Horn speakers for vintage sound

Altec A5 is what you need. 3 way Hiraga crossovers with a super tweeter. Altec 1505, 288 mid drivers and 1505 horns.  I use 7.5 watts tube power and you can’t be in the same room at 50% volume. I augment with horn loaded subs. You could probably be all in for 5K if you shop around.   Super tweeters are Faital pro HF10AK on custom horns and Lpads since they are 110db efficient. It’s extremely live sounding.  Pete Riggle builds Hiraga inspired crossovers for a 3 way system that are hard to beat. If your ever near Dallas, stop by.  It’s worth hearing. 

I have a pair of JBL 590 for Saale in okay condition for cheap.  But no shipping. 

I have a pair of vintage University "Dean" horn-loaded speakers from the 1960s. PM if interested. There is a massive 15-inch driver in the "doghouse" that makes wonderful bass. Efficiency is off the chart at 104 db at 1 meter at 1 watt, PM if interested.

While you may be able to find some vintage horns, newer designs sound better (not to disparage the older stuff), and in some cases are price competitive with the older vintage speakers.  Check out the custom horn speakers made by John Kalinowski.  Excellent sound within your budget: bd-design.nl

While it sounds like you are looking at traditional horn-based high efficiency systems (compression midrange and horn, plus other drivers for bass and tweeter), there are other approaches to similar kind of sound (very lively and engaging, particularly at lower volume), that are more budget friendly and great for someone who is handy at building gear.  There are some quite decent full-range or wide-range drivers that can be used in multi-way and even single driver systems.

Until fairly recently, I have never heard single driver conventional dynamic speaker systems that did not have a few shortcoming that were show stoppers for me.  But, I have now heard quite satisfying single driver systems.  Some could be assembled as do it yourself speakers by someone who is good with wood working.  I particularly like some of the 8" and 10" full range drivers in "quarter wave back-loaded horn" systems (look at Charney Audio for commercial system using that approach).  While the tapered horn of the Charney might be hard to do, there are simplified versions that work quite well like the "tapered quarter wave tube" cabinet (also often described as "TQWT").  While some of the better 8" and 10" drivers are not that inexpensive as new drivers (e.g., AER, Voxativ, Cube Audio), there are cheaper alternatives out there (e.g., Tangband) that work quite well.