Now for something completely different.
Acousticians have known since even before the beginning of speaker design that horn loaded speakers are the most efficient way to amplify audio That's because, unlike most of the cone loaded speakers that we're used to, horns are very directional and don't waste energy pointing sounds in a direction other than where the audience is seated. Who cares if the spider on the ceiling is hearing a playback as well as you are?
While horn-loaded speakers come in and out of style, they're always with us in some form. The latest foray into horned audio territory for the home is the La Grande Castine speakers (pictured left), designed by the French company Musique Concrete (can't find a website for them). Their large size and acoustic shape allow them to deliver sound in the 108dB range with a mere 3 watt amplifier. Now that's efficiency! They'll cost you though - about $100,000 per pair.
Usually you'd find a set of three of these speakers set behind the screen. The bigger the theater, the larger the speaker. In fact, in many large theaters that project Sony's SDDS format films, you'll find an array of five sets, although they'll probably be from JBL since Altec has regrettably left this area of the business some time ago.
Probably the most widely revered and sought after horn-loaded speaker is the oldest - the RCA "Ubangi," which was used in the original theater sound systems until about the 60's and latter utilized as the primary piece of Allen Sides famed studio monitors of the 80's and 90's. Since almost all theaters that used these have either closed or upgraded to newer gear long ago. If you have any pictures of a Ubangi, please send it along.