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    MartinLogan Motion 40i Review

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    MartinLogan Floor Standing Speakers

     

    MartinLogan is an American speaker manufacturer (although its main factory is in Canada) long known for its hybrid electrostatic/cone loudspeakers. Readers will remember that several months ago this reviewer wrote about the company’s bookshelf Motion™ 4i speakers. The Motion series is a departure from MartinLogan’s traditional offerings in that this line of speakers does not utilize electrostatic drivers. Instead, the Motion series is a cone-based speaker system that employs Oskar Heil’s “Air Motion Transformer” (AMT) technology for it’s high-frequency driver unit. The AMT differs from conventional tweeters in that instead of using a piston-like diaphragm the way most magnetic tweeters operate, this technology works similarly to the way an accordion functions. In an accordion, when one squeezes the bellows together the space between the pleats goes away. When one pulls the bellows back apart, those spaces re-appear. If you place your hand close to the accordion’s bellows while someone is playing it, you will feel a rush of air as the accordion is squeezed together. The compressing pleats push air out from between the pleats as that space is eliminated by the compression. Of course, the same thing is occurring inside the bellows as well and that out-rush of air is what powers the instrument and vibrates the various reeds to play the notes. 

     

    AMT-motion-40i.jpgThe AMT works on that principle. The diaphragm in the tweeter consists of a pleated Polyamide sheet arranged so that the pleated area is facing the listener. The electromagnetic “motor” is arranged so that instead of moving a disc-shaped diaphragm in and out like a normal speaker driver, this one squeezes the pleats in a manner that is perpendicular (rather than parallel to) the desired air displacement. When the pleats are squeezed together, on one half of their cycle, they compress the air between each fold, displacing it and when the pleats expand again, on the other half of the cycle, they rarefy the air as it rushes in to refill the voids between each fold. When they do that at an audio rate, sound is produced. Dr. Heil invented this concept in the early 1970’s and applied it a line of speakers built by the firm of ESS in South El Monte, California. While ESS still makes speakers employing this technology (down to around 800 Hz), the patents have expired and many companies now build variations on this theme. Searching on the Parts Express web-site, I see that they carry a number of AMT tweeters ranging in price from about US$20 each to US$120 each. Judging by the number of speaker companies both in the USA and in Europe who utilize AMT tweeters, I’d say that the technology has become quite popular of late.

     

     

    The Motion 40i

     

    MartinLogan makes an entire line of loudspeakers employing the AMT tweeter, and they range in price and size from the Motion 2i, a small bookshelf model starting at $US200 each all the way up to the large floor standing “flagship” 60XTi at US$1750 each. For this review, we are interested in the next to the largest floor stander, the Motion 40i. 

     

    The Motion 40i is a tall, narrow “tower” speaker of the type so popular these days. Measuring 42.5" x 7.6" X 12.8"(107.9cm X 19.2cmX 32.6cm), it consists of two woofers in the bottom part of the cabinet and a midrange and tweeter in the top. There is a decorative strip between the lower part of the cabinet containing the two 6.5”(16.5cm) woofers and the upper part of the cabinet containing the single 5.5”(14cm) midrange unit and the 1.25 X 2.4”(3.2 X 6.1cm) AMT tweeter. A metal decorative strip separates the two fabric covered plastic grills, each of which is separately removable and held in place magnetically. With the top grill removed, the speaker looks like a typical small bookshelf or desktop speaker with the low frequency driver topped with the tweeter. The cabinet on the review sample is finished in very high quality red walnut wood and is available also in a gloss black or a matte white cabinet. On the back are four of the well-regarded MartinLogan proprietary “wing-nut” shaped, tool-less hand tightened 5-way binding posts capable of handling bare wires, spade lugs or banana plugs. Each pair of the four connection are strapped together but are separable via metal straps for bi-amping, (or bi-wiring if one believes in such a thing). At the bottom of the cabinet is a Helmholtz resonator (a round -in this case- bass-reflex port with an internal pipe connected to it). Each cabinet weighs 49 pounds (22.2Kg). There are no controls on the speakers, but the user has the choice of either spikes or flat pads which screw into the bottom of the cabinets at the four corners. For this review, the spikes were employed to pierce the carpet and make contact with the concrete slab floor. The Motion 40i retails for US$1199.99 each.

     

     

    Specifications

     

    Motion-2_Binding-2-posts.jpgThe MartinLogan Motion 40i speakers are rated at 40 to 25KHz ±3dB and are recommended to be used with amplifiers ranging from 20 to 300 Watts/channel and have a sensitivity of 92dB/2.83volts/meter. This three-way system crosses over to the midrange at 500 Hz and to the AMT tweeter at a surprisingly low 2600 Hz. Both the 5.5” midrange and the two 6.5” woofers have an aluminum cone in a non-symmetrical chamber format and a cast polymer basket with a rigid, structured dust cap to reduce cone breakup and any modal resonances. The crossover is a Precision Vojtko™ design sporting custom air core coils and low DCR (DC Resistance) steel laminate inductors. Polyester film capacitors are wired in series and low Dissipation Factor (DF) electrolytic capacitors are employed in parallel to maintain phase integrity. The Motion 40i speakers have a nominal impedance of 4Ω and are compatible with all solid state and most tube (valve) amplifiers as well.

     

     

    The Sound of The Motion 40i

     

    48578150567_0482e1400f_b.jpgIf you go back to July 2, 2019, you will find that this writer favorably reviewed a pair of the MartinLogan Motion 4i, and small, compact bookshelf/desktop speaker. The major point of my review was the AMT tweeter used in this diminutive speaker. The same technology is evident here in the 40i. The AMT used in this speaker is identical in size. It crosses over at a slightly lower frequency but the result is the same – effortless ESL-like upper midrange clarity and high frequency extension. 

     

    When I unboxed the 40i’s for the first time, I was rather disappointed. I was replacing my beloved MartinLogan Aeon-i electrostatic hybrid speakers with these and found them thin and forward in the midrange with a slightly nasal quality. This was confusing because the note on the packing slip told whoever was in charge of dispatching these speakers to me to be sure to see that they were run-in for 100 hours and inspected before they were sent out. It seemed to me that 100 hours of run-in should be more than adequate to insure that, out of the box, these speakers would perform at their optimum. A phone conversation with Devin Zell of MartinLogan assured me that whatever run-in these speakers received at the factory, they undoubtedly needed more.

     

    I played them more or less continuously over the next week (using the 192 kb/second MP3 Internet feed from WCRB Boston). Every time I sat down to listen I noticed an improvement. The first thing I noticed was that the nasal quality rather quickly disappeared. Next, the bass improved by leaps and bounds and the speakers’ overall balance became more neutral. Soon I was marveling at how good these speakers actually sounded! The new album by John Williams conducting the Recording Arts Orchestra of Los Angeles with Anne-Sophie Mutter, violinist,  of  Williams film music: “Across the Stars” has a cut called Rey’s Theme from “Star Wars: The Force Awakens”. This piece has a bass line that is truly spectacular. On good headphones, the string bass is truly realistic and totally natural sounding. With the 40i’s, the bass is deep and relatively well controlled for reflex bass. I have no doubt that these speakers have usable bass response down into the mid-thirties but, bass reflex designs, to me, have always been a bit wooly and these speakers are no exception. While my Aeon-i’s are likewise a bass reflex design, the bass seems to be a bit better controlled than that of the Motion 40i speakers. That’s not to say that the bass on these speakers is not satisfying, it is quite so, and gives the speakers a fulsomeness that is addictive to say the least in spite of not being as neutral as some. 

     

    Going up the spectrum the aluminum coned midrange is clean and well balanced. Vocals come across with just the right amount of weight and articulation. Astrud Gilberto’s vocal on The Girl From Ipanema from the “Getz/Gilberto” album on Verve (Catalog Number 80020749-02) has just the right balance with the guitar of her husband and Stan Getz’ tenor Saxophone has never sounded better. Back to Anne-Sophie Mutter’s violin on the Williams film soundtrack album, it is as sweet as a mother’s kiss with soaring highs and resinous bowing that sounds utterly realistic. The AMT tweeter is still the star of this show. On my own recording with the “San Jose California Symphony Orchestra” under Georg Cleve of Ravel’s Daphnis et Chloe ballet, the triangle floating over the left side of the orchestra has a clarity and an other-worldly etherial quality that I have rarely heard on a speaker. It’s even better than on my Aeon-i electrostatics! Imaging on this speaker, is almost uncanny. Again, it is the AMT that does the honors. Still listening to my own recordings, made with a pair of Sony C37P FET microphones mounted on a stereo T-bar about 8 inches apart at a 45° angle to each other and about 10 feet over the conductor’s head and slightly behind him, the listener can close his eyes and point to every instrument in the ensemble. One can tell that, for instance, the brass is behind the woodwinds (and slightly higher in elevation) and the woodwinds are behind the violas and cellos. This pinpoint image specificity and wide, deep soundstage is, as far as I’m concerned, the only justification needed to recommend true stereo miking on acoustic music recordings! The MartinLogan Motion 40i’s point out this incredible soundstage performance better than any floor standing cone-based speakers that this writer has heard in a long time.

     

    Conclusion

     

    The MartinLogan Motion 40i speakers are an affordable entry into a truly full range high-end speaker system. With it’s combination of usable, fairly well controlled bass down into the mid-30’s coupled with a low-distortion midrange driver, and an exemplary Air Motion Transformer tweeter, it’s hard to find a better pair of floor standing speakers for under US$2500.00. One could, contemplate the ElectroMotion ESLs for about the same price, but I have friends who have these speakers and as good as they are, in my opinion, the Motion 40i’s are a better value. If you are in the market for a new pair of floor-standing, small footprint, full-range speakers, put these on your short-list and try to give them a good, hard listen. If you are worried about the WAF (Wife Acceptance Factor) take the lovely lady along with you and show her the red walnut finished cabinets. That might just cinch the deal. They’re that pretty and surprisingly inconspicuous!

     

     

     

    Product Information:

     

    MartinLogan Motion 40i ($2399.98 /pair)
    Motion 40i Product Page (link)
    Product Brochure (PDF 6MB)
    User's Manual (PDF 3.4MB)

    Dimension Drawings (ZIP 2.3MB)

     

     

     

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    User Feedback

    Recommended Comments

    1 hour ago, The Computer Audiophile said:

    Hi George - Thanks for the review. Very concise. 

     

    I have a soft spot for MartinLogan and I'm always interested in its speakers. ReQuests were one of my first real high end speakers and I'll never forget that sound :~)

     

    Same here...passed them on to a family member and he is absolutely thrilled with the Requests. They still sound great and Dirac Live takes care of any room issues.

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    > "bi-wiring if one believes in such a thing"

     

    Have you ever tried bi-wiring? It made a significant and easily noticeable difference in the two pairs of speakers I tried it on. The sound also changed when I single-wired with jumpers on the tweeters vs. jumpers on the woofers.

     

    Martin Logan speakers would definitely rate a look if I were shopping. The price is reasonable and the AMT tweeter is an amazing device. Quite a few designs used an AMT at the Toronto audio fest. I'm not a fan of ported speakers either. I would want to block the ports and cross over to my subs.

     

    I am not a fan of previous ML speakers. Crystalline highs but no body. 

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    On 12/20/2019 at 8:02 PM, audiobomber said:

    > "bi-wiring if one believes in such a thing"

     

    Have you ever tried bi-wiring? It made a significant and easily noticeable difference in the two pairs of speakers I tried it on. The sound also changed when I single-wired with jumpers on the tweeters vs. jumpers on the woofers.

     

    Martin Logan speakers would definitely rate a look if I were shopping. The price is reasonable and the AMT tweeter is an amazing device. Quite a few designs used an AMT at the Toronto audio fest. I'm not a fan of ported speakers either. I would want to block the ports and cross over to my subs.

     

    I am not a fan of previous ML speakers. Crystalline highs but no body. 

    Bi-wiring doesn’t really do anything positive. As far as cable is concerned, it’s like upping the gauge to the wire, but if you are splitting the woofer and tweeter by removing the shorting straps at the speakers and connecting them back together at the amplifier, all you are really doing is moving the place where the woofer and tweeter are joined from the back of the speaker with just a very short, low-resistance strap to a long, higher resistance cable. Sure it can change the sound, but I assure you it is subtracting something rather than adding anything. If you like that better, well, that’s up to you. But you really should know what’s actually going on. Also, while we’re on the subject, bi-amping a speaker that won’t let you bypass the built-in cross-overs, is also, mostly futile. For proper bi-amp performance you want a small signal crossover BEFORE the amplifiers. Now you’ve got the true advantages afforded by bi-amping! There is an exception to that. Even if you are stuck with the speaker’s built-in crossover, you will still get benefit if, for instance the two amplifiers you are using have vastly different sonic signatures. For instance, if you prefer the bass of a solid-state amp, you might want to put that on the woofer, but if you prefer the sweet open high-end often attributed to tubes, then you might want to use a good-sounding tube amp on the tweeter (perhaps even a low wattage SET).

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    7 hours ago, Ralf11 said:

    Dick Vandersteen likes bi-wiring...

    I don’t think that changes the physics, do you? It has to take something away. I mean you have replaced a very short strap with a long piece of wire. That adds resistance, capacitance and  inductance. It has to change something, and since wire is passive, not active, it can only attenuate, not amplify. Therefore, some portion of the tweeter’s passband has to be attenuated. So, if Mr. Vandersteen or anyone else hear’s an improvement, it’s because they like a certain portion of the high frequency spectrum being reduced in volume. Am I not right?

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    On 12/25/2019 at 10:37 PM, Sonis said:

    Bi-wiring doesn’t really do anything positive. As far as cable is concerned, it’s like upping the gauge to the wire, but if you are splitting the woofer and tweeter by removing the shorting straps at the speakers and connecting them back together at the amplifier, all you are really doing is moving the place where the woofer and tweeter are joined from the back of the speaker with just a very short, low-resistance strap to a long, higher resistance cable. Sure it can change the sound, but I assure you it is subtracting something rather than adding anything. If you like that better, well, that’s up to you. But you really should know what’s actually going on. 

    I asked if you had ever tried biwiring, you responded with reasons why you believe it isn't worthwhile. I assume that you have not tried, and are therefore working with limited information. I investigated biwiring my system with dual and single 10' runs of Linn K400 13ga cable. Every configuration sounded different; single run to tweeters with short K400 jumper cable to woofer, same except connected to woofers first, and finally biwired. 

     

    I have 12ga zip wire, Linn K400 single and biwire runs and Cardas Neutral Reference bi-wires. There are significant and easily heard differences between them, all in favour of the more expensive options. The opinion often stated by "objectivists" is just to use 12ga from a hardware store does not hold.

     

    You agree that capacitance, inductance and resistance change with biwire vs single run. These base parameters are enough to change the sound, IMO, but there are other potential factors as well, e.g. phase effects: 

    http://www.empiricalaudio.com/computer-audio/audio-faqs/bi-wiring-speaker-cables

     

    and IM effects: https://www.qacoustics.co.uk/blog/2016/06/08/bi-wiring-speakers-exploration-benefits/

     

    Biwiring is in no way essential, but if I have speakers with dual terminals and biwire cables, I will definitely use them. 

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    On 12/25/2019 at 10:37 PM, Sonis said:

    Also, while we’re on the subject, bi-amping a speaker that won’t let you bypass the built-in cross-overs, is also, mostly futile. For proper bi-amp performance you want a small signal crossover BEFORE the amplifiers. Now you’ve got the true advantages afforded by bi-amping! There is an exception to that. Even if you are stuck with the speaker’s built-in crossover, you will still get benefit if, for instance the two amplifiers you are using have vastly different sonic signatures. For instance, if you prefer the bass of a solid-state amp, you might want to put that on the woofer, but if you prefer the sweet open high-end often attributed to tubes, then you might want to use a good-sounding tube amp on the tweeter (perhaps even a low wattage SET).

    I intend to start a new thread on this topic, as I find it fascinating and complex. I will link the new thread here.

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    10 hours ago, audiobomber said:

    I asked if you had ever tried biwiring, you responded with reasons why you believe it isn't worthwhile. I assume that you have not tried, and are therefore working with limited information. I investigated biwiring my system with dual and single 10' runs of Linn K400 13ga cable. Every configuration sounded different; single run to tweeters with short K400 jumper cable to woofer, same except connected to woofers first, and finally biwired. 

     

    I have 12ga zip wire, Linn K400 single and biwire runs and Cardas Neutral Reference bi-wires. There are significant and easily heard differences between them, all in favour of the more expensive options. The opinion often stated by "objectivists" is just to use 12ga from a hardware store does not hold.

     

    You agree that capacitance, inductance and resistance change with biwire vs single run. These base parameters are enough to change the sound, IMO, but there are other potential factors as well, e.g. phase effects: 

    http://www.empiricalaudio.com/computer-audio/audio-faqs/bi-wiring-speaker-cables

     

    and IM effects: https://www.qacoustics.co.uk/blog/2016/06/08/bi-wiring-speakers-exploration-benefits/

     

    Biwiring is in no way essential, but if I have speakers with dual terminals and biwire cables, I will definitely use them. 

    Now, I've tried most everything, including bi-wiring. And yes, it definitely changes the sound of the top end. No doubt. Using an audio spectrum analyzer, I found that in the case of the speaker cable I was using at the time (Symo), the lower treble region was  attenuated about 1.5 dB from around 4KHz to about 6.5KHz compared to single wire. Not a lot, but did it change, on direct comparison, the character of the sound. That's why I say that bi-wiring cannot add anything to the sound, only subtract something from it as it must. Sure, capacitance, inductance and added resistance do, indeed change the sound, but measurement wise, not for the better  (unless it is taming a peak in the speaker's frequency response). But unless you have access many different brands, models, and gauges of wire with which to experiment and some fancy measuring equipment, finding a combination that will improve the sound of one's speakers by attenuating peaks in the FR, for instance,  it's almost impossible to predict the results. Most likely it will makes the speakers sound worse than they did with single wiring. Bi-amping with a low level adjustable crossover before the amplifiers, of course, is a different kettle of fish altogether. 

    Mostly, with cable swaps, and bi-wiring schemes it's a crap shoot, and I have found that many audiophiles, impressed that the sound changes, automatically assume that it's a change for the better, whether it is or not because in their minds, different is always better.

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    I agree that cables are subtractive, but they can also be used to flavour the stew, with subtle but important changes in tonality, detail, soundstage and PRaT. 

     

    It is commonly stated that long interconnects with short speaker cables is preferred over the opposite. At a very minimum, biwiring is equivalent to halving the length your speaker wires. The IM and phase improvements vs. single wire are a bonus.

     

    Judging the value of a cable swap is best determined with extended listening time. Initial impressions can be misleading, it takes time to determine a cable's strengths and weaknesses. Quick changes and A-B testing are useful but not definitive.

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