Speakers for leading edge, transients, speed and big sound

That kind of money would get a decent horn-based custom speaker from Deja Vu Audio.  This is a dealer that also builds high efficiency speakers utilizing a mix of new and vintage parts.  The better systems utilize horn compression drivers from the 1920’s through the 1960’s and horns from the same period.  Woofers are either vintage or custom new woofers specifically made for Deja Vu Audio.  At this price level, it is worth a trip to the Washington DC area to hear some of these systems.  You will also find that they make terrific tube linestages, amps and DACs too.

I heard, and liked the Moab.  It is a well balanced system with decent dynamics at modest listening levels (the real test of dynamic capability is how lively the speaker sounds at low levels0.  The JBL K2 is very dynamic sounding and is very good, although not as full and rich sounding as I personally like.  Klipsch speakers are decent, but, modern horn compression drivers and modern horns are not as good as the very best vintage ones, with the exception of some ultra expensive drivers from companies like G.I.P. and Goto (single drivers can blow this budget).  Avantgarde Uno or Duo are quite dynamic, but the bass is not that well integrated with the rest of the sound; still it is a good candidate for a used system.

Charney Companion with the AER driver option is a terrific choice.  Songer makes a fieldcoil driver system that is also very dynamic and big sounding.  The Fyne F1 coaxial driver system also might be a candidate.

Some speakers with big woofers don’t actually go extremely low because they have low excursion (the cone does not move very far back and forth).  These designs prioritize clean and fast response.  I prefer this kind of bass.

The low excursion drivers employ different kinds of surrounds, such as pleated fabric surrounds that sound cleaner to me, particularly at the upper end of the range the woofer is playing.  I suppose there are technical/theoretical explanations why woofers sound as they do (e,g, low excursion woofers have much lower doppler effect frequency modulation), but I don’t know why but they often do sound good to me.  Yes, iI hear plenty of good sounding systems employing small high excursion drivers, so  I am merely saying that I like many of these old school woofers, not that any design is always better.

I like the sound of the K2's but, this being a matter of personal taste, I don't think they are the best sounding horn-based systems.  The overall tonal balance is, for me too light in upper bass/lower midrange such that it is a touch thin sounding as far as my ideal speaker is concerned.  But, it certainly is a worthy candidate for consideration and might more completely fit someone else's taste preference.  

For some ionic tweeters, like the Hill Plasmatronic, a chemically inert gas was injected around the electrode to prevent it from corroding in the highly reactive environment of an ionized plasma.  Even with such gas protecting the electrode, it would get eaten up by that harsh environment.

Phusis,

Many good points are made in your excellent posting.  It would indeed be challenging for a big woofer to handle frequencies up to 700 hz.  A local builder uses quite sizeable horns and compression drivers that can go extremely low.  I recently heard a system where the crossover from compression midrange to woofers was set at 180 hz with a very shallow 6 db/octave slope.  The compression drivers were quite pricey, and if this were my system, I would insist on a higher crossover point and/or a 12 db/octave slope.  The woofers are twin 18” woofers made to his specifications.  The manufacturer insists on a minimum order of 40, and in the past three years or so, he has made three such orders.