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Martin Logan Dynamo 1500X​
By Jim Wilson (theJman)

The subject of this review is the Martin Logan Dynamo 1500X, an acoustic suspension subwoofer that utilizes a 15" driver. It's probably the smallest 15" unit you're likely to ever encounter, measuring just 18.3 x 16.75 x 17.6 (HWD, in the down firing orientation) and weighing a mere 51 pounds. The dimensions and weight are closer to what you might expect from a subwoofer utilizing a 12" driver. The Class D amp is rated for 650 watts RMS and 1300 watts peak. The frequency response is listed as 20-200Hz (+/-3dB).

Martin Logan (ML) is a well known name, long established in the audio world. Most people are probably familiar with their phenomenal Electrostatic panel-style speakers, which are renowned for their wonderful life-like sound. However, ML offers far more; they have a multitude of options for both home theater and 2 channel music systems.

The Dynamo 1500X lists for $1595 in the Satin Black finish and $1895 for the Gloss Black that the review sample came in. ML sells primarily through dealers, both small and large.

The warranty they provide works a bit differently than most others. You get 90 days instantly, but then you can 'extend' that to 3 years if you register the subwoofer within 30 days. You'll need to provide proof of purchase though, so be prepared for that. Martin Logan explains this unusual process thusly:

As a manufacturer of products operating at the outer limits of contemporary audio technology, we feel it is extremely important to have the most comprehensive information possible relating to actual field use so that areas of potential improvement may be rapidly recognized. For this reason we ask that you fully complete your registration card before returning it

An (unintended?) consequence is perhaps to deter 'grey market' sales of their products. I don't know this for a fact, but since ML still employs a dealer sales model it's not unreasonable to assume.

The review unit was only single boxed, but looking at the cross section of the top flap revealed it's approximately 1.5 times the thickness of a standard box. Not ideal, but it should prove sufficient. The Dynamo 1500X was held in place with custom molded hard styrofoam that covered the entire top and bottom of the box. The grill was contained in its own slot, where it sat encased in bubble wrap. The Dynamo 1500X itself was inside a cloth bag, which in turn was inside a plastic bag.

The included accessories consisted of 4 small 'Energy Transfer Couplers' (metal carpet spikes to you and me), a 2 prong power cord with a 90 degree bend and a pair of RCA adapter plugs, also with a 90 degree bend. These unique accessories are to facilitate the variable orientation feature of the Dynamo 1500X. More on that a bit later.

The diminutive appearance -- relative to the driver's size -- is the first thing people notice, but it's not the most unique part of the Dynamo 1500X. That honor goes to the variable orientation, which allows you to tailor the subwoofer in a manner that very few other manufacturers offer. Do you prefer a down-firing subwoofer? That's really easy because it comes out of the box configured that way, so there's nothing to do but hook it up. Would you rather have a front-firing subwoofer instead? No problem, just unscrew the feet, re-attach them on the other side and pop on the grill. Voila, it's now front-firing. To change the configuration takes all of 5 minutes, but the front-firing orientation does come with a few potential drawbacks.

If you opt to change from the default down-firing configuration the amp ends up on what then becomes the underside of the cabinet, meaning the controls are no longer within easy reach. ML thoughtfully includes a power cord and RCA adapters that accommodate front-firing quite well for unbalanced connections (RCA style), but you can forget about using the balanced (XLR) connector because there's no 90 degree adapter for that.

Once you switch to front-firing you also need a grill which, as you might expect, is included. However, it's not a very impressive piece. It's built using a lattice style design, but the plastic is pretty thin making it rather pliable. The cloth material used is very transparent, so it won't block any of the sound thankfully. The L-shaped feet aren't all that remarkable either; they don't strike me as particularly sturdy, but since the sub isn't heavy I don't envision any problems. Considering the price of the Dynamo 1500X I'm a bit surprised the grill and feet aren't more substantial.

ML certainly didn't skimp on the documentation, because that's excellent. The Owners Manual is rich with details about everything you could possibly imagine; sub placement, options and their usage, general hook up and even suggested settings. It provides solid information and clear pictures about every aspect, making it so even a person unaccustomed with subwoofer configuration should be able to setup the Dynamo 1500X in no time.

The screws holding the driver needed maybe 1/4 turn to snug them down, while on the amp they were already tight. One thing I found rather uncommon -- in a good way -- was a QC tag attached to one of the amp dials that had been filled out by hand. I'm not sure if that indicates the unit was built in the US, or perhaps just tested here, but I thought that was a nice touch. Another thing I liked about the Dynamo 1500X was the fact it went in and out of standby mode flawlessly, and never once tripped over itself. I always consider that a plus.

The 15" driver is impressive looking. It's manufactured by Martin Logan's sister company Paradigm (they're both owned by ShoreView). It utilizes a polypropylene cone with an over-sized rubber surround. The voice coil is a high-excursion, extended throw type nestled in an 8 spoke cast aluminum basket. The cabinet is so small, relative to the driver size, that the trim ring is actually shaved down on three sides in order for it to fit properly. ML must not want it to go any place either; instead of using the customary 8 screws to anchor it down they opted for 12. They're only wood screws though, which for a sub in this price class is a bit unusual.

When I removed the driver to take photos I noticed something very interesting; a 2nd set of leads. That additional connection is attached to a thermistor which the protection mechanism uses to sense the internal temperature. Rounding out the driver are dual stacked magnets and a tiny rear vent. There's more venting around the base of the frame, providing what appears to be ample voice coil cooling. Oddly, there's no bump-out for the voice coil itself.

After I got over how small the cabinet is the next thing that struck me was how light it was. That's not necessarily a good thing for a subwoofer, where rigid enclosures and massive magnet assemblies on drivers are the norm and tend to add weight. It's constructed from .75" MDF and does include cross bracing. Lining the interior walls are 2" deep sheets of dense cotton damping. The proverbial 'knuckle rap test' returned a fairly inert sound, with little ringing. The review unit came with the optional high gloss black paint, which was applied very nicely. There's a discrete ML badge on the bottom of the front panel, but it proved a bit too innocuous for my tastes because it virtually disappeared into the paint. In spite of that minor stumble the Dynamo 1500X looks elegant.

The amp is a lesson in simplicity, with few controls or inputs. The three knobs are conical in shape and have a brushed silver look. There's one each for the Level, Phase (variable from 0-180 degrees) and Low Pass Filter. The latter can be adjusted from 30-150Hz, but if you rotate it all the way to the right it will be in Bypass mode. Audio inputs consist of a single Balanced XLR and a pair of unbalanced RCA's, with the Right input doing double-duty as the LFE In. The lone switch is a toggle that controls power and has but two settings; Auto and Trigger (no independent On or Off). Right next to that is the Trigger input, which can accept voltages ranging from a low of 5VDC all the way up to 24VDC. Typically the only input voltage is 12VDC, so the Dynamo 1500X should be able to accept a trigger from a wide variety of equipment. The final input is for the Perfect Bass Kit (PBK for short). All the internal electronics are housed in sturdy metal enclosures, which should help shield them from the pounding back-wave of the driver.

The aforementioned PBK is Martin Logan's room correction system, which is essentially Paradigm's Perfect Bass Kit. As the name implies it's designed to adjust lower frequencies, so it only works on subwoofers. As every one of us knows all too well each room presents unique challenges when it comes to properly tuning your HT system. Certain versions of room correction software -- like Audyssey XT32 -- are able to make changes to a subwoofer's response, but those systems are designed without explicit knowledge of your particular subwoofer. Enter the Perfect Bass Kit, which knows everything about the Dynamo 1500X and how to tune it.

The PBK consists of a specially calibrated USB microphone, a CD with the Windows PBK software, two USB cables, an adjustable tripod and the Operators Guide. That's a lot for only $100. After installing the software on your computer you connect it to the microphone using one of the supplied USB cables. You then take the other USB cable and run that from your computer to the special port on the back of the Dynamo 1500X. Before running the calibration sequence you set the subwoofer's gain to 50%, rotate the LPF dial to Bypass and set the phase to 0. Now you're all set to start the equalization process.

The first thing you need to do is make sure the microphone is at ear height in the primary listening position. The included tripod is there to help with that part, but the distance from the Dynamo 1500X to where you sit could prove to be a challenge. The USB cables were about 8' each, meaning if your laptop was in the middle you could measure from a distance of only about 15 feet. Since my primary listening position is just 11-12 feet from the subwoofer it wasn't an issue for me, but longer distances wouldn't be as painless.

The Operators Guide very specifically states the microphone must be pointed towards the ceiling when taking measurements. One thing I was surprised by was the fact you have to measure from a minimum of 5 distinct locations, each of which must be at least 2 feet apart. That strikes me as a bit excessive, especially when most other room correction systems can get by with just 3 samples. Either way, the process is quick and simple to perform so it only takes a few minutes. Like all other component-specific equalization systems you must run the PBK before calibrating with your AV receiver's software (Audyssey, YPAO, MCACC and the like). The reasoning is that you want to ensure the Dynamo 1500X is tuned and working optimally prior to EQing the rest of your system.

So how did it work? I didn't get "perfect" bass, but it did do quite well taming a nasty room mode I have centered around 40Hz. Usually that one runs about 7-8dB high. The PBK trimmed it around 6dB, making a noticeable improvement in sound quality. I also have about a 5dB peak in the mid 80Hz range, but that was only trimmed perhaps 2dB. The dip you see around 60Hz is a room null unfortunately, so there's not much any EQ system can do about that I'm afraid. For those keeping score the PBK did an impressive job with one huge peak and OK with a smaller one. I did run the equalization process more than once to see if that would make any difference but it didn't appear to, at least not in any material way.

This measurement was taken at the primary listening position. Green is before the PBK was run, while cyan is after.

My living room is 13x17x8 (1768 CF), so it's not terribly large. The main seating position is approximately 11 feet from the subwoofer. All testing was done after the unit had been broken in for close to 50 hours. Yes, 50 hours; the 1500X Owners Manual actually recommends that, which is pretty close to how long I let it run before doing any critical listening.

If I had to pick a single word to describe the Dynamo 1500X it would probably be 'omnipresent'. This subwoofer lets you know it's there pretty much all of the time, and I don't mean that in a bad way either. The bass is pervasive, yet it never really struck me as over-exaggerated or terribly embellished. Even when doing something as innocuous as watching an NBA playoff game -- which I'm wont to do frequently this time of year -- the sound just seemed right. What type of bass is there in an NBA game? The bouncing of the ball and the stomping feet from the crowd are good examples. As the players were driving it up and down the court the Dynamo 1500X was adding a solid presence, making it almost seem like you were actually at the game (sit close to the court at a real game sometime and you'll know what I mean). This subwoofer is no wallflower, that's for sure.

My proclivities have always been towards small acoustic suspension subwoofers. As such, the Dynamo 1500X is almost everything I look for in a sub; sealed design, not very large, solid dynamics, impressive composure and chair-rattling bass. That last quality is not a misprint either. Its small size should have precluded it from producing much in the way of a tactile sensation, yet frequently while watching blu-ray discs waves of bass were sent cascading through my chair. I felt the precision and detail could have been a little better on occasion -- I detected a hint of compression once in a while -- but depth was never an issue.

Considering the volume I was reaching at times during the review, which was -5dB quite often, output was never really a problem either. The pronounced cone movements caused a touch of distortion every once in a while, and the clarity suffered slightly because of it, but that's pretty much to be expected when any driver cone is moving to the degree this one was. Even when asked to produce significant output levels the Dynamo 1500X remained poised almost all the time though. With very few exceptions I liked what I was hearing, no easy feat given how hard I pushed it. When used at a normal output level there was never an issue, and the Dynamo 1500X simply oozed bass.

I run each test scene twice; once while seated in my normal listening position, and then a second time while sitting a few feet from the subwoofer. This allows me to hear it as I normally would, yet also affords me the opportunity to determine if the subwoofer is straining even the slightest bit. Both tests are run at the same volume level, which is slightly above what I would normally use on a day-to-day basis.

Cloverfield (blu-ray)
When the Empire State building collapses during Scene 5 there were waves of deep bass coursing through my chair. That effect was palpable, and one of the better renditions I've heard/felt in a while. The Dynamo 1500X lent considerable heft and weight to the bedlam that ensued during the destruction of the Brooklyn Bridge too, when one of the sea creatures uses its massive tentacle to bisect the bridge. The best part was Scene 8 though, when the ground troops attack the creature for the first time. There is a tremendous amount of bass encoded into the LFE soundtrack, and this little subwoofer played right along. The beast's footsteps had a fabulous rumble, artillery strikes were potent and realistic. None of the chaos seemed to faze the Dynamo 1500X.

Avatar (blu-ray)
As the Assault on Home Tree unfolds we find the enemy soldiers approaching in gunships. The roar of there engines was potent and clean, resembling what it might sound like were you actually their. As they unleash their fury on the roots of Home Tree each component of the attack had excellent impact; from the dull thud of the incendiary rounds, to the depth from the missile reports, every element was distinct and produced the correct amount of power to make it believable. When Home Tree inevitably succumbs to the relentless onslaught the enormous roots buckle, the tree begins to list, huge branches start to crack and then finally it comes crashing to the ground. The Dynamo 1500X went along for the entire ride, without a single misstep.

LOTR: Return Of The King (blu-ray)
Because it proceeds in stages the battle for Gondor encompasses a couple of scenes in this movie. During a few of them -- like The Ride Of The Rohirim and The Pyre Of Denethor -- there are several instances where the sounds of battle create a multitude of explosions and impacts, all of which were produced exceptionally. However, the real action starts when you get to the Battle Of Pelennor Fields. That's when the Orcs and Uruk Hai team up with the renegade warriors on their Olephants. The Olephants are colossal beasts that bear a striking resemblance to elephants (surprising given their name, isn't it?). At perhaps 10 stories tall they create an imposing figure, and as you would imagine every time one of their massive feet hit the ground the effect should confer that. And it did, with thunderous impact and the requisite ripple of bass. The Dynamo 1500X gave you a ring-side seat to the action.

Tron (blu-ray)
I figured it might be worth giving Tron a spin, just to see how this little sub would handle the over-driven LFE track. As it turned out, the Dynamo 1500X was up to the task.

The engines on the Transporters that pick up Sam Flynn were potent, with very good definition. I've found this part to be one of the more difficult effects for a subwoofer to reproduce accurately, feeling it often came across as blurred and lacking distinction. Not this time. The pulses from the elevator that take Sam down below the stadium were clear and solid as well.

The Lightcycle Battle scene was a real treat. It started off on the right foot with a brilliant rendition of the fireworks that precede the competition. I gambled a bit by turning up the volume another 5dB because it was sounding so good, which is where I left it for the next 10 minutes or so. The little Dynamo shrugged it off though, and continued to sound quite good regardless of how much was going on. Whether it was the rumbling from the lightcycle engines, or explosions from the cycles as they hit the invisible barrier that rings the Grid, it all came through with remarkable authority.

After all the testing had concluded I checked the amp to see how hot it had gotten. It was fairly warm, but not excessively so and cooled down pretty quickly.

For me the "acid test" is always music. As far back as I can recall -- and no, I'm not going to divulge how many years that really is -- music has been a huge part of my life, so I'm very critical in that regard. After crushing the movie tests I was curious to see how the Dynamo 1500X would do when I started evaluating music. Turns out it's equally adapt.

Don't Treat Me Bad - Firehouse (MP3)
This song is from their debut album, and is probably the biggest hit they had. Most of the music Firehouse made struck me as somewhat cliche, so they certainly weren't my favorite band from the era. Don't Treat Me Bad has an inordinate emphasis on the kick drum though which makes it ideal for a subwoofer test, and boy did the Dynamo 1500X deliver on this one. Every time Michael Foster pushed that pedal down the sound flooded my room with a resounding thud, very similar to what might occur at a live show. Even with the altiloquent drums you could still hear Perry Richardson's bass guitar, so in spite of the sound engineers attempt to drown out almost the entire rhythm section with the bass drum the Dynamo was able to maintain its composure.

All I Know - Screaming Trees (Streaming)
All I Know was from their Dust album, which was their last one. You never knew what to expect from Screaming Trees - each release was a different style of music than their previous ones, so it was hard to keep up with them. Most of their songs I don't particularly enjoy, but for some reason All I Know gets stuck in my head whenever I hear it. Just like Don't Treat Me Bad this one has a prominent kick drum, but it differs from the Firehouse song by also having a pervasive bass lick. The Dynamo 1500X had no trouble here either; the drum had a potent thump, while the bass guitar was rich and powerful. I cranked the volume when I listened to this tune the second time, yet it was just as clean.

Teutonic Terror - Accept (CD)
The very first version of what would ultimately become Accept can be traced back over 40 years ago when Michael Wagener and a pint sized vocalist named Udo Dirkschneider teamed up to form a band. Since then at least a dozen members have come and gone -- including both Michael and Udo -- so its never resembled any particular incarnation for very long. Udo was perhaps their most famous member because of his physical stature, or lack thereof; I don't think he would be 5 feet tall standing on his toes. Think along the lines of Klaus Meine (Scorpions), Bon Scott (AC/DC) and Ronny James Dio. They were all vertically challenged guys with out-sized and powerful voices.

Teutonic Terror is from their Blood Of The Nations album, which was only released a few years ago. This style of song is one of my favorite genres; aggressive high energy music with a pounding rhythm and quick changes. I can set Teutonic Terror on repeat and listen half a dozen times without getting tired of hearing it. So guess what I did? Yup, I turned on repeat and played it a few times (not 6 though). The Dynamo 1500X loved this song, and so did I. Peter Baltes's Rickenbacker sounded just like a 'Ric' should sound, with the appropriate heft and power which that wonderful bass guitar is supposed to have. Stefan Schwarzmann's double-time drum rhythm was lightning quick and never seemed to lose distinction because of the speed. Everything blended smoothly and produced a rollicking rendition of this song.

Sister Havana - Urge Overkill (CD)
From the Saturation album I chose Sister Havana. This is one of those toe-tapping kind of songs, with an infectious rhythm. Urge wasn't really into mainstream music until this album, when it seemed as though they changed course and were deliberately trying to get some radio airplay. It worked, and Sister Havana made the Top 10. It seems one of the prerequisites for a song such as this is the bass and drums be recorded on the hot side, and Sister Havana is no exception. On this track the Dynamo 1500X did an incredible job of duplicating that energy. The quick changes and tight rhythm came across with authority and power.

Virtually everyone has heard the phrase "you can't have your cake and eat it too". In essence that means whatever you're referring to has a choice associated to it and you won't end up with both options working in your favor, regardless of how desirable they each may be. With a subwoofer that saying generally holds true when talking about size versus depth/extension; a small subwoofer can't possibly produce significant amounts of deep bass, can it? In the case of Martin Logan's new Dynamo 1500X the answer would be Yes, you can have your cake and eat it too. The cabinet is not at all large -- even for an acoustic suspension subwoofer with a 12" driver, let alone one with a 15" driver -- yet the depth and composure it's capable of is simply amazing. At times I wished for a touch more detail, but to be honest I could live with this subwoofer every day and be quite satisfied. It's not inexpensive, but it is certainly capable of some impressive bass. The 'Dynamo' name proved to be apt, that's for sure. With the flattest frequency response I've measured in a long time, this Martin Logan subwoofer is one very impressive unit.

Please use the Martin Logan Dynamo 1500X Discussion Thread for questions and comments​

Dynamo 1500X Pictures

Dynamo 1500X Measurements

These measurements were taken using XTZ Room Analyzer II Pro. The unit was indoors, physically positioned in the center of my listening room with no other speakers running.

This represents the performance when configured as a front-firing subwoofer

This represents the Spectrograph of the driver
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