A common application of both fixed and portable sound reinforcement systems is for meetings spaces of 50 people or less seated on a flat floor plane.
Here are some approaches that have produced good results.
One of the important principles to follow in such spaces is to aim the loudspeaker at the back row. Those folks need the highest SPL and directivity, both of which are usually on the main axis of the loudspeaker.
It’s also important to not overpower the front rows when projecting sound to the back rows. This mandates a tight vertical coverage pattern – one that can miss the front when aimed at the back.
Elevating the loudspeaker helps tremendously in achieving even coverage, but meeting rooms generally have ceiling height restrictions that limit how high the loudspeaker can go.
Since so many of our seminars are held in rooms that are approximately 50 ft x 50 ft x 12 ft, I modeled the room and tried a few loudspeaker balloons for coverage.
Above-Behind-Tilt placement of an active and passive line array. (click to enlarge)
It is immediately apparent that a low loudspeaker placement requires vertical pattern control. The small-format line array (or sound column) is well-suited for this task.
The horizontal pattern is typically broad due to the use of small transducers in the array. The vertical pattern is narrowed at high frequencies due to the phase relationships of the vertically-stacked drivers.
This “Frisbee-shaped” pattern allows sound energy to be concentrated on the farthest listeners, and fall off in the front of the room where the listeners are closer to the loudspeaker (and talker).