Best Loudspeakers for Rich Timbre?

@duckworp
I am a Fanboy of good engineering. Unfortunately, in our hobby, and particularly high-end loudspeakers, they are hard to come by.
  
BTW, I travel a lot to Europe, and I am familiar with the foreign audio press. Don’t kid yourself; they are just as “colored” as the one in the US; try to find a bad review of a high-end German product in a German magazine, or a UK made one in a UK magazine, good luck ;) 

After weeks of waiting I finally got to visit The UK Audio Show 2018 (Woodland Grange, UK) at the weekend. They had some impressive speakers there including the curvy, strokeable Vivid Kaya 90 - amazing dynamics, scale, imagery and dare I say it, the merest hint of metallic tinged timbre? There were many other designs such as the organic sounding large bookshelf Audio Notes (AN-K) and some small bookshelves in the Malvern Research Audio room filling the room with Abbey Road via vinyl/tubes which begged the question - where have you hidden the subwoofer? The Arcadis EB2s sounded impressive and clean but a touch thin until I sat sightly further back. Then the sound became satisfyingly well balanced.

It was a thoroughly enjoyable show with plenty of tea and coffee stations close to hand. Many of the dealers and designers were willing to take requests to escape the usual tinkly piano Jazz. So we got to hear the Beatles (Norwegian Wood, Girl), Beethoven (piano), Donovan (Sand and Foam), Steely Dan (Babylon Sisters), Diana Krall (Temptation), Peggy Lee (Fever), Dire Straits (You and Your Friend) amongst others. Sources included vinyl, CD, and quite a lot of streaming via phone. All of them sounded good, with vinyl often sounding close to CD, clean with very low surface noise.

As good as the various designs were there was only one loudspeaker there that left me unable to find any fault sonically, and that was the Kerr Acoustic K320 (https://www.kerracoustic.com/k320)

Presented in a garish blue firing down a fair sized room, about 10 x 5m with a large window behind them, it was simply delightful in the way they played different genres of music - with all the tonal/timbral colour intact. They remained engaging and surefooted throughout the entire frequency range at both high and low volume, and had probably the cleanest treble I have ever heard from any loudspeaker.

Just a beautifully attractive colourful sound. Easily the best in show for me, and that included it's bigger brother the K100 which I felt was reference quality impressive in scale and dynamics (reminding me of the Naim Ovator 6000) but altogether more monochromatic than the always enjoyable K320s.

In fact I can't say I have ever heard a better sounding or more enjoyable loudspeaker at any show, and that includes Avantgarde Trio's and the similar sounding ProAc Future Ones.

It is not strange that after over a century of development that there is still no consensus amongst audiophiles as to which loudspeakers provide the greatest fidelity to the signal. Heck, some still believe nothing beats the wax cylinder for reproduction of the human voice.

What is surprising is the sheer diversity of designs, techniques and technologies. What began as a simple horn soon developed into the moving coil system followed by the electrostatic principle. Yet at each phase the new technology merely complimented the previous one rather than replace it.

For example we see moving coil drivers alongside BMR units alongside ribbon units and even plasma ones for treble.

We might see beryllium, polypropylene, radial, paper (doped/undoped), kevlar, aluminium, graphene etc all tried as cone materials amongst others such as hemp.

Then we come to the cabinets where we might find ultra rigid versus lossy designs, damped versus undamped, sealed box versus ported or transmission line designs. Sometimes there is no box at all as in open baffle or electrostatics. 

Cabinet materials might include MDF, Baltic Birch Plywood, aluminium, bamboo, or some form of composite design materials. 

Even the number of drive units can vary anywhere from just one to over a dozen. All this diversity begs the question of whether we are actually making any progress or are simply going around in circles? 

After all this time there's still so little that is commonly accepted and agreed upon by designers and loudspeakers still remain by far the weakest link in the audio chain as far as measurable distortion goes. 

So the choice of loudspeaker might therefore remain a choice of taste rather than a matter of one design being superior to another. Especially once cabinet effects and artefacts have been substantially reduced as we are beginning to now see even in relative budget designs such as the Q Acoustics Concept series.

As far as the search for timbre / instrumental colour goes there doesn't seem to be any consensus there either other than it probably depends upon primarily the drive unit material itself. And it's kind of reassuring that paper is still employed in many high end designs. 

It’s not any more surprising than the fact that people choose to wear different clothes, some styles more popular and enduring than others.

As good as the various designs were there was only one loudspeaker there that left me unable to find any fault sonically, and that was the Kerr Acoustic K320 (https://www.kerracoustic.com/k320)

Interesting; other than having a single mid-woofer instead of two in a D'Appolito configuration, this speaker is very similar to the Acoustic Zen Adagio which admittedly, is something of a classic performance-to-price bargain.