What do I expect in a horn speaker system?

I never hear about horn speaker, and it is almost impossible to get a choice to hear it when you live in small town in Canada. I may plan to get a Oris horn system, what kind of amp do I need? What is the price range of a horn system?
Price range $1,000 to $250,000 US

A relatively low powered amp will do. How low depends on the efficiency of the speaker but 3 watts or more will usually suffice.

What to expect? Not perfection but if properly set up and fed with the right electronics (big ifs and easy to get wrong) they provide a realism that other speakers can only hint at.
Also: controlled dispersion, very "dynamic" sound (or "aggressive" in bad set-up), very high dynamic range (horns are very sensitive), large size !!, hi level of details is easily perceptible in mid-upper mid range, very hi spl are attainable.

Choose the right driver to put in your horn.

Suggestion:With the New Fertin 20Ex in a horn set up

will give you alivelyness- speed (very dynamic sound)-

lot of details and accuracy that will be remarkable.

Also bass will be quite good (35hz) and no tweeter

neede or crossover. Horn + set + wine= nice evening.
Several years ago I had a set of Klipsch LaScala's driven by an older McIntosh SS amp. Midrange and highs were very good on good recordings. If your musical tastes run to strings, small quartets etc., you will be happy. But for me they did not work out. Hardly any bass unless played very loud and for me most of the bottom end of most recordings were just not there. Newer equipment might be better. YMMV.
listen to several horn designs at length before taking this plunge. i have owned klipsch, odeon, and listened extensively to everything from avante garde, lowther and fostex based custom designs, and more, and they all have their charms...but always returned to drivers in boxes, not so much because of the sounds that were there, but because of the sounds that were not there.
Resonance and resonant peaks are often an issue with horns but they have advantages.

Since solid state electronics provided high amounts of clean power horns went out of fashion with consumers.

Recently they have had come back, possibly driven by a desire to use low power tubes.

Horns never went out of fashion in professional applications such as sound reinforcement - so just head to a local music shop.

Stacks of cheap but effective "bass bins" are used at concerts to allow concert goers to feel the bass.

Of course, sound reinforcment is rarely of audiophile quality and generally requires sound techs to actively manage the system to get the desired sound (often changing settings from track to track).
A proper front horn system will need a med to small power amplifier.Can provide massive dynamic range that conventional designs cant reproduce, have controled dispersion so dont interact as much with your room.Many vintage horns do have a vintage sound they can sure be fun so YMMV but I find them to perform far below modern horn systems. Most of the truly - things I read about horns seem to come from folks who owned, heard vintage or think PA when they think horn. If the horn system is of proper design resonance problems will not be a issue.A problem for front horns systems is driver integration some Avant Gardes systems suffer from this.A good front horn system can be costly but if you buy used sometimes you can find a deal.