the tube warmth won out depending on the piece of music.
Click over to Page Two for Performance, The Downside, Comparison & Competion, and Conclusion...
I first situated the speakers at ear height, roughly six feet apart with a 60-degree angle toward my central listening position, which is about nine feet away. After a few tracks I experimented with moving them closer to the rear wall and therefore moving my chair a bit towards them to maintain the same distance. This made a very big improvement, so keep this in mind when you position the 4i: it likes a good bit of boundary reinforcement. I imagine most will be either mounting these directly on a wall anyway, but if surface mounting on a flat surface, you may want to pay attention to the differences even a few inches can make relative to the wall and adjust accordingly. Now that I had the speakers dialed in, I moved on to several tracks that I imagined would push these 4i to its limit, starting with Chuck Berry's "You Never Can Tell" off the Pulp Fiction soundtrack. That track is replete with high register piano pounding, a full horn section, and a crack snare that tests the high frequency transient response and mid frequency resolution of any top performing speaker. The result? The 4i was crystal clear, with no lack of clarity in the midrange frequencies that I could hear.
Next, I cued up Haydn's "Emperor's Hymn from String Quartet in C." I chose this piece because of the delicate interplay between the strings and very little low frequency information. The 4is were silky smooth and brought forward all the detail and complexity without any comb filtering or coloration.
Moving on in a completely different direction, I wanted to hear how the 4is handled female vocals. After listening to a few of my favorites, I settled in with Diana Kralls' version of "California Dreamin'." This track has some very nice reverb trails and space in the mix to let them roll off into the distance. The 4is sounded crisp yet rich, but by now I knew the 4is could handle more spacious mixes like Shawn Mendes "In My Blood." Check out the chorus, the first instance of which hits at the 1:10 mark, where it gets a bit dense. The Motion 4is grappled with the thick mids and bottom-heavy beats and were able to maintain the utmost clarity without losing emotion.
But what if you want to use these in a home theater configuration for watching movies and television? I rearranged my home theater to substitute the left and right channels of my Dolby Atmos system, placing them as close as possible to the same position as my Definitive Technologies DI 6.5 LCR in-walls. I am not going to tell you they entirely kept pace with the DefTechs, largely to size and timbre matching with the rest of my system but they sounded very good. Good enough that were they mated to their own surround sound brethren, I can imagine the system being extremely good, and due to their ingenious mounting hardware and design, they offer a terrific option for on-wall if you don't want to cut holes for in-walls.
I binge-watched a few episodes of Stranger Things on Netflix and then Speilberg's Ready Player One, and between these selections there was plenty of hard left-right panning and off-screen dialogue, and with the Dynamo 600X sub, I could tell these would make for a great 2.1 or surround sound system that would complement a very, very nice (and affordable) home theater.
The Motion 4i is ported to the rear, and as such its low frequency response fluctuates pretty substantially as you move it toward and away from the wall behind it. That is true of all rear ported loudspeakers, but vastly so here. With tabletop placement that might not be a big concern, but if you're mounting them on a wall, well, you can't make any adjustments, except via bass management or room correction.
Comparison and Competition
The ELAC Uni-Fi UB5 ($500 per pair) are a bit larger and there are fewer factory wall mount options, not to mention the fact that they sport nothing like MartinLogan's unique Motion Series aesthetic. The ELAC is a three-way system, though, employing conventional dome/cone transducers and sound very nice. You won't get the sonic signature of a folded tweeter, but if you aren't planning on adding a subwoofer, the UB5s would make a good choice as they offer a bit more bottom right out of the box.
KEF's Q100 ($549.99 per pair) is much wider and deeper, and again doesn't come packaged with wall mounts. The Q100 is a two-way concentric point-source design also employing conventional dome/cone transducers, this time with afront firing port, though, so it will be less dependent on placement proximity to a wall to optimize bass frequency response. As with the ELAC, the KEF is a conventional boxy bookshelf, though.
More suitable competition comes in the form of GoldenEar Technology's SuperSat 3, which is pretty close in size, relies on quite similar driver technology, and checks in at roughly the same price as the Motion 4i. The GoldenEar is a sealed design, so placement isn't quite as finicky, although of course that means that its bass extension isn't quite as low. It is a few dB more sensitive, though.
One other thing that sets the Motion 4i apart is that it's individually priced, not lumped in pairs. At any rate, buy them in twos or fours as most people probably will, and you're looking at a cost of $499 per pair. Add the MartinLogan Dynamo 600X to the mix and you're looking at an additional $600, for a complete 2.1 speaker system cost of right at $1,100 (probably closer to $1,000 by the time you get to street pricing). You can obviously spend more and get more sound overall, but at this size, MartinLogan doesn't have a substantial amount of competition.
Considering size, cost, and design, the MartinLogan Monitor 4i is hard to beat. The sonic signature of a folded tweeter sounds great to my ears, and lends a very open and detailed musicality to everything you might throw at it in a variety of systems and speaker configurations.
• Visit the MartinLogan website for more product informtion.
• Check out our Bookshelf Speaker Reviews category page to read similar reviews.
•MartinLogan Announces Next Generation of Dynamo Subs at HomeTheaterReview.com.