Seeking horn array loudspeakers with a maximum price of $17,500.00 per pair.

Another recommendation for Volti Rivals. I really enjoy mine. Not even sure that you will have to turn on your big Bryston amp to get to 60 db…. You might need 1/10 of a watt on peaks w/ them at 98+ db sensitivity. Seriously, some amps don’t sound their best until significant power is drawn from them so you may consider a lower powered amp & maybe tubes.

sounds rich, full bodied and dynamic at 50-55 decibel levels

I question if that is possible with any loudspeaker.

If I were in your shoes with that budget, my choice would be to take that dough and get a nice pair of custom veneer Volti Lucera's or a used pair of Rival's then spend the remainder on tube amplification. I had the Rogue RP-1 and liked it very much. Paired with something from Cary, or Quicksliver would be pretty awesome. I have yet to hear a loudspeaker that knocks dynamics, tonal quality, and midrange out of the park like Volti's do. IMO of course. 

Agree with @vicdior . The Fleetwood Deville. Did an audition recently. They are difficult to beat at that price point. Definitely something to go listen to. Some don't like their look however. Best of luck and keep us posted.

 You have some great choices at your price point, especially if you consider used.

Agree with ozzy62, I would not want your amp with horns.

Another Volti recommendation. But if I were you, I'd be looking at high quality SET amps to replace that Brightson......

Look at Joseph Crowe Audio. 

Most of my listening is at those volume levels and the sound is rich and full.

my amps are 4.5 watt monoblocks type 45 tubes.

I recommend the Fleetwood Deville SQ, adding just a little more $ or if you can find a used pair for sale. They are wonderful sounding,very detailed ( even in low volume ) great bass and the horn tweeter , just right and not too horn sounding but extremely detailed especially the voices.Check them out on YouTube, one of Steve Hoffman’s favourite speakers.

Volti 

Volti & JBL good recommendations.  But see if you can have a pair of Klipschhorns auditioned in your home. Spooky 3D soundstage.  

Do not get the Volti... Grainy sounding treble and doesn't have bass extension.

Get the JBL 4367. I second that recommend

You can call JBL to ask if there's a dealer in your city @kjl1065 

JBL 4367 see here.

Mike

I’d second the Volti’s, or maybe Charney’s.  I have Klipsch Cornwall’s, but they may be too cheap for your situation.

Not sure why you want horns with your powerful amp.  In your price range, horns can be difficult.

Jerry

At your price point I'd say check out Volti Rivals and Lucera should be around your price point. Excellent sounding horns and good looking too.