SPEAKER SYSTEMS FOR VOCAL HEAVY APPLICATIONS.
Cards on the table. I have a major beef with most loudspeaker manufacturers. Most actually know better. The major brands certainly do! But for some reason the average system installed in most school theatres is either a 2 way 12" and horn or a 15" and horn system.
BAD. VERY BAD!
the fundamental frequency of most voices is much smaller than the diameter of the 12"/15" woofer that in most cases is expected to handle up to 1200-1500-2000Hz. In order for the cone to reproduce the voice it has to distort the cone - yes distort. This means it sounds less than natural Now to some extend almost all frequencies have to distort the come or diaphragm in order to produce those notes, but the smaller the speaker the more natural the sound of the voice tends to be.
And then there is the horn. I hate horns. They exist to help overcome the difficulty in propagating high frequencies over long distances. Again they introduce all sorts of distortion into a system and in my opinion should never be used below 3,000 Hz (the higher the better). If you cross them over in the vocal band (300-3,000Hz) you have 2 very different sounding devices trying to reproduce the voice, and at the crossover region you will get some very strange behaviors.
My preferred option is a good three-way system - woofer (40-180/200Hz - 10-15"), vocal range (180-3,000 3-6") and highs (3,000-18,000 - cone, ribbon, dome or horn). There are not a lot of mid market product that met these specs - my default is a 10"/horn crossed at 2,000-2500Hz as a compromise. Most newer concert line array systems are based on my philosophy using 4", 5" or 6" cone speakers (sometimes horn loaded) to handle most of the vocal band.
Moral - never use a 12 and horn or 15 and horn for vocal reinforcement unless you have absolutely no alternative. If budget is a concern use an 8" or 10" 2 way and a subwoofer on the floor. If you can afford a line array system then something like our Studiomaster V5 system is perfect for theatres - again I would normally fly the top boxes (V5) and floor mount the powered sub-woofer - in a big room you may fly some subs and floor mount the rest. The issue is that frequencies below 120 Hz are omnidirectional so it doesn't matter were the are positioned (except for time alignment - more on that in another post), but between 120 and the top box there is some directionality, so it is best that some of that information is coming from the same place as the information abouve 180Hz.