On The Stick
When portable loudspeakers serve as mains, typically they’re deployed to either side of the stage on stands.
This provides good overall coverage and also positions the loudspeakers toward the “dead” rear of the cardioid pattern of microphones, reducing the potential for feedback.
Also, they should be high enough to clear the crowd; otherwise, people in the back will hear muffled sound because the crowd attenuates the high frequencies.
Raising the loudspeakers also prevents sound from blasting the front rows of the audience.
Articulation is best if the direct-sound level is high relative to the reflected-sound level.
This is achieved by locating the loudspeakers close to the audience and aiming them to direct their sound on the audience, not on reflecting surfaces.
While placement is often done on an “eyeball” basis, sometimes a bit more preparation can make a big difference.
Using graph paper or a computer, make a scale drawing of the venue. Inside this venue, draw the loudspeakers and their sound radiation angle, both in a top view and a side view.
Experiment with angling and placement so that the maximum amount sound is directed to the sound absorbing audience.
At left, positioning loudspeakers in a central location and splaying them can help prevent phase interference and comb filtering. At right, a look at the A/B Technique.
In some scenarios, when loudspeakers are placed on either side of the stage, audience members seated near the front row can be located too far from those loudspeakers, as well as too far off-axis.
This problem is usually overcome by adding a fill loudspeaker (or a few) near the front edge of the stage in the center.
An alternative approach is to position two loudspeakers in a central location, then stack and splay them.
This helps prevent the phase interference and comb filtering that can occur with spaced loudspeakers.
Hanging & Mounting
In a theater used for drama or musicals, there might be the need to place the loudspeakers closer to the audience than a typical over-the-stage location.
Options include hanging the loudspeakers over the audience (high enough to not block the view of the stage); mounting the loudspeakers on portable stands; and mounting the loudspeakers on the side walls (if enough coverage can be delivered to the center of the audience).
Keep in mind that the flying of loudspeakers must be done by a licensed professional rigger who follows safety standards.