The MonAcoustic PlatiMon Virtual Coaxial One: Megabuck Build Quality for $6.5K?

MonAcoustic PlatiMon Virtual Coax One Speaker

MartyMcFly once said, “All the best stuff is made in Japan.” That certainly seemedto be the case when I was a kid. I had a Sony Walkman (and later, a Discman).No other brand would do. My friend Alap had an enormous Sony Trinitron TV, and my friend Ben had a Denonboombox that I coveted ardently. When it came to cars, my dream garage includedMarty McFly’s 1985 Toyota SR5 Xtra Cab pickup truck, which I’d use to tow a1967 Toyota 2000GTto the racetrack. And when my friend Todd’s dad got a Lexus, it was the envy ofthe neighborhood. It certainly wouldn’t have occurred to me that, 30-somethingyears later, I’d be saying that all the best stuff comes from Korea. But herewe are. If you’re still into portable audio, the digital audio players (DAPs)from South Korea’s Astell & Kernare the best of the best. Korean brands Samsung and LG are now the biggestnames in a TV business no longer dominated by Japanese companies. When I was akid, I thought Hyundai was just a knockoff Honda. But in today’s electric carmarket, the Hyundai Ioniq 5 and Ioniq 6 are consistently rated among the mostappealing and reliable — streets ahead of the electric offerings from Toyotaand Honda. (And if you like the Doc Brown’s DeLorean, you’ll probably love the Hyundai N Vision 74. It looks so cool!)

Ishome audio the next area in which South Korea will become a dominant force?Recently, the Korean brand HiFi Rosehas made a splash with its high-performance, high-style streaming DACs andintegrated amplifiers. If you want a more granular approach to network audio,SOtM Audio is a popular Korea-based company offering niche,multi-product solutions with afocus on maximizing every ounce of audio performance. And that leads us toMonAcoustic, a relatively new loudspeaker manufacturer founded in 2020. Thename “Mon” refers to “more natural” sound, and that has been the main goal forcompany founder Jun Hyeog Seo, who also serves as chief engineer. A student ofmathematics and topology, Jun becameobsessed with audio at a young age, listening to tube amplification in SouthKorea in the 1970s. Also a musician, he pays special attention to the timbreand tone of instruments.

Iwant people to find MonAcoustic products for their high-end jazz sound: thethickness of cymbals, the natural brass sound, piano sound, nylon guitar sound— with the right harmonics.

—Jun Hyeog Seo

Thefirst two models from MonAcoustic were the SuperMon Mini ($2,000/pair) and SuperMon Isobaric ($25,000/pair), both introduced atAxpona 2022. Both have received formal reviews here at Audioholics. Today wetake a first look at the company’s newest offering, the PlatiMon VirtualCoaxial One ($6,500/pair including stands). Chief Audioholic Gene DellaSala gota sneak preview when the speaker was introduced at Florida Audio Expo 2023, andour friend Shane Lee recently did a video review of thesenew speakers for the Audioholics YouTube channel. Sadly, I was out of town andtherefore missed an opportunity to hear them in action when Young Byun, CEO ofMonAcoustic US, hosted a listening session demonstrating the PlatiMon VC One and SuperMon Minispeakers at my local dealer back in May 2023. YouTube reviewer Jay Lee of the “Jay's iyagi” channel recently interviewed JunHyeog Seo about the PlatiMon Virtual Coaxial One, and I have included some ofJun’s translated responses below.

ThePlatiMon is a 2-way “virtual coaxial”stand-mount speaker with a vertical MTM design. Two 5-inch mid-woofers sit above and below an AMT (Air MotionTransformer) tweeterin a slender, ported aluminum cabinet measuring 17 inches tall by 7.5 incheswide by 10.6 inches deep. The speakers weigh 32 pounds each, not including thechunky aluminum stands. The enclosure is reinforced with 6061-grade aluminum, promising“transparent and modern, clear sound.” The finishing quality is top-notch,thanks in part to a “hyper brushing technique” that ensures a premiumappearance.

Thismight just be the most exquisitely-made speaker I’ve ever had in my home. Theseams line up perfectly, and I’m positive this (aluminum cabinet) could stop abullet.

—Shane Lee

MonAcousticcalls the PlatiMon Virtual Coaxial One a “true marvel of product design forhigh-end audio consumers.” Thegoal was to design a speaker larger and more capable than than the fun-sizeSuperMon Mini, but with a more approachable price than the flagship SuperMonIsobaric. The new speaker would also need to be more efficient so it would beeasy to drive and sound natural with nearly any amplifier. Although the PlatiMon has a nominal impedance of 4 Ohms, the speaker’s 91dB sensitivityrating is indeed usefully higher than that of its siblings. MonAcousticrecommends 50 watts or more for best results, though in some rooms, 30 wattswill be sufficient. The speaker reportedly plays down to 45 Hz, with a top-endextension reaching 28kHz.

The AMT tweeter handling those high frequencies wasdesigned in-house but is made in the USA to MonAcoustic’s specifications. Ithandles everything above about 3,100 Hz, according to the company. The tweeteris placed inside a wide, chiseled waveguide milled into the meticulous-lookingaluminum baffle. The 5-inch mid-woofers are made in Germany, and reportedly usespecial neodymium magnets. The driver plays flat down to 53 Hz before beginningto roll off, according to MonAcoustic.

ThePlatiMons hit a near-perfect spot for having enough resolution so I could stillhear the sizzle of cymbals or the close-miked lip smacking in a well-recordedtrack without it being overly in-your-face or bright or too warm and recessed.And once I got the placement just right, the imaging was pinpoint accurate.

—Shane Lee

Thetwo rear ports were reportedly subjected to “unique sonic pressuremeasurements,” and this process led to some interesting design choices.Although you can’t tell from looking at the PlatiMons, each pair has a dedicated left andright speaker, designated on the rear of the cabinet. The two port tubes are ofdifferent lengths, and the internal absorption material isapplied in an asymmetrical way as well.

The aluminum cabinet is lined with bothleather and foam to address resonances, particularly in the 1kHz range. I enjoya leather interior in a car, but this might be the first speaker I’ve comeacross to boast that particular luxury.

The result of all this asymmetry is a“deeper soundstage, and unique sound width,” according to Jun Hyeog Seo. “Mostspeakers can be swapped left and right,” he explains. “I experimented with thisunique setup to the rear ports and to the internal network, which affects threeresonances: port resonance, enclosure resonance, and driver sound.” Junemphasizes in his sonic signature a careful balance of attack time, sustaintime, and release time, according to MonAcoustic.

This diligent approach toresonance control extends to the included “resonant decoupling stands,” whichuse ball bearings to decouple the speaker from the stand. The cabling insidethe speaker is made by the Korean brand Sanctus, and uses 210 annealed wires that have been stranded 7times.

Audioholics’ever-observant loudspeaker reviewer, James Larson, had a chance to hear the PlatiMons at Axpona 2023,after reviewing both the $2K SuperMon Mini and the $25K SuperMon Isobarics.Here’s what he had to say:

The$6.5K/pair PlatiMons look to fill that (price) gap nicely, being a full-sizedbookshelf speaker but without the over-the-top construction of the SuperMonIsobarics. It still uses a gorgeous fully aluminum cabinet, and one of theaspects that helps to keep its pricing down is that it eschews the isobaricdual-woofer bass loading that its other MonAcoustic siblings employ. Instead,it uses a more traditional ported design for bass loading. It uses an MTMdesign to center the acoustic lobe fully on the tweeter, and one criticaldesign decision they made toward this end was trying to minimize the distanceof the woofers. This is a smart move that other manufacturers could learn fromsince it allows for a wider vertical dispersion. Many MTM designs space thewoofers far apart, and that leads to a very narrow optimal listening heightwhere listening just a bit above or below the tweeter will induce nulls thattake chunks out of the frequency response in important ranges. The sound thatthe PlatiMon produced had excellent imaging, and it was detailed without beingsibilant or harsh.

—James Larson, Audioholics Loudspeaker Reviewer

Whenasked about the “Virtual Coaxial” aspect of the PlatiMon speakers, Jun HyeogSeo had this to say:

Ilike speakers from KEF, Tannoy, and Fyne Audio. Love them all. These speakersare typical coaxial speakers. Virtual coaxial speakers offer improved staging,which is more suitable to playing orchestral music with more instruments. Also,with a regular coaxial setup, you cannot use an AMT tweeter. I love the clearand transparent fluidity. For more accurate staging, with improved depth, youhear the right sound imaging with correct left and right harmonics.

—Jun Hyeog Seo

Whenasked about the use of aluminum cabinets and MonAcoustic’s unique dampingmaterials, Jun replied:

Aluminumhas a specific resonance signature that could be heard as a cool sound. Weutilize aluminum’s advantages (but) promote more natural… warm sound withaluminum material. …There is a wood from Africa called Mpingo wood. It’s a rareand expensive material. I have made a speaker using that Mpingo wood bodycabinet in the past. And the way we are making our aluminum speaker has thesimilar sound signature as the Mpingo cabinet I made in the past. To reduce theresonance in SuperMon Isobaric, I treated the inside with very special andexpensive leather material inside of the cabinet. I also used absorbing foamsto reduce the negative sound signature of aluminum. Inside PlatiMon, I used alittle of that special leather treatment.

—Jun Hyeog Seo

Consideringhow much Shane Lee enjoyed the performance of the PlatiMon Virtual Coaxial One,I’m looking forward to an opportunity to hear them for myself, and I hope thatJames Larson will be conducting a formal review as well. Jun Hyeog Seo hasindicated that he plans to add bigger speakers in the coming years, includingwhat he calls “tall boy” speakers, which I take to mean floor-standers.Interestingly, Jun has also said that he’s planning to build future MonAcousticmodels here in the United States. Would you be more interested in a USA-madeMonAcoustic speaker? Will South Korea be the next hotbed of audio innovation?Share your thoughts in the related forum thread below.

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.

Jacob is a music-lover and audiophile who enjoys convincing his friends to buy audio gear that they can't afford. He's also a freelance writer and editor based in Los Angeles.

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