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Monoprice Monolith MTM-100 Measurements and Conclusion


The Monoprice MTM-100 was measured at a height of 4 feet at a 1-meter distance from the microphone, and the measurements were gated at a 4.5-millisecond delay. In this time window, some resolution is lost below 600 Hz and accuracy is completely lost below 300 Hz. Measurements have been smoothed at a 1/24 octave resolution.

MTM100 Spinorama graph 

The above graph shows the direct-axis frequency response and other curves that describe the MTM-100’s amplitude response in a number of ways. For more information about the meaning of these curves, please refer to our article Understanding Loudspeaker Measurements Part 1. The results shown here are surprisingly good. Much of the midrange is very nicely flat. There is a small on-axis dip centered at 4kHz which might soften the upper harmonics of female vocals and some musical instruments, but it is ameliorated at off-axis angles. The tweeter does get a bit rocky above 9kHz, but even then the general levels are about the same as lower frequencies on average, so I don’t expect this speaker to sound odd at high treble frequencies. The early reflections curve is very neutral and quite good. That means that the MTM-100’s acoustic reflections have good correspondence to the direct sound from the speaker.  The sound power response shows a bump centered just below 4kHz, and this would be due to the vertical off-axis nulls caused by the MTM driver arrangement. The horizontal off-axis behavior matters a lot more, and that is where this speaker shows much more neutral performance. Most desktop speakers intended for casual listening do not have this level of accuracy or anywhere near it.

MTM100 3D waterfall response 

 MTM100 2D waterfall response

The above graphs depict the speaker’s lateral responses out to 90 degrees in five-degree increments. More information about how to interpret these graphs can be read in this article: Understanding Loudspeaker Review Measurements Part II. The MTM-100 controls the response behavior extremely well, both on and off-axis. I am assuming the response was shaped by the DSP. One indicator that DSP is being used to shape the response is the slight upper treble raggedness, where the off-axis response starts to lose correlation with the on-axis response. Equalization can’t really fix that kind of problem, but it is pretty mild on this speaker. Most audio content lives below 8kHz, and in that region, this speaker performs beautifully, better than many studio monitors that I have dealt with in fact. Above that, it still does well, just not perfectly. I would guess that the waveguide is responsible for some of the slight off-axis jaggedness in upper treble, but it is so minor that I doubt it would have any audible impact on the sound. It is only of interest for academic curiosity. These graphs reflect what I heard in my listening demos: a neutral, balanced sound.

MTM100 Polar Map

The above polar map graphs show the same information that the preceding graphs do but depict it in a way that can offer new insight regarding these speakers’ behavior. Instead of using individual raised lines to illustrate amplitude, these polar maps use color to portray amplitude, and this allows the use of a purely angle/frequency axis perspective. The advantage of these graphs is they can let us see broader trends in the speaker’s behavior more easily. For more information about the meaning of these graphs, we again refer the reader to Understanding Loudspeaker Review Measurements Part II.

Above 1kHz, we see a very nicely even dispersion from the MTM-100. The dispersion stays fairly even and only narrows a little bit from 50 degrees to 40 degrees as we move up in frequency. It isn’t perfect, but it is amazingly good considering this speaker’s intended application. The tweeter doesn’t start to aggressively beam until just below 20kHz, and that is very good considering it is a 1.25” dome. The waveguide must be helping out to preserve the dispersion out to such a high frequency. Normally, dome tweeters in that size start to narrow in dispersion heavily above 9 or 10kHz. The bottom line on this graph is that the MTM-100s cover a fairly wide listening area with an even response, so these speakers should have a good tonal balance over a wide area.

MTM100 3D waterfall vertical response 

The above graph shows the MTM-100’s response behavior along its vertical axis where zero degrees is directly in front of the tweeter, negative degree values are below the tweeter, and positive degree values are above the tweeter. As would be expected of an MTM driver arrangement, the two woofers do start to bicker at off-axis angles. The good news is that the off-axis behavior on the vertical axis isn’t as important as the horizontal behavior, at least from the point of acoustic reflections. That being said, this graph matters more for desktop speakers or speakers intended for near-field listening than typical stand-mount speakers, because the direct sound from the speakers is going to have a greater impact on the listening experience than if the listener were seated far back. What is more, listening height can change much more relative to the speaker than further back or mid-field listening like in a normal living room or home theater setup. For example, if you set up the desktop speakers so the tweeter is level with the listener’s ears when seated at an upright position, the listener could be significantly far off in the vertical axis if they slouch or change their posture. The off-axis cancellation lobes caused by the two woofers are not as constricting in the MTM-100s as it is in some MTM-style speakers that we have seen, and that is because the woofers are not mounted very far apart. That does give the listener some flexibility on the vertical angle before the off-axis nulls start to mess up the response.

MTM100 Polar Map vertical 

The above graph shows the MTM-100’s vertical response in a polar map. The most important feature to see here is how wide of an angle the listener has before the cancellation nulls take their toll. The answer is good: users have about a +/-20degree angle from the on-axis response before the response starts to incur nulls. That is definitely better than average for an MTM speaker. As I said before, I don’t normally encourage readers to look at MTM speakers for desktop applications, but in this case, I will make an exception, because that kind of dispersion should cover a reasonable range of listening heights for a near-field environment. In other words, you don’t have to keep your head at an exacting height for these speakers to sound good, and you have a 20-degree angle above and below the tweeter that you can listen at before the sound takes on any significant changes.

Eagle-eyed readers might see that while the measurements are very symmetric above and below the on-axis response, they aren’t an exact match. That is because this speaker’s enclosure is slightly longer on the bottom than the top. That does cause a different pattern of diffraction and reflection from the cabinet from both the top and bottom but just barely. This isn’t of any audible concern but rather just an interesting feature to note for hardcore speaker nerds. 

MTM100 Low frequency Response 

The above graphs show the MTM-100’s low-frequency responses that I captured using groundplane measurements (where the speaker and microphone are on the ground in a wide-open area). The response here is good overall. We can see the tuning frequency of the passive radiator is about 60Hz. In my listening, I heard strong bass down to about 50Hz before the sound rapidly lowered in output. This is very good considering the size of these speakers. I can’t quite call these speakers full-range, but most users will be pretty happy with that kind of extension.

Users who want to add a subwoofer from the MTM-100’s own subwoofer output might want to try a 60Hz crossover on the sub so there won’t be much overlap between the sub and speakers, although given the way that normal room acoustics screws up the low-end response, there is no sure thing here (at least without measurements from the user’s own room). I would encourage users who utilize the MTM-100’s subwoofer output to experiment with different crossover frequencies on the sub and keep whichever setting sounds best to their ears.


Let’s quickly go over the strengths and weaknesses of the MTM-100s before bringing this review to a close, and let’s start with the weaknesses as we usually do. There isn’t a whole lot to complain about with the MTM-100s. I do think the build quality could be a bit more robust. I wish they would have added some interior acoustic damping or bracing. I understand there isn’t much internal surface that they could have mounted bracing or stuffing, but I think that some clever engineering could have solved that. The speakers sound good without it, so I wonder how much of an improvement that would have yielded.

MTM100 desktop7

One drawback to these speakers that wasn’t a problem for me but might present a problem for some is their sheer size for desktop speakers. Most desktop speakers are quite small because manufacturers know that a lot of people don’t have much free desktop space. There will be many people who simply cannot fit these speakers on their desktops. While the MTM-100s are larger than almost any other consumer-type powered desktop speaker, it does have a smaller footprint than many studio monitors, so it does split the difference between those styles of powered speakers.

MTM100 single3One addition that could have increased the value of these speakers is balanced analog inputs whether ¼” or XLR. I know that those inputs are geared more toward professional applications and the MTM-100s is intended for consumer applications, but its performance is certainly good enough for prosumer applications. The inclusion of balanced inputs would have made these speakers even more versatile, and they could be used with the many hundreds of professional or prosumer audio interfaces out there.

There isn’t a lot else that I could fairly complain about, so let’s move on to these speakers’ strengths. The first thing I have to compliment these speakers on is the sound quality; it was much better than I expected. As we said before, many consumer-level desktop speakers are pretty bad. The sound that the MTM-100s make isn’t just passable, it is actually very good. There are much more expensive hi-fi speakers as well as studio monitors that do not match their tonal accuracy. The excellent tonality extends over a fairly wide angle of the speaker’s dispersion as well. You don’t need to have your head fixed in a single location with a vice for these speakers to sound good. The bass extension is very good for the size of these speakers; they are pretty capable down to 50Hz. That is deep enough to cover the bass in almost any acoustic recording and a lot of electronically produced recordings as well.

The MTM-100’s dynamic range is overkill for desktop speakers. This is the opposite of so many other desktop speakers which are anemic. One advantage of the extra dynamic range is that these speakers will never strain under normal or even spirited listening levels. The MTM-100’s can be driven to the point of compression and distortion, but by that point, the listener’s ears would be bleeding in near-field listening. In fact, I think these speakers are more suited for a family room or bedroom system. They are too big for many people’s desktops but do have a good size for an audio system in a small-to-medium-sized room. All they would really need for that is the addition of a grille. These would be a lot better than most soundbars that can be had for the same price. And they can be used more easily for different sources than a soundbar. They are only missing an HDMI input for that kind of use, but, as we mentioned earlier, an HDMI audio extractor can be added fairly easily and inexpensively. Those who want deep bass for movies and heavy-duty electronic music can easily add a subwoofer via the MTM-100’s subwoofer output (any of the subwoofers mentioned in our article The Best $500 Powered Subwoofers for 2023 would be a great choice to compliment these speakers).

MTM100 pair11

The MTM-100 is basically a very good all-in-one audio system for $500. It’s perfect for people who want to skip an AVR and are looking for something simple and small but still sounds good. It’s fine for desktop use, at least for people with the desk space who can accommodate its footprint. It’s a great choice for those who want a decent stereo system but live in a very confined space like a small apartment or a dorm. Whoever designed the MTM-100s could have phoned in the sound quality part, and I think many of the buyers would still have been satisfied because few people expect high-fidelity from speakers in this product class. The engineers didn’t do that for these speakers and instead opted to make a fairly accurate loudspeaker. I really like that aspect of the MTM-100s and hope that kind of effort gets rewarded with success. These are good speakers that are a great solution for a variety of circumstances, and I am sure many buyers will be delighted with how well they perform.

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
Build QualityStarStarStar
Treble ExtensionStarStarStarStar
Treble SmoothnessStarStarStarStar
Midrange AccuracyStarStarStarStarStar
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStarStar
Dynamic RangeStarStarStarStar
Fit and FinishStarStarStarStar
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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