PlatiMon VC1 basics. Twin 5" Berlin-sourced mid/woofers surround a small US-made AMT set deeply into a scallop with a 3.1kHz filter. The close-spaced MTM array has designer Jun call it a virtual coax, hence the VC suffix. The dual ports in the rear are of dissimilar length so each monitor is marked L and R to mirror-image the ports as intended. You may think it immaterial but it does make a difference. Whilst you could disagree with the designer as to which orientation you prefer, it's worthwhile to compare them to be sure.

Here we see the modification Jun makes to his driver's magnet; and how the internal layout of the VC1 monitor is asymmetrical not just with regards to its dissimilar port tubes but damping liner.

This photo shows the size of PlatiMon VC1 vs. SuperMon Mini…

… and this one SuperMon Mini vs. VC2.

Next a visualization of the VC1 in high-pass mode. Green shows its solo behaviour, red how it blends out far sooner in 4-way mode. Now some harmonic basics. The spread between a fundamental and its 16th harmonic is exactly four octaves. The highest fundamentals which acoustic instruments not synthesizers can generate are 4'186Hz (piano), 3'349.3Hz (flute) and 3'136Hz (violin). If we take the piano's right-most very rarely played key, its 2nd harmonic occurs at 8'372Hz, the 4th at 16'744Hz, the 8th at 33'488Hz and the 16th at 66'976Hz. In this scenario, a super tweeter covering 25-40kHz will reproduce the 7th to 9th harmonic of a piano's highest tone. Everything below it still falls to the standard tweeter. Anything above it remains out of range. By implication, all sounds of a lower pitch move downward this split of which driver does what. Now the harmonics which still fall into our super tweeter's range get successfully higher. For most intents and purposes, an ordinary tweeter good to 20kHz will suffice. Or so theory says. If we do hear a decisive difference as Jason did, the more interesting question than 'how' could be, just exactly what do we hear? Mon suggest more upper harmonics hence their 'harmonic tweeter' moniker even though we just learnt that on fundamentals up to 1'250Hz, a standard 20kHz tweeter already captures all harmonics up to the 16th. Jason meanwhile spoke of "significantly more air and ambiance". It's why other manufacturers refer to super tweeters as ambient tweeters. Which is it? Does it matter? Sometimes asking such questions overthinks Here I'll add Young Byun's suggestive comment that "our unit promotes even-order harmonics" even though I'm in the dark on how it can selectively disregard/filter out odd-order components unless it actually produces even-order harmonics.

Electronic circuits with predominant 2nd or 3rd-harmonic distortion remnants ideally don't produce anything beyond the 4th or 5th harmonic. This THD adds itself to the recorded signal to season it in subtle or more overt ways depending on distortion percentages. That speakers generate their own THD is always implied but published specs tend to not cover specifics. Young's even-order comment is thus interesting. Here's what Fyne say about their own super tweeter: "Each loudspeaker or audio device exhibits a low-pass filter function which acts as a frequency-independent time delay in the pass band otherwise known as linear phase response. To reduce low-frequency phase error, adding a subwoofer does more than add bass. Reducing this phase error is a main benefit of a well-integrated subwoofer. Music with no apparent bass content will sound more natural when this error is removed. Likewise, the addition of a time-aligned super tweeter reduces HF phase error by moving the low-pass point much higher. Even if we ignore hearing beyond 20kHz, the addition of a super tweeter better preserves the harmonic relationship between instruments which is apparent down to low frequencies. This important fact is simply not intuitive."