Speakers for leading edge, transients, speed and big sound

I would definitely look for a pair of Acapella Audio Arts speakers. 

One of the best horn speakers available. 

They use a plasma driver for the tweeter, which could be the best tweeter available. There is nothing with better transient response than a tweeter with ZERO MASS!  

Amazing attack and decay.

At your budget, you would be able to get a great pair used. 

I have a question about the JBL K2 S9900.

TMR just listed a pair, and I was looking into it to see if it’s something I should be interested in.

According to their datasheet, bass extends to... 33 Hz @ -10 dB? Really? Are they some kind of Cerwin-Vega tribute? Lots of folks talk about them like they’re the second coming though, so what am I missing?

The AMT (Air Motion Transformer) and it's "derivatives" have excellent transient response.  It's a matter of whether the rest of the components can keep up.

I’ll definitely toss a vote in for Volti. I’m not a horn guy, per se, but I heard some large Volti speakers at AXPONA and I was kinda blown away. They were playing a Dean Martin recording and it did sound rather awesome. They landed in my “cost no object” top five speakers at the show. If I had the money and the room, I’d be listening to them right now. 
 

Dave

 If I had the money and the room....

a popular sentiment in our hobby