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MartinLogan Dynamo 600X and Dynamo 1600X Subwoofer Measurements and Analysis

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1600x outdoor testing.jpg

The MartinLogan Dynamo 600X and 1600X were tested using ground plane measurements with the microphone at a 2-meter distance in an open setting with well over 100 feet from the nearest large structure. The subs were tested with woofer and port side facing the microphone for the 600X and woofer side facing the microphone for the 1600X. The subwoofer’s gain was set to maximum, phase was set to 0, and the low pass filter was left off. The weather was recorded at 61°F and 71% humidity.

600x mode responses.jpg   1600x mode responses.jpg

Frequency responses for the modes of the Dynamo 600X and 1600X subwoofers 

The above graphs depict the frequency responses for the Dynamo 600X and 1600X subwoofers for their available modes. We can see that the ‘Music’ mode has a nicely flat response where the ‘Movie’ mode places more of an emphasis on lower frequencies. The ‘Movie’ mode boosts the range from 30 Hz to 70 Hz which can come in handy for those who want to put more weight in effects sounds. Using the Dynamo subs in the ‘Movie’ mode should give them more ‘growl.’ Those who would rather have accuracy would be advised to use the ‘Music’ mode. The ‘Night’ mode filters out a lot of deep bass output. This mode is intended to be the ‘considerate’ mode when listening to content at night but not wanting to bother other people within the same household or apartment complex. This response shape makes sense because deep bass is what travels through walls and obstacles most easily and what will be heard most readily in any nearby rooms. The ‘Night’ mode curve in the 600X graph does not even reach the same amplitude as the other curves because there is a dynamic range limiter that prevents it from getting louder after a certain point. That point wasn’t reached in the 1600X graph but it is apparent in the 600X graph. You can turn up the gain but the subwoofer will not get louder once that limit is reached. This is another good idea for users who want some bass but don’t want to bother other people.

Something else to note about these responses is the high-frequency extension out to 200 Hz. This is good for those who might want to use a higher-than-normal 80 Hz crossover frequency, and there are multiple scenarios where that is useful. It’s especially useful for the 600X, since a small subwoofer like that is more likely to be paired with small satellite speakers, and small satellite speakers don’t normally have any bass extension below 100 Hz. Using an 80 Hz crossover frequency with speakers that roll off above 100 Hz will leave a gap in the bass response, but not every small sub can make the stretch past 80 Hz, especially when they are using heavy cones for a lower resonant frequency.  

600x CEA2010 Data   1600x CEA-2010 table.jpg

Audioholics CEA-2010 Measurement Data for MartinLogan 600X (left) and 1600X (right)

"The 1600X is a mid-bass monster, and these measurements show how hard it can punch..."

The above CEA-2010 measurements are short-term bursts that show the subwoofer’s clean peak SPL before heavy distortion sets in. Our measurements have been referenced to 2-meter RMS, which is 9 dB down from the standard requirement for the measurements to be shown at 1-meter peak. However most publicly available CEA-2010 measurements are shown at 2-meter RMS, so we followed that convention. Standard test frequencies lower than what is shown on these graphs indicates that the subs were not able to produce a passing score at those frequencies, e.g., the 600X was not able to produce passing results at 16 Hz and lower.

The 600X puts up a good showing for a small subwoofer. This is by far the smallest subwoofer this reviewer has ever tested, yet it can manage 100 dB at 31.5 Hz. It hits over 105 dB from 50 Hz to 100 Hz and does so with relatively low distortion levels. It is clear from the distortion levels that MartinLogan has placed limiters in the amp to prevent the subwoofer from beating itself to death or producing gross amounts of distortion. The SPL readings plus the distortion levels comprise a solid measurement set, and this isn’t a surprise to anyone who has heard what this feisty little guy can do. It might not be in the heavy-weight SPL class of subwoofers, but among the welterweights, it is a real bruiser.

The 1600X’s performance is indicative of a different set of performance targets. In low bass, a significant quantity of distortion is permitted, but it does have some output capability in deep bass regions. It’s clear from the very powerful mid-bass but somewhat tetchy deep bass maximum output capability that the driver does not have a tremendously long-throw but does have higher sensitivity and lighter weight. While the distortion quantities look high at 31.5 Hz and below, it should be remembered that this is around the maximum output capability of this sub, and by taking the gain down by just a few dB dramatically reduces distortion. The driver here is being pushed way past its linear operational range which is easy to do with a sealed subwoofer in deep bass. We will get a better look at its distortion behavior at nominal levels in our distortion graphs of long-term tones.

At 40 Hz and above the 1600X is an output monster. Its 50 Hz and 63 Hz CEA-2010 burst measurements sets a new record for output among subs that I have reviewed. Distortion in the range is quite low too. The 1600X is a mid-bass monster, and these measurements show how hard it can punch in this frequency band. 118 dB in this frequency range is a savage thing to experience; I can’t recommend it enough. Those who like bass-heavy music at high output levels would enjoy the dynamic range offered here. 

 600x compression sweeps.jpg  1600x compression sweeps.jpg

Dynamo 600X (left) and 1600X (right) long-term output compression 

Testing for long-term output compression was done by first conducting a 20-second sweep tone where 50 Hz hit 90 dB with the subwoofer 2 meters from the microphone. We then conduct further 20-second sweeps by raising the gain by 5 dB until no more output could be wrung out of the subwoofer. These tests show us the long-term continuous headroom that these subwoofers are capable of. In these measurements, we can see the 600X puts out a respectable performance showing, exceeding 100 dB at 35 Hz and above and even touching 105 dB from 50 Hz to 80 Hz. That is a very good showing from a petite, modestly-priced cube subwoofer. The 1600X is a different matter entirely. Its output advantage hovers around a 9 dB to 11 dB difference. This roughly equates to three to nearly four times the output of the 600X. This is about proportionate to the price difference. The 1600X exceeds 110 dB from 35 Hz to 200 Hz and even hits 115 dB from 50 Hz to 90 Hz. Those kinds of output levels give it a very tactile sensation when driven to those extremes. One extra advantage that the 1600X holds over the 600X is that its sealed design allows it to have deep bass output below 20 Hz. In smaller rooms, pressure vessel gain can give a disproportionate boost to low frequencies where there is some output in that region, and the 1600X is better positioned to produce that kind of deep frequency room gain.

600x THD.jpg

1600x THD.jpg

MartinLogan Dynamo 600X and 1600X Total Harmonic Distortion per output level (note: the 1600X graph dips down to 10 Hz whereas the 600X graph stops at 20 Hz.

Before jumping to conclusions about the distortion quantities shown here, read below paragraphs to learn why the 1600X’s graph is extended and the significance of these distortion shown here) 

The above graphs show the corresponding total harmonic distortion to the long-term output graphs. Essentially, they depict how linear the subwoofer remains for the corresponding drive level seen in the long-term sweeps. The quantity being measured is how much of the subwoofer’s output is distortion and is shown here as a percentage.

One aspect about the above graphs that need to be stressed is they are aren’t comparable to each other: the X-axis needs to be closely looked at. In the graph for the 600X, I have cut off the X-axis at 20 Hz, so it is only showing the frequency range from 20 Hz and above. I have allowed the graph for the 1600X to go down to 10 Hz. So at a glance, it looks like the 1600X has a lot more distortion, but the truth is very different. I cut off the X-axis at 20 Hz in the 600X graph, because the 600X had so little deep bass output that the noise floor actually constituted a substantial portion of what was recorded as distortion, and so it looked like the 600X had a lot more distortion at low drive levels than at higher drive levels. Of course, the opposite is true, because distortion is being shown here as a percentage, and the noise floor is going to constitute a greater percentage of the overall recorded sound at low output levels versus higher output levels. The 1600X doesn’t have this problem because it is generating significantly more energy at every drive level and every frequency, so its own output greatly outweighs the noise floor below 20 Hz.

Nonetheless, the 600X is a very clean performing sub. At its highest drive levels, it can’t really be pushed too much beyond 10% THD above 20 Hz. Distortion below 20 Hz does not matter for it so much since output rapidly drops off. Sometimes subwoofer manufacturers will allow a great deal of distortion from their smaller subwoofers; they try to wring as much output as possible from them since smaller subwoofers will be inherently output-limited. MartinLogan clearly does not subscribe to that design goal. Linear behavior was very much in their minds in the design of the 600X. The 90 and 95 dB sweeps don’t even pierce 5% THD until under 25 Hz. Those who need a smaller-sized subwoofer but do not want to give up accuracy or linearity would do well to give the Dynamo 600X a close look.

"That is some of the cleanest bass I have ever measured..."

Regarding the 1600X, while it looks like it distorts more than the 600X from just glancing at these graphs, the viewer must keep in mind the output levels at which this distortion is occurring. In reality, the 1600X produces considerably cleaner bass than the 600X for most of the subwoofer frequency band. What the higher quantities of distortion in the 1600X graph are telling us is that the 1600X can be pushed to more distortion than the 600X from around 40 Hz to 20 Hz. Below 20 Hz, the 600X is not producing any meaningful bass sound, and what little sound it is producing is almost entirely distortion, as it is with most other ported subwoofers below their port tuning frequency. When the 1600X is pushed hard in deep frequencies, it will run into distortion, however, decibel-for-decibel, the 1600X is mostly generating cleaner bass than the 600X. At 90 dB test tone, it hovers around 1% THD from 40 Hz and above, and at the 95 dB test tone, it barely pokes its head above 2% for that same range. That is some of the cleanest bass I have ever measured, and it is far below any audible threshold. 

It should also be mentioned here that while I absolutely throttled both subs and pushed them to their limits during testing, I was not able to make them bottom out, so they appear to be well-protected from being driven into self-destruction. That can give the user a nice sense of security for the moments where they want to show off the subwoofers in demos to friends or just want to see how far these things can go. Of course, it is not advisable to run them really hard all the time, since that would considerably shorten their lifespan, but it’s nice to know that driving the subs hard once in a while will not kill them.

600x distortion components.jpg

1600x distortion components.jpg

Component Harmonics of the Dynamo 600X and 1600X  (note: the 1600X graph dips down to 10 Hz whereas the 600X graph stops at 20 Hz. This makes the 600X appear to have less distortion relative to the 1600X than it actually does if the X-axis range is not considered) 

The above graphs depict measurements of the constituent harmonics from the long-term output sweeps and are what the total harmonic distortion measurements are composed of for the 2nd and 3rd harmonics. These individual harmonics can give us a clue as to what might be the cause of some quirk or non-linearity. We are only showing the 2nd and 3rd here because they more or less reflect the higher even-order and odd-order behaviors, although higher-order harmonics will likely not be as abundant in quantity as the 2nd and 3rd harmonics.

Examining the 600X’s results, we see that there is far more even-order distortion than odd-order, and this indicates some non-linearity that is only affecting one direction of the cone’s travel. Port artifacts can do this, as well as tension in the suspension that inhibits one direction of excursion more than the other, but given the shape of the curves, the steady rise in the distortion, and the relatively even amount over the entire frequency band, this even-order distortion looks to be the product of induction effects. Induction in loudspeaker drivers is when the changing magnetic field from the movement of the voice coil next to the stationary permanent magnet causes a counter-current that can interfere with the initial current thereby inhibiting linear motion that is faithful to the source signal. The good news here is that even-order distortions are more difficult to audibly detect than odd-order distortions, and there isn’t enough distortion here to worry about. This is a surprisingly clean subwoofer given its size. As was mentioned before, many small subs can be pushed hard in order to squeeze out as much loudness as possible, but MartinLogan has wisely not taken that tack.

The 1600X looks to also have some induction effects present in the even-order harmonic distortion, but, as with the 600X, they are in very modest quantities outside of high drive levels in deep bass. We can see that 3rd-order harmonic distortion really takes off above the 110 dB tone sweep below 30 Hz. This is likely the driver’s voice coil blowing past the top-plate gap where the magnetic field is very tightly controlled. Once outside of this region of control, the moving mass of the driver isn’t able to react as tightly to changing swings in the signal voltage and runs into heavy distortion. The 1600X driver is not an extremely long-throw driver, and this has advantages as well as disadvantages. A disadvantage is that it doesn’t really produce deep bass really well on its own. It can produce deep bass cleanly, but only up to a limited point. An advantage of this design is that long-throw drivers tend to be heavy which limits their mid-bass output. The 1600X banks on its lightweight design to produce prodigious amounts of mid-bass. Most distortion in the mid-bass region is even-order as well, so what little distortion is generated in that region is of a relatively harmless type, not that those quantities would be audible in that range to begin with.

600x group delay.jpg 

1600x group delay.jpg

MartinLogan Dynamo 600X and 1600X group delay 

the bass decays very quickly....any boominess heard is room related not attributable to the Dynamo subs.

Group delay is the measurement of how much time it takes for individual frequency bands of an input signal to be produced by the speaker. It can indicate that some frequency components are developing slower than others or are taking longer to decay. It is generally thought that 1.5 sound cycles are needed for group delay to be audible at bass frequencies, although there is an argument that group delay should remain under 20 ms to be completely unnoticeable, but that is likely meant for mid and upper bass frequencies. Both the 600X and 1600X boast very good metrics here. The 600X stays well below 1 cycle or 20 ms until very deep bass where it is beyond audibility. The 1600X never pierces 1 cycle and doesn’t go over 20 ms until 30 Hz. There is a rise in group delay below 30 Hz in the 1600X measurement that is evidence of a high-pass filter, but it is well beneath any audible threshold. The bass in both subwoofers decays very quickly. Evidently, MartinLogan was very concerned with time-domain issues and sought to engineer a subwoofer that would be free of any stored energy, and on this count, they have done a stellar job. Any boominess or sluggish bass sound from a system with these subwoofers would be attributable entirely to acoustic conditions that the subs are being used in, and not the Dynamo subs themselves.

600x 20-30Hz Level diffs.jpg   1600x 20-30Hz level diffs.jpg

Examples of the effect of the 20-30 Hz Level Adjust Control 

One of the controls on the Dynamo’s subwoofer control app is an adjustment to the 20-30 Hz region. This control raises or lowers the response in the 20-30 Hz frequency band. For the curious, I have included some measurements that demonstrate its behavior. It is essentially a parametric level adjust with a fixed frequency and it does raise and lower the low-end response, but its Q is wide enough to have a considerable impact outside of the 20-30 Hz region. It is useful for either boosting or reducing low-frequency output to the user’s taste.

Conclusion

1600x close up.jpgThe original Dynamo subwoofers were an enormous success for MartinLogan, and I can now understand why. MartinLogan takes a practical, accessible approach to subwoofer design. Many of my past reviews were of subwoofers that were very large, and they needed to be in order to chase the very deep frequency output that was their performance targets. The reality is that these large sizes make them impractical for a large percentage of audio shoppers. Most people do not want their living space to revolve around audio gear; they want good sound, but they do not want to give up the floor space to something that is as big as a piece of furniture that only produces bass sound. Such people are called normal people, and sometimes we audio enthusiasts forget that more can be done in a living space than merely setting it up to listen to an aural recreation of an event somewhere else.

The Dynamo subwoofers may not be thBassaholics_Large.jpge deepest digging subs out there, but they do capture much of the recorded bass content of movies and music. They do so cleanly as well; the 600X generally doesn’t produce much distortion in its operational range, and the 1600X doesn’t produce much distortion above 40 Hz, although it is capable of producing some distortion below 40 Hz when pushed hard. However, every sealed subwoofer will behave similarly unless it has very strict filters which dramatically limits deep bass output. And while the 1600X can be pushed into distorting in deep frequencies, it is protected from overdriving itself into any harm. When size is taken into consideration, both the 600X and 1600X tout some very good performance numbers. As was mentioned before, the 1600X is an output monster at 40 Hz and above, and it nets a ‘Large’ room rating in Audioholic’s Bassaholic room rating, meaning it should be able to handle room sizes from 3,000 to 5,000 cubic feet. The 600X merits a ‘Medium’ room size rating, so it should be able to handle 1,500 to 3,000 cubic foot room sizes. It’s worth mentioning here that the 1600X majorly outperforms its predecessor, the 1500X, when their measurements are compared (Dynamo 1500X review measurements).

"This generation of Dynamo subwoofers is clearly a major leap over the previous generation in every respect."

But performance is only one part of the story of MartinLogan’s new Dynamo subwoofers. Their plethora of wireless features is also a big selling point of these subwoofers. MartinLogan’s subwoofer apps make fine-tuning the sub easy. The user does not have to fiddle around with a bunch of cryptic knobs on the back panel to make adjustments to the subwoofer; it is all done from a smartphone app that has accessible explanations for each of the myriad of controls. The ARC Mobile App was also easy to run and very clear in its instructions. It didn’t really do much more for me than trim a minor peak at 40 Hz, but at least it was smart enough not to attempt to fill in any nulls. And while I didn’t use the SWT-X Wireless Subwoofer System, I like knowing that I can get wireless signal transmission without needing an additional power output plug. The Dynamo subs aren’t really plug’n’play devices any more than any other subwoofer, but what is nice about them is that once you plug them in, most of the setup is done from your sofa, where you can hear the results of setting changes in real time at your listening position, instead of hunched over the sub while trying to dial it in.

600x corner view.jpg

The Dynamo subwoofer’s clean appearance also has a lot to do with its practicality. These are subs that do not draw attention to themselves and therefore can fit in nearly any decor. The satin black finish is tasteful and the cabinet is simple, so while these subs would be a perfect fit in modern interior decor, they aren’t likely to clash with traditional home styling either. Another aspect of their practicality is their reasonable weight. At 35 lbs. for the 600X and 57 lbs. for the 1600X, these are subwoofers that almost any healthy adult can lift up and carry without much problem. As a subwoofer reviewer, it’s been a while since I have had such easily movable subwoofers, so I can especially appreciate that!

1600x ML logo.jpgI am guessing that MartinLogan is going to continue their winning streak with these new Dynamo subwoofers. They sound great, they can be integrated into any system and any room, they are a breeze to set up and dial-in, and they are not exorbitantly expensive. I think those who want a subwoofer in their living room but have to compromise on the size of the sub for other household occupants are going to be pleasantly surprised by the performance of the 600X. I also think those who end up with a 1600X will be shocked at the sheer amount of punch it has for such a modest-looking piece of audio gear. This generation of Dynamo subwoofers is clearly a major leap over the previous generation in every respect; I know it will be years until the next generation, but I am already eagerly looking forward to where MartinLogan goes from here based on the terrific work that they have done on these subwoofers.

The scores below reflect both the Dynamo 600X and the Dynamo1600X, although the 600X scored slightly lower in the bass response and performance category.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStarStar
Build QualityStarStarStarStar
Ergonomics & UsabilityStarStarStarStarStar
FeaturesStarStarStarStarStar
Dynamic RangeStarStarStarStarStar
Fit and FinishStarStarStarStar
PerformanceStarStarStarStarhalf-star
ValueStarStarStarStarhalf-star
Attached Files
About the author:

James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.

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