PlatiMon

Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Audirvana 3, Qobuz, Tidal, Singxer SU-6 USB bridge, LHY Audio SW-8 network switch, Sonnet Pasithea DAC; Active filter: icOn Gradient Box 2; Power amplifiers: Kinki Studio EX-B7 monos, Goldmund/Job 225, Electrocompaniet Nemo 800M [on review]; Headamp: Cen.Grand Silver Fox; Phones: HifiMan Susvara; Loudspeakers: Qualio Auido IQ + sound|kaos DSUB 15 on Carbide Audio footers, Audio Physic Codex; Cables: Complete loom of Allnic Audio ZL; Power delivery: Vibex Granada/Alhambra on all source components, Furutech RTP-6 on amps, Furutech DPS-4.1 between wall and conditioner; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands; Sundry accessories: Acoustic System resonators, LessLoss Firewall for loudspeakers, Furutech NCF Signal Boosters; Room: 6 x 8m with open door behind listening seat
2nd system: Source: Shanling M3 Ultra, Soundaware D300Ref SD transport, Cen.Grand DSDAC 1.0 Deluxe; Preamp/filter: icOn 4Pro + 80Hz active filter, Vinnie Rossi L2 Signature w. ER50; Amp: Enleum AMP-23R; Loudspeakers: MonAcoustics SuperMon Mini, Dynaudio S18 sub; Power delivery: Furutech GTO 2D NCF, Akiko Audio Corelli; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Sundry accessories: Audioquest Fog Lifters; Furutech NFC Clear Lines; Room: ~3.5 x 8m
Desktop system: Source: HP Z230 work station Win10/64; USB bridge: Singxer SU-2; Headamp/DAC: iFi iDSD Pro Signature;  Headphones: Final D-8000; Active speakers: DMAX SC5
Upstairs headfi/speaker system: Source: smsl Dp5 transport; DAC: Auralic Vega; Integrated amplifier: Schiit Jotunheim R; Phones: Raal-Requisite SR1a; Active DSP speakers: Fram Midi 120
2-channel video system: Source: Oppo BDP-105; All-in-One: Gold Note IS-1000 Deluxe; Loudspeakers: Zu Soul VI; Subwoofer: Zu Submission; Power delivery: Furutech eTP-8, Room: ~6x4m
Review component retail: $6.5K/pr incl. stands

Platypus platitudes in plated platinum? Down Under's egg-laying semi-aquatic mammal with the duck bill combines eclectic bits from various species. South Korea's latest MonAcoustic speaker once again relies on aircraft-grade 606 aluminium for its black or silver enclosure. Then it foregoes its precursors' isobaric bass loading. Instead it centers its US-made AMT tweeter with a 3.5kHz filter¹ between two 5" German mid/woofers. Designer Jun-hyeok Seo refers to it as a virtual coax so quasi Fyne, KEF or Tannoy but without their outer driver playing constantly moving waveguide for the inner one; not that his preferred pleated tweeter would lend itself to such loading in the first place.

Why the name PlatiMon is rather more mysterious. Hence my silly opening. Whilst unapparent to the eye to which they seem identical, these speakers are paired. As indicated on the back, one is left, one right. For best results, they aren't freely interchangeable. Can crossovers perhaps shape asymmetrical dispersion to make it wider on that side of a speaker which faces out not in? Conspiracy theories are always fun. At 15kg/ea and sold with matching stands whose top plates conceal decoupling ball bearings, a $6.5K sticker situates PlatiMon between $2.5K SuperMon Mini and $25K SuperMon. I was originally slated to review the big boy below. Its colossal weight and associated ship fees simply proved prohibitive.

Instead I reviewed then awarded the 4" 2-way mini and acquired it for my upstairs system augmented by my resident Dynaudio S18 sub. Already back then I knew that something bigger though still very much manageable was in the wings. That out of them would emerge PlatiMon with its deeply scalloped fascia for an even more deeply inset tweeter I obviously didn't. At the Florida Expo, Mr. Seo's North-American distributor Young Byun introduced audiences to the full MonAcoustic portfolio. His system made for an ideal size comparison even just looking at it. The hookup wiring for PlatiMon is Sanctus also from South Korea. Being a speciality firm embedded in a much larger enterprise with existing wire manufacturing, Sanctus are unusual in the hifi space for making their own conductors.
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¹ Readers familiar with the bandwidth of vocals and instruments appreciate how so high a filter transition runs these dynamic drivers as essentially widebanders. Only a few fundamentals in a piano's rightmost reaches plus certain high percussive noises occur beyond 3'500Hz. For most intents and purposes, that bandwidth is occupied by just overtones aka higher harmonics.

Photo credit: PartTimeAudiophile.

The current expansion strategy of MonAcoustic focuses on the US over Europe and even predicts eventual manufacture of certain models in the colonies. So so we should expect first PlatiMon reviews to emerge from there shortly. Once it's the EU's turn, I shall be happy to host a traveling PlatiMon pair in my two review systems. Until then, consider this a just brief teaser of likely good things to come. Put differently, the aluminator brigade of Magico, Stenheim and YG is gaining competition from the land of Kia/Hyundai and Samsung.

If you've never seen how an air-motion transformer based on the expired patent of Dr. Heil is made, this brief video from Berlin shows you. It drives home how large such a tweeter's surface is before the many folds narrow it considerably. The resultant air-squeezing action is said to give such designs a 4:1 even 5:1 velocity advantage over standard air-pushing dome tweeters. The video also shows how like for planarmagnetic membranes, voice-coil traces affix to the entire diaphragm which is often Kapton. That differs from true ribbons whose entire metallic diaphragm is conductive to require no printed traces. Calling an AMT a folded ribbon thus is a misnomer. Makers of AMT include Dayton, Elac, Gladen, GoldenEar, HEDD, Mark & Daniel, MartinLogan, Monacor, Mundorf, Precide and SB Acoustics. In my domestic speaker arsenal the Acelec Model One, MonAcoustic SuperMon Mini and Qualio IQ all use such tweeters, the latter even in dipole mode. To my knowledge only M+D make larger AMT which can cross over as low as 600Hz. Outright AMT woofers don't seem to exist at all so we're nearly exclusively seeing this type driver as a tweeter.

Elsewhere, PlatiMon's driver array is generically referred to as d'Appolito after Joseph d'Appolito who used the MTM array with originally a 3rd-order later 4th-order filter to correct the downward lobing of basic tweeter/mid-woofer designs without physical time alignment. There's more to it than just using two mid/woofers closely bracketing a tweeter. Given PlatiMon's time alignment, a true d'Appolito design wouldn't be necessary. It's probably why Mr. Seo calls it a virtual dual-concentric instead. The new Concept 50 from Monitor Audio pursues a similar thing whereby six 2" flat mids surround a central AMT like tightly clustered flower petals. Tekton Design too promote a tweeter surrounded by six more tweeters operated as mids. The Concept 50 and Tektons clearly approximate a KEF-type coax with individual drivers. PlatiMon's two-way seems to follow their three-ways with a simpler execution using just two mid/woofers for claimed 53Hz-28kHz response with 91dB/4Ω sensitivity packed into 17×7.5×10.6" HxWxD.

My upstairs SuperMon Mini in custom lilac faceplates. Stands by Q Acoustics.

Given my appreciation for Mr. Seo's baby speaker, I'm unsurprisingly curious about what he has wrought with his next one up. Stay tuned until I find out.

… to be continued when MonAcoustic join the EU…