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MartinLogan Dynamo 1500X Measurements

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The MartinLogan Dynamo 1500X was placed outdoors in a large field with the nearest large objects a minimum of 60ft or greater away from it, with the driver facing towards the microphone. The balanced XLR input was used and an ACO Pacific 7012 measurement microphone was placed on the ground at a distance of 2 meters from the nearest enclosure face of the 1500X and pointing towards the driver. The amplifier was set to maximum gain, the phase was set to zero, the low pass filter was set to bypass and no PBK equalization was in effect. All measurements were taken in this configuration unless otherwise specifically noted. For more info on the testing equipment and procedures please see the article here. 

Powered Subwoofer Testing Outline and Procedures Overview

 

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MartinLogan Dynamo 1500X: Effect of Low Pass Filter on Response

Above are the frequency response measurements of the 1500X showing how adjustment of the low pass filter affects the top end response. The roll off slope is 24dB/octave and the -3dB point agreed well with the indicated setting on the dial.

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MartinLogan Dynamo 1500X: Basic Frequency Response as Tested

With the low pass filter disabled the 1500X produced its flattest response but the general shape was of a rising response into the deep bass down to 24Hz, a response that is filtered off above 150Hz and the rapid drop off below 20Hz of about 36dB/octave indicates that a 4th order high pass filter is in effect below 20Hz. Overall the resulting response shape fits within a 6dB total window from 19.5-162Hz which is very close to MartinLogan’s stated response of 20-200Hz +/-3dB but with a bit less upper end extension. The 1500X’s response shape is more like what you would expect to see from a large vented subwoofer with a 20Hz tuning than a small sealed subwoofer. There is a significant amount of processing going on to force the 1500X into this response shape. I must admit that I am not a big fan of equalizing small sealed subs like this.

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MartinLogan Dynamo 1500X: Group Delay

Group delay measurements for the 1500X indicate that there is some energy delay centered at about 20Hz corresponding with the boost equalization and high pass filtering used. The group delay is well mannered down to 30Hz where it starts to increase until it just barely exceeds 1 cycle of delay from 19-25Hz. Still at such deep frequencies and with the group delay just barely breaking 1 cycle it is doubtful that this is of any audible consequence.

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MartinLogan Dynamo 1500X: Long Term Power Compression

The long term output compression tests for the 1500X show that it responds in a linear manner to increased output demands up through the 100dB sweep at which point it has reached its maximum output potential near 20Hz reaching an output of about 97dB. As the 1500X is asked for more output it responds by producing what it can without any overtly bad noises. The 1500X was still producing increased output as demanded during the 115dB sweep. Finally during the 120dB the 1500X was completely out of headroom over the full bandwidth but it is notable that despite it being driven so heavily into compression in the deep bass it never sounded like it was in any real danger and behaved in a very stable and repeatable manner. By that point the 1500X was producing over 110dB above 40Hz.

Note on Output Compression Testing: This is by far the most demanding measurement type conducted on the subwoofers during our testing and will reveal any issues with overload, port compression, port noise, driver distress, creaks, rattles, buzzes, etc. Additionally the test is conducted outdoors with just the subwoofer operating so there will be no nearby walls or objects to vibrate and no upper frequency content from other speakers in operation. These would normally help to cover up or mask any objectionable noises from the subwoofer in a typical room. Any sort of audible distress or issues with the subwoofer are readily apparent in this environment.

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MartinLogan Dynamo 1500X: Output Compression Magnitude

Looking at only the amount of compression occurring in the output of the 1500X It can be seen that it does excellently through the 100dB sweep with virtually no compression. Compression starts to set in centered at 22Hz in the deep bass during the 105dB sweep this is due to the large amount of boost equalization applied to the 1500X to extend the response. However this also means that the 1500X uses up all of its headroom near 18-25Hz very early. Since that is the case the 1500X simply stops getting any louder between 16-30Hz. Thankfully the engineers at MartinLogan correctly matched the amplifier potential to the driver and dialed in their protection circuits very well, so while the 1500X will compress early in the deep bass it will not get damaged or allow the driver to produce gross mechanical noises no matter how hot the signal you send to the inputs. As can be seen even with a nominal 115dB sweep there is only about 2dB of output compression above 45Hz. By the 120dB nominal sweep the 1500X is finally at its maximum output potential across the entire 10-120Hz bandwidth. Judging by the compression shape in the deep bass the internal boost equalization appears to be at least 12dB if not even more, centered at 22Hz! Even at this 100% maximum output level the 1500X was very well behaved and while there was some deep bass distortion audible as warmth or an overtone to the measurement signal, otherwise the cabinet did not rattle or buzz and there was none of the spurious mechanical or other signals from the driver that it was badly overdriven as with many other units. The types of bad overload noises mentioned do not show up obviously in harmonic distortion measurements because they are not noises that are harmonically related to the signal but are actually far more subjectively obvious and offensive to the ear because of this fact. These are things like port chuffing, driver mechanical bottoming, or suspension slapping and rattles or buzzes in the cabinet or grille. The 1500X exhibited none of these. This is a very well protected and bullet proof design.

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 MartinLogan Dynamo 1500X: Total Harmonic Distortion

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MartinLogan Dynamo 1500X: Distortion by Component

The distortion results for the 1500X indicate that it behaves well during the 100dB sweep but as previously seen is already being driven to maximum output near 20Hz which shows up as elevated deep bass distortion. Above 35Hz there is less than 5% THD at that drive level. By the 120dB nominal sweep the deep bass is into the limiter, the amp is out of headroom everywhere and the deep bass distortion has grown to over 30% below 25Hz. Still the THD is just reaching 10% above 40Hz while the output is above 110dB. Looking at the harmonic makeup of the distortion captured during maximum output of the 1500X shows that while distortion is not extremely low it is primarily dominated by the 2nd harmonic over almost the entire range above 23Hz. The 2nd harmonic is relatively benign subjectively and indeed some listening tests have shown people to prefer a bit of 2nd harmonic distortion. Again this confirms my impression of the 1500X sounding very composed even when pushed very hard. The third harmonic, indicating large driver excursions usually, becomes highest between 14Hz to 23Hz but drops off dramatically above 30Hz. The 4th harmonic is under 3% above 19Hz with the 1500X producing its maximum output.

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MartinLogan Dynamo 1500X: CEA2010 2 Meter Groundplane RMS Results

CEA2010 Results

The CEA2010 maximum distortion limited short term output results for the Dynamo 1500X indicate that it has impressive headroom from 40-100Hz, with peaks of 110-115dB recorded. This is the range where most of the bass in music is centered. This reaffirms my subjective impression of the 1500X of doing especially well with music. In the deep bass the 1500X loses some steam as is to be expected of a small sealed subwoofer…The physics is simply against it having huge deep bass output. However it still produces respectable output by using a capable 15” driver and strong amplifier and manages to dish up 90dB way down at 12.5Hz. It could not quite produce 100dB at 20Hz at 2 meters, topping out at about 98dB with the CEA-2010 burst signal. In room however the typical boost to frequencies below 30Hz will help provide some extra headroom in the deep bass and indeed measurements in my room at the listening position indicated that the 1500X received a nice lift from the room and that distortion was also lowered substantially. Considering the design and overall size of the 1500X these are commendable results.

 

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Recent Forum Posts:

everettT posts on February 10, 2018 15:57
AVphile, post: 1233076, member: 17100
So can you confirm 1500X is made in Canada? I thought only the Balanced Force and ESL subs were, and entire range of Dynamos were China, but this might actually make sense since it has PBK and the smaller Dynamos don't.
Why does it matter if they are made in Canada? SVS Canada and Funk Audio should be your choice for higher end.
theJman posts on February 10, 2018 15:22
You do realize this thread has been inactive for 2 1/2 years, right?
AVphile posts on February 10, 2018 14:14
copmagnet82, post: 1012413, member: 68154
2 months later, but…

when you factor in the fact that 1500X is made in Canada and not China

So can you confirm 1500X is made in Canada? I thought only the Balanced Force and ESL subs were, and entire range of Dynamos were China, but this might actually make sense since it has PBK and the smaller Dynamos don't.
DaMaster posts on August 15, 2015 14:39
Cant tell by the pictures which OEM manufactures their woofers. Looks like a Dayton or Morel cone but the frame is different .
copmagnet82 posts on January 23, 2014 04:33
shadyJ, post: 994028
I don't know what you are looking at but the SB12 does not approach the output of this sub, it looks like the ML maintains about an average 5 dB lead over the SB12 across the entire measured frequency range. You would need at least two SB12s to match a single 1500X. I don't think this sub is a bad deal when you consider its size, and remember the street price is likely to be lower than the MSRP.
2 months later, but…

I just wanted to second that. I'm in the market for a sub now, and I don't know why some people don't give this sub the credit it deserves. It seems like the general consensus is that if it is not a SVS sub, it is not an good sub. Don't get me wrong, SVS, Hsu, Rythmik and other internet companies have great products, in fact if I wasn't getting the deal I'm getting on 1500X, I'd most likely get a SVS sub, but even then a comparable SVS sub is SB13-Ultra, which is the price of 1500X (albeit in satin black finish vs piano black), so it's really not as overpriced as some people say it is. Also, when you factor in the fact that 1500X is made in Canada and not China like SVS and some of the others (which is probably the reason for a higher price of the 1500X), then I really don't think it's that bad of a deal …and of course I'm not implying that Canadian made subs are better than Chinese ones, but I'd rather pay a little more and support North American economy (…and I am not Canadian ).

my $0.02
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