Vivid Audio Speakers

The unnatural voices of the Kaya prof mentions above (I have never heard vivid) probably has a lot more to do with the low side firing woofers with a high crossover point combined with the subtle rise in frequency response starting at 2k, just a guess. Probably makes for an odd acoustic center and makes that rise at 2-3k more noticeable. 

 The small bass drivers of the Kaya always seemed like a questionable design for such expensive speakers. I am a fan of displacement but always admired Vivid from a distance. The larger Giya models are way out of my price range. The engineering in them seems outstanding though. 
https://www.stereophile.com/content/vivid-kaya-45-loudspeaker-measurements

I don't mean they can't sound fantastic.

I remember being attracted in to a room at an AV show due to the amazingly "live" sound of a horn-based band track playing in the room...to find the vivid speakers playing.

I've also heard tracks like Genesis' Squonk sound astounding on the big Giyas - killer bass impact,  sonic detail, and imaging for miles.  I get why people like them, and they can no doubt sound convincing on the right material, or in the right set up.

I will preface this by saying I am a Vivid dealer who also sells Wilson Benesch and I make my own speakers from fiberglass and carbon fiber sandwich panels.

Because of the cabinet design materials and design, they are incredibly revealing.  It makes a huge difference.  That being said, amp matching really matters.  
The Kayas vs Giyas (Oval Decades are sold out) are different.  The Kayas are a bit warmer and less revealing than the Giyas.  Yes, I did a side by side of them.

They don’t need to be bright or metallic sounding.  You just need to use the right amp.  I have a customer running MSB amplification and it is jaw droppingly good.  AVM Ovation 6.3/8.3 amps are brilliant.  
It’s a combination of power and neutral/warm sound to be at the very best.  
I listen to a pair of Kaya 45s frequently.  Placement is incredibly easy and the only way I will get rid of them is to get a pair of G4’s.  I am driving them with an AVM A5.2 and they are awesome and natural.

They are not going to give you the sweetness and coloration of a paper cone.  If you really want that, then you should probably look at Kaiser.  Though they are very hard to place.  
Incidentally, since I design my own speakers using similar tech, I have a pretty good understanding how/why it works and am a big believer in it.

Have to side with prof and his impressions. I have immensely enjoyed listening to that 'extra' clarity of Vivid loudspeakers at RMAF over many years. And after the auditioning I have always been sure they'd be fatiguing over the long haul unless the amp was warm to warm+. 

Just my ears. Still a nice speaker and perhaps someone's ideal sound.

Been playing around with the Vivid Kaya 45s in our listening room recently.  Amplifier matching is critical but once you do, amazing.  If anyone heard them and says that they are not musical, please come to hear them in our room.  We could not stop listening to them this past weekend, 6 hours straight.  It took us a little bit to figure the set-up right but we are pretty amazed on the sound right now.