MartinLogan Motion 4i Bookshelf Speaker Reviewed

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MartinLogan Motion 4i Bookshelf Speaker Reviewed

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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_Motion_4i._tweeterjpg.jpgMartinLogan'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!

MartinLogan_Motion_4i_iso.jpgIf 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 4, 6, 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.

The Hookup
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...

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