Speakers for a Large Room (20’x37’)

One other option, sort of off the beaten path is the Classic Audio Reproductions line.

We've done ballrooms with the Classic Audio Loudspeakers T-1 and T-3. With that room size using those speakers I'd recommend 100 watts if you plan to crank it up. That would be true of any of the Tannoys as well. If you have a Klipsh corner horn set you might get by with 20-30 watts. That's a big room- you don't want to push the amp hard if you want the best sound- it makes a difference!

I would agree with the Nola KO for a large room. I have to say I heard the new model, The Champ. Nola was in a large room at The Capital Audiofest. The Champs carried the room with no problem.

Who is the Nola dealer in the U.S.?   These look interesting.

@doni 

Call Carl or Marilyn at Nola and they will direct you to a dealer.  They are located in Brooklyn.  The KO is a great speaker. I have owned a pair for almost six years.  The price has climbed steadily over the years though.  The Champ is the same concept just smaller cabinet and fewer drivers.  

Several have already mentioned the Klipsch Cornwall...I concur as well, however if you really want to pressurize a space as large as yours I can suggest stacked Klipsch Cornwall’s. I have such a set up and they are spectacular. You invert the top pair so that you have a “D’Appolito”  alignment. (MTM...Midrange, Tweeter, Midrange). The only downside is some “ Comb Filtering” effects, however it’s not to bad. The stacked Cornwall’s are shockingly dynamic, and image surprisingly well, considering the Comb Filtering that takes place, especially if you can set them up so that they are well out into the room, and your seating distance is at least that of a equilateral triangle ( even a little farther back will help with imaging  (the Comb Filtering effects won’t be as noticeable.)

Cheers....