The SuperMon Minis are not typical stand-mount hi-fi loudspeakers. They are desktop/small space loudspeakers intended to be placed in a quarter-space acoustic environment. Therefore, the usual suite of measurements that we post is not really suited for evaluating them. Instead, we will post a few graphs that do demonstrate some of their idiosyncrasies as a guide to help users in optimally setting them up.

The above polar map graphs 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.  Perforated Rubber Surround

In the above graph of the horizontal dispersion, the most stand-out aspect is how much the tweeter’s frequency band is restricted compared to the woofer. This is about what I expected when looking at the speaker’s design: wide dispersion from the woofer and narrow dispersion from the tweeter. The narrow waveguide on the tweeter is really constricting the tweeter’s dispersion, so users will want to be within a 30-degree horizontal angle of the tweeter. Listening within that angle isn’t likely to be a problem in a desktop situation.

Positional Tip: An easy way to know if you are too far off-axis is if you cannot see all of the lettering in the word ‘MON’ printed on the tweeter plate, you are not going to be hit with much of the tweeter’s output.

The above graph is a polar map of the Mini’s vertical dispersion. The tweeter is the axial reference point, and positive degrees are angles above the tweeter with negative degrees being angles below the tweeter. The tweeter’s band above 5kHz produces an unusual result. The narrow waveguide is causing some complex diffraction and reflection patterns. The angles at which there aren’t any nulls occurring are ten degrees above and below the tweeter, so that is where users should ideally aim the speaker to hit the ears on the vertical axis. However, even if those exact angles cannot be managed, this type of interference pattern, called comb-filtering, isn’t tremendously audible. In my own listening, changes in height did produce a change in the sound, but unless the height differences were dramatic, such as standing up versus sitting down, the effect on the sound was not huge. One of the reasons that this disordered dispersion pattern is not easily audible is that these effects are restricted to treble frequencies where human hearing isn’t the most sensitive. The entire midrange band is very consistent on both the vertical and horizontal axis. Moreover, the type of acoustic reflections this pattern can produce can average out at the point of the listener’s ears, so the dips created by this response can be shored up by reflections from near vertical surfaces, i.e., the desktop. Nonetheless, there is room to optimize the sound by adjusting the vertical angle. If the treble seems a bit soft, simply angle the speaker up or down by a few degrees.

The above graph shows the SuperMon Mini’s low-frequency response that I captured using groundplane measurements (where the speaker and microphone are on the ground in a wide-open area). The most prominent feature is a bump at the port-tuning frequency of about 150Hz. This is probably what I heard as some thickness of the strings during my listening to the Kronos Quartet album. A lot of small speakers go for this type of voicing in order to make it sound bigger than it actually is, but it does color the sound, and I would prefer a more neutral response in that range. Curiously, the slope below that point rolls off at 12dB/octave slope, which is not normal for a ported enclosure. Usually ported loudspeakers roll off at a much steeper 24dB/octave slope below port tuning. I could only guess this is some kind of byproduct of the isobaric design since both woofers surround a sealed compartment. This is, however, not an unwelcome attribute, since it will do more to promote room gain which will shore up the low end thereby giving the user deeper bass extension than a typical ported roll-off.  Nonetheless, I wouldn’t expect much deep bass from this speaker, and the addition of a subwoofer did significantly improve the sound in my own listening. I would encourage a higher crossover frequency over the standard 80Hz as well for those who do choose to use a subwoofer with these speakers. Few speakers of this size will deliver much deep bass at all. The ones that do have a very limited dynamic range and can reach their limits very quickly. That is the trade-off that has to be made in a small loudspeaker; you can have dynamic range or low extension but not both. 

The above graph shows the electrical behavior of the SuperMon Mini. Mon Acoustics specs this as a 4-ohm speaker, and that is correct. The impedance and phase take on an unusual shape relative to other speakers, and I would attribute that to the isobaric design. The impedance minima dips down to just under 3 ohms and occurs around the crossover frequency between 5kHz and 6kHz. It is accompanied by a steep phase angle, and that can be a tough load for amplifiers. It is only alleviated by the fact that this low impedance and steep phase range starts at 4kHz which is just above the all-important midrange that is so heavily used by so many recordings. The other good news is that in a desktop environment, it’s not likely to get cranked super loud, so most amplifiers that are paired with this speaker aren’t going to be driven to the bleeding edge. All the same, I would not try to drive these speakers with a cheap, low-powered chip amp, not that anyone spending $2k on a speaker set is going to power them with a $75 amplifier.

I measured the sensitivity of the Minis to be 86.1dB for 1 meter at 2.83v. While that is a tad under Mon Acoustic’s listed sensitivity spec, this is actually a bit more sensitive than I would have guessed given the design. For a small speaker, 86.1dB is quite good. These speakers won’t need a powerful amp to get loud, especially for their intended application.

Before bringing this review to a close, I will briefly go over the strengths and weaknesses of the product under evaluation, and, as always, I will start with the weaknesses. While there is a lot to like about the SuperMon Mini, I do think there are a couple of aspects in which it could be improved. First, the response peak around the port tuning frequency could be toned down a tad. That voicing does make the Mini sound punchier but at the cost of a more natural sound. Most people would probably be fine with it and even prefer it, but I do think the overall sound of the Minis would be improved were that frequency band less elevated. Second, I would completely redo the waveguide on the tweeter. I would make it a lot shallower in order to simplify the tweeter’s dispersion and make it a lot less jumbled. To be fair, the speaker could be made to sound fine in actual practice without much fuss, but it is clear that waveguide design wasn’t something that Mon Acoustics was heavily invested in. The surprising thing about that there are many clever design decisions undertaken in the Mini as well as attention to detail, but somehow the opportunity for a better waveguide was overlooked. A more sophisticated waveguide will bring a more consistent sound over both vertical and horizontal planes. Mon Acoustics tell me that they are experimenting with new waveguide thicknesses, so future iterations of the Mini may well see improvements here. 

With those two complaints out of the way, I will now move on to the strengths of the SuperMon Minis. Firstly, the imaging was superb. I did most of my listening on a desktop system where I thought these would see most of their use by owners, and, as was mentioned before, a typical desktop environment is not an ideal acoustical space for a loudspeaker. Despite this disadvantaged placement, the Minis still managed to image very well and projected a superb soundstage. The tonality was fairly good; voices sounded lifelike, and music was always very clear and precise. Dialogue and lyric intelligibility were always top-notch. Something else I liked was that, despite the use of an AMT tweeter, the treble didn’t leap out to scorch my ears. Many manufacturers let their AMTs run a bit hot for some reason, but that wasn’t the case with the Minis. In fact, I would say these speakers are on the warmer side of sound voicing. If you aren’t a fan of aggressive treble, the Minis could have a very appealing sound to you. The dynamic range was fine and more than good enough for a desktop loudspeaker. Of course, users will have to keep their expectations in check; they don’t do deep bass, but that just isn’t realistically in reach of any speaker of this size.

Outside of their sound, the aesthetic of the speaker is very cool, and I think it will draw a lot of people in just by its looks. People who are going for a high-end desktop look are going to love the Mini, especially those in modernist office decor. They feel as solid as they look too; they have a solidity befitting of their pricing. They are a luxury item in every respect, and there are no shortcuts taken to cheapen the speaker. They are hand-assembled in Korea using Korean manufactured parts. Picking one up feels like holding a solid metal block. They may well have the highest build quality of any small speaker anywhere.

One aspect that their build quality leads to is longevity; these speakers could last a very, very long time. If cared for, the SuperMon Minis will last for many decades. They are a true heirloom product. The enclosure is obviously built to last, but there are other features of the design that leads to longevity. Firstly, AMT tweeters don’t have soft suspension components that can degrade over time, so they are not really susceptible to age-related degradation. In common crossover circuits, many types of capacitors can have their values drift over time, but not the giant metal film caps used in the Minis. Much like the enclosure and tweeter, the crossover circuit will not really age to any meaningful degree. The only components that are susceptible to age in the Minis are the rubber woofer surrounds. However, consider that only one side of either woofer is exposed to the environment due to the isobaric chamber, so it will only age half as quickly as a normal ported loudspeaker. If you want a beautiful speaker that will outlast you, the SuperMon Minis have the potential to do that. Furthermore, if you wanted to pass them down to someone else, they are not burdensome for many people to accommodate since they are quite small. The Mini’s durability and long life will probably be an advantage in terms of resale value as well in case owners ever wanted to sell them.

In the end, the SuperMon Mini largely accomplishes what it sets out to do, and I think that the vast majority of buyers will be very happy with what they receive. They are going after a niche market segment, but if you want a small but extremely high-end speaker, Mon Acoustics delivers here. Everyone that I showed it to were immediately impressed by its appearance and build quality, and they enjoyed the sound when I offered them a demo. They are pricey speakers, but if you want the best-built small speakers in the world, these would not easily be topped.  

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.

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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