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    $249 MartinLogan Motion 4i Review

    I've been a dipole speaker enthusiast for many years. I suspect that I've owned as many as 7 pairs of Magnepan speakers over the years including the outrageous Tympani IIICs with their 8 panels. A number of years ago, I reviewed a pair of MartinLogan Aeon-i electrostatic speakers and never looked back. I purchased the review samples and still have them.  So happy have I been with the M-L speakers, which have never given me a moment's trouble or regrets in all the years I've owned them that when I got the chance to review the company's small Motion 4i speakers, I jumped at the chance.

     

     

    Motion 4i Description

     

    33723728125_3b8d993ebd_b.jpgThese small speakers are designed to set on a pair of stands, or perhaps a bookshelf or, in my case a desktop. These speakers are 12.6" x 5.6" x 5.7 (32cm x 14.3cm x 14.5cm) and weigh 6 pounds or 2.72 Kg each.  The front of these tall, narrow, piano-black speakers is straight with a metal grille held on the front of the cabinet by magnets. From the rear, the cabinets are curved in a concave fashion and are ported with a Helmholtz resonator. Also on the back is a captive threaded sleeve for mounting on a wall with the included wall mount plate.

     

    The Motion 4i is a fairly straightforward small speaker with a 4-inch “woofer” giving response to 70 Hz ± 3dB. The system crosses over to the tweeter, which is absolutely most interesting feature of this speaker system at 2900 Hz. The 4i has what M-L calls a Folded Motion Transducer of 5.25” X 1.75” (2.6cm X 3.6cm). This tweeter is, in reality, an adaptation of the famous Heil Air motion Transformer first invented by engineer Oscar Heil at ESS Systems, Inc. This transducer works very differently from a normal cone or domed tweeter in that it works like an accordion in that the “diaphragm” is pleated and works by squeezing air out from between the pleats as they compress together and expand at an audio rate. The advantage of this system is that it is very low in distortion and doesn't have the modal breakup that often plagues normal apex driven piston-like tweeters. The result is a small system with a frequency response of 70 to 23,000 Hz ±3dB. Interestingly this is almost identical to the frequency response of the famed BBC/Rogers LS3/5a. Sure, the top end of the M-L goes a tad higher, but the main difference is that no LS3/5 from any company licensed to make it has a tweeter as good as that of the Motion 4i!


    When seen with the metal grill removed, one will notice, that below the woofer, there is a strange looking plastic disc poking through the cabinet. This is not another driver, but is, in reality, the back of the unique Helmholtz radiator and allows the resonator to act as a semi-folded horn. Behind that plastic disc, the low frequencies make a 180 degree turn on their way out of the box. I've never seen a Helmholtz resonator that worked this way in any other speaker.  

     

     

    Power Requirements

     

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    MartinLogan recommends powering the 4-Ohm Motion 4i with between 20 and 150 WPC. I use a Napa Acoustics NA208A hybrid tube/solid-state integrated amplifier of 25 Watts/channel and this seems to be plenty for these speakers (I don’t know whether or not the Napa amp doubles its power at 4 Ohms as opposed to eight Ohms.). The amp is sourced from China by the San Francisco Bay Area Company Napa Acoustics and though small,  it performs admirably for its size, cost and power. It has vanishingly low distortion and very flat frequency response.  The amp is connected to the Motion 4i speakers with Sewell Direct's excellent “Silverback” 12 Ga 6 ft speaker cables terminated in very high quality banana plugs (http://tinyurl.com/yxmvbj9t). The Motion 4is have unique banana jacks which are mounted flush with the back panel and “grab” the plug when inserted. There is no provision for spade lugs but for bare wires the spring loaded binding posts, when pressed, open up a hole through which the wire can be inserted. The channels above and below the posts serve as a guide to help slide wire into the hole.  

     

     

     

     

     

     

     

    The Sound: Bass

     

    It should be apparent from the specs that these speakers aren't great shakes in the bass department. Being 3 dB down at 70 Hz and 6 dB down at 60 Hz tells us that the low frequencies drop like a stone below 70 Hz. However, this is somewhat misleading. The bass on these speakers is very well defined and very well controlled. Low frequency transients are fast with little or no hangover. When playing something like Saint-Saens' Symphony #3, “The Organ Symphony” (Reference Recordings (RR-136), the organ comes through loud and clear. While not very deep, the bass is taut and clean and in the final analysis quite satisfying, especially for a desktop computer speaker. But if you are a bass freak, I'd suggest you augment these speakers with a good pair of subwoofers or go another route. 

     

     

    The Sound: Midrange and Tweeter

     

    AS Mentioned earlier, the glory of this speaker system is the Folded Motion Transducer tweeter. Starting at just below 3KHz, this tweeter is simply amazing. It reminds me so much of MartinLogan's electrostatic “house sound” that it's uncanny. As I write this I'm listening to Jascha Heifetz playing the Rozsa Violin Concerto (Miklos Rozsa wrote this superb concerto especially for Heifetz in 1956). This recording was made in that same year for RCA Victor in the “golden era” of stereo. It sounds magnificent and images like gangbusters because, like all early RCA Victor Living Stereo recordings, it was made with a minimal microphone technique of two or three microphones only. Heifetz’ violin, a 1714 “Dolphin" Stradivarius, heard through these speakers is uncanny and sublime. It sounds so clean and articulate, that I must credit the M-L's tweeter for this superb high-frequency performance. The orchestral background with Walter Hendl and the Dallas Symphony is simply gorgeous with these speakers, each instrument is in its proper place and size. The sound is simply sublime and it just sings via the Folded Motion Transducer on the MartinLogan Motion 4i speakers.

     

     

    Conclusion

     

    These speakers are moderately priced at US$249.99/ea and would be the least expensive speakers on the market to sport an air motion transformer type tweeter, if it wasn't for the little bother Motion 2i at $179/ea. For that reason, they are bargains that punch quite a bit above their weight. If you are looking for a really good, affordable pair of speakers for the desktop, the vacation cabin, or for a small stereo system in a dorm room or small apartment, I haven't heard anything that comes even close to sound quality of the MartinLogan Motion 4i at anywhere near their price poiint. I would say that except for that last octave of  bottom-end, that these modest speakers are pretty much perfect for their intended application. That they beg comparison with the latest incarnation of the BBC/Falcon Audio's LS3/5a (US$2995/pair) is just gravy. Believe me the MartinLogans sound quite a bit better than this famous Brit from “Auntie Beeb*”. I once worked for a radio station that used the Rogers version of the LS3/5a as studio monitors, so I'm quite familiar with them.


    However, if you are bass freak, you're gonna need to add subwoofers or try another speaker. MartinLogan has an entire line up of the Motion series of speakers at all price-points up to around $3000. All of these use the Folded Motion Transducer tweeter and have the same effortless top end that the Motion 4i's exhibit. Of course the bigger speakers have more bass and all sound superb. I hesitate to recommend the top-of-the-line Motion 60XT because of its price (US$2999.95/). For that money, one can buy a pair of MartinLogan's ElectroMotion electrostatic hybrid speakers, and I have friends who own these and I think they are a better buy for less money. Besides the US$500.00 difference between the 60XT and ElectroMotions can buy an awful lot of music! The Motion 4i is highly recommended and might just be the most articulate small speaker one can buy for the money. 

     

    * “Auntie Beeb” is the nickname that the British gave their beloved BBC many decades ago, and it has stuck. 

     

     


    Product Information:

    MartinLogan Motion 4i ($249)
    NDH20 Product Page (link)
    Product Brochure (PDF)
    User's Manual (PDF)

     


     



    User Feedback

    Recommended Comments



    6 hours ago, gmgraves said:

    Of course the MMG and the Point Sevens are better, overall, but neither work very well as desktop speakers,  or speakers for small bookshelf systems, which was the point of the review, I suspect. The MMG is, in my opinion, probably the best speakers under $1k that there are, but they require a lot of power as do the Point Sevens.

    I thought that the MiniMaggies were the worst Maggie’s I’ve heard, especially for the price. But the Motion 4i is 70 - 23,000 +/- 3dB. That’s pretty flat over the speaker’s range. 

     

    For some reason, I thought they were flat only to 90hz. That makes a difference!

     

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    Yes, if it gets down to 60, 70Hz all's good ... what usually happens with cheaper speakers is that they hook it up to a gutless amplifier; which falls into a heap when asked to deliver solid bass energy - "Must be the speaker", they say ...

     

    You could shock a few people by grabbing a tiny, lightweight speaker, mass loading it solidly, and driving it with a Krell-like amp ... "Where dat bass come from?!!", would be the exclamation.

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    On 7/3/2019 at 2:06 PM, k-man said:

    Any other amps out there that also "deliver the audiophile-like experience without the audiophile price"?

     

    Actually I just meant to ask anything that will pair well with these 4i's for no more than $400? 

    I think the Napa Acoustics 208A is $399 (at least it used to be. Their website is blank right now!). But if you go on alibaba.com you can get that same 25 WPC hybrid amp (dual triode front end, solid-state output) directly from China for far less than Napa sells it for.

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    I have a 5.1 system with 4 of these, a matching center, and an (ancient) M+K sub.  Sounds wonderful :)

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    On 7/3/2019 at 10:47 PM, fas42 said:

    Perhaps surprising to many people what 15 watts can do - the Philips HT all in one only used 15W chip amps, with nothing special specs; the speakers were nothing special in sensitivity. But the system could still do realistic sound level piano pieces, mainly because the system held together at max gain. Also helped by having a separate, powered subwoofer.

     

    On a modern, compressed recording the SPLs were intense enough to cause ringing in the ears after 5 mins or so ...

    Why would this be surprising to anyone who understands how power works- especially if a subwoofer is involved? IME for that matter, ringing ears is often a byproduct of distortion, and not something to get excited about. Then again, it seems pretty clear that you likely have never heard beyond a middling system or you'd not make these crazy proclamations.

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    On 7/4/2019 at 12:38 AM, Paul R said:

     

    Not a chance Frank. Lack of energy below say, 110hz generally makes for terrible sound with many different kinds of music. At any volume level. 

     

    Well, maybe it can improve rap.

     

     

    Broken, non-functioning amplifiers are the only thing that can improve rap

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    On 7/5/2019 at 4:42 PM, jhwalker said:

    I have a 5.1 system with 4 of these, a matching center, and an (ancient) M+K sub.  Sounds wonderful :)

    Four of what, the Motion 4i speakers or the Napa Acoustic 208A amp? 

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    On 7/5/2019 at 5:42 PM, jhwalker said:

    I have a 5.1 system with 4 of these, a matching center, and an (ancient) M+K sub.  Sounds wonderful :)

     

    Those old M&K subs are absolutely bomb proof!  I have a M&K VX-100 in my home theatre set up that has been powered on and running almost continuously (I bet it has only been turned on and off less than 5 times?) for about 20 years.

     

    What a great investment.  Nice, tight bass as well.

     

    Back to desktop speakers, I just picked up these Scansonic MK-5's.  Seemed like a great price.  We shall see how they perform.

     

    https://www.underwoodhifi.com/products/scansonic

     

     

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