MonAcoustic PlatiMon Virtual Coaxis One: Megabuck build quality for just $65,000?

With truly superb build quality, the PlatiMon Virtual Coaxial Single-Stand Speakers ($6,500 per pair, including stands) are the latest offering from MonAcoustic. Check out our review on YouTube.
Marty McFly once said, “The best things come from Japan.” When I was a child it was like that. I had a Sony Walkman (and later a Discman). No other brand can do this. My friend Arab has a huge Sony Trinitron TV, and my friend Ben has a Denon speaker that I’ve always dreamed of. Speaking of cars, my dream garage would have Marty McFly’s 1985 Toyota SR5 Xtra Cab pickup, which I use to tow a 1967 Toyota 2000GT to the track. When my friend Todd’s father got a Lexus, the neighbors were jealous. I certainly couldn’t imagine that 30 years later I would be saying that the best things come from Korea. But here we are. If you still prefer portable audio, your best bet is the South Korean Astell & Kern Digital Audio Player (DAP). Korean brands Samsung and LG are now the biggest names in a television industry no longer dominated by Japanese companies. When I was a kid, I thought Hyundai was just a knockoff Honda. But in today’s EV market, the Hyundai Ioniq 5 and Ioniq 6 consistently rank as the most attractive and reliable models, far ahead of Toyota and Honda EVs. (If you like Doc Brown’s DeLorean, you might also like the modern N Vision 74. It looks cool!)
Is home audio an area where South Korea will become the next dominant force? Recently, Korean brand HiFi Rose has been making waves with its high-performance, stylish streaming DACs and integrated amplifiers. If you’re looking for a more sophisticated approach to network audio, SOtM Audio is a popular Korean company that offers niche, multi-product solutions focused on maximizing audio quality. This brings us to MonAcoustic, a relatively new speaker manufacturer founded in 2020. The name “Mon” refers to a “more natural” sound, which has always been the main goal of the company’s founder and chief engineer, Jeon Hyeug Seo. A student of mathematics and topology, Jun developed a fascination with audio from childhood, listening to tube amplifiers in Korea in the 1970s. As a musician, he paid special attention to the timbre and sound of his instrument.
My hope is that people will find the right MonAcoustic product for their high quality jazz sound: the thickness of the cymbals, the natural sound of the horns, the sound of the piano, the sound of a nylon guitar – with the right harmonies.
The first two MonAcoustic models are the SuperMon Mini ($2,000/pair) and SuperMon Isobaric ($25,000/pair), both launched at Axpona 2022. Both have received official reviews on Audioholics. Today we get our first look at the company’s newest product, the PlatiMon Virtual Coax ($6,500 per pair, including brackets). Audioholic boss Gene DellaSala introduced the speakers when they were launched at the 2023 Florida Audio Expo, and our friend Shane Lee recently produced a video review of these new speakers for the Audioholics YouTube channel. Unfortunately, I was out of town when MonAcoustic US CEO Yong Byung held a listening session at a local dealer in May 2023 to demo the PlatiMon VC One and SuperMon Mini speakers, so I missed the opportunity to hear them in action. YouTube commentator Jay Lee of Jay’s iyagi channel recently interviewed Jeon Hyog Seo about PlatiMon Virtual Coaxis One, and I’ve included translations of some of Jun’s answers below.
The PlatiMon is a two-way “virtual coaxial” floorstanding loudspeaker with a vertical MTM design. Two 5-inch midrange drivers are located above and below the AMT (Air Motion Transformer) tweeter in a thin, perforated aluminum enclosure that measures 17 inches tall, 7.5 inches wide, and 10.6 inches deep. Each speaker weighs 32 pounds, not including the thick aluminum stand. The cabinet is reinforced with 6061 aluminum for “transparent, modern and clear sound.” The quality of the finish is first class, thanks in part to the “Super Brushing Technology” which provides a premium finish.
This is probably the most advanced speaker I’ve ever used at home. The seams line up perfectly and I’m confident this (aluminum cabinet) will stop a bullet.
MonAcoustic calls the PlatiMon Virtual Coaxis One “a true marvel of product design for high-end audio consumers.” Our goal was to develop a speaker that was larger and more powerful than the interestingly sized SuperMon Mini, but more affordable than the flagship SuperMon Isobic. The new speakers also had to be more efficient so that they could be easily controlled and produce natural sound on almost any amplifier. Although the PlatiMon’s nominal impedance is 4 ohms, the speaker’s sensitivity is much higher – 91 dB – than its peers. MonAcoustic recommends using 50 watts or more for best results, but 30 watts may be sufficient in some rooms. The speaker is reported to play at frequencies as low as 45 Hz, with high-quality extensions reaching up to 28 kHz.
The AMT tweeters that handle these high frequencies are designed in-house but manufactured in the USA to MonAcoustic specifications. According to the company, it can handle all frequencies above 3100 Hz. The tweeter is located inside a wide contour waveguide milled into a beautiful aluminum baffle. The 5-inch midrange driver is made in Germany and reportedly uses special neodymium magnets. According to MonAcoustic, the speaker drops smoothly to 53Hz and then begins to fade out.
The PlatiMons have enough resolution close to perfection that I can still hear the sizzle of cymbals or the click of lips captured closely with a microphone on a well-recorded track without it being too harsh or bright or too warm and sunken. . When positioned correctly, the image is very accurate.
The two rear ports are said to have received “unique sound pressure measurements,” a process that has led to some interesting design decisions. While you can’t tell the PlatiMons apart, each pair has separate left and right speakers located at the rear of the cabinet. The lengths of the two portal tubes are different, and the use of internal absorbent material is also asymmetrical.
The aluminum body is covered with leather and foam to eliminate resonance problems, especially in the 1 kHz range. I love leather upholstery in cars, but this is perhaps the first speaker of this level of luxury that I have encountered.
The result of all this asymmetry is “a deeper soundstage and unique width of sound,” says Jeong Hyo-seo. “Most speakers are interchangeable left and right,” he explains. “I tried this unique setting on the rear ports and internal network, which affects three resonances: port resonance, cabinet resonance, and driver sound.” According to MonAcoustic, June emphasized attack time, careful balance of hold time, and release time in his sound signature.
This careful approach to resonance control extends to the included “resonance decoupler bracket,” which uses ball bearings to separate the speaker from the bracket. The wiring inside the speaker is made by Korean brand Sanctus using 210 annealed wires twisted seven times.
Audioholics reviewer James Larson had the opportunity to hear the PlatiMons at Axpona 2023 after reviewing the $2,000 SuperMon Mini and $25,000 SuperMon Isobarics. Here’s what he had to say:
At $6,500 a pair, the PlatiMons hope to fill that (price) gap nicely by being a full-size bookshelf speaker without the over-the-top design of the SuperMon Isobarics. It still uses a great all-aluminum chassis, and one aspect that helps keep its price down is that it avoids the dual-woofer isobaric bass loading found on its other MonAcoustic siblings. Instead, it uses a more traditional bass loading port design. It uses an MTM design that places the sound lobe entirely in the center of the tweeter, so one of the key design decisions they made was to make the distance between the woofers as short as possible. This is a smart move that other growers can learn from as it allows for wider vertical dispersion. Many MTM designs place the woofers far apart, resulting in a very narrow optimal listening height, creating a null point when listening above or below the tweeter, eliminating large frequency response in important ranges. The sound produced by the PlatiMon is excellent and rich in detail without hiss or harshness.
When asked about the “virtual coaxial” aspect of the PlatiMon speakers, Jeong Hyog Seo said:
I like KEF, Tannoy and Fyne Audio speakers. Love them all. These speakers are typical coaxial speakers. Virtual coaxial speakers provide improved staging and are better suited for orchestral performances with a large number of instruments. Additionally, you cannot use AMT tweeters in a regular coaxial setup. I like the clean, transparent fluidity. For more precise staging and greater depth, you hear proper panning with proper left and right harmonics.
When asked about the use of aluminum housings and MonAcoustic’s unique damping materials, June responded:
Aluminum has special resonant characteristics that provide a cool sound. We take advantage of aluminum (but) use aluminum to achieve a more natural… warm sound. …There is wood from Africa called Mpingo wood. This is a rare and expensive material. I used to make speakers out of Mpingo wooden cabinets. The way we make aluminum speakers has the same sonic character as the Mpingo speakers I’ve built before. To reduce the resonance of the SuperMon Isobaric, I treated the inside of the body with a special and expensive leather material. I also used acoustic foam to reduce the negative sound signature of the aluminum. Inside the PlatiMon I used a special leather treatment.
Considering how much Shane Lee likes the work of the PlatiMon Virtual Coax One, I’m looking forward to hearing them in person and hopefully persuading James Larson to do an official review as well. Jung Hyo-seo says he plans to add larger speakers in the coming years, including what he calls “tall boys,” by which I mean floor-standing speakers. Interestingly, Jun also stated that he plans to manufacture future MonAcoustic models in the US. Are you more interested in MonAcoustic speakers made in the USA? Could South Korea be the next hotbed of audio innovation? Share your thoughts in the related forum post below.
With truly superb build quality, the PlatiMon Virtual Coaxial Single-Stand Speakers ($6,500 per pair, including stands) are the latest offering from MonAcoustic. Check out our review on YouTube.
Unless otherwise noted, this is a preview of the product presented. There may or may not be a formal review in the future.
Jacob is a music lover and audiophile who enjoys convincing his friends to buy audio equipment they can’t afford. He is also a freelance writer and editor based in Los Angeles.