The demands concerning the quality of sound reinforcement at live concerts have increased constantly over the past years. A linear transfer characteristic for all audience areas, rich and pounding bass transmission, and considerable levels free from distortion are expected by the listener just as well as by the involved technicians. Rising levels have also increased the risk of feedbacks, which can be reduced by a directional and focused coverage of the audience areas and by excluding the stage from the target area.
Beside traditional loudspeaker clusters, powerful line arrays have made their way on stage, and make possible an even coverage of wide listener areas. Recently a directional bass reinforcement, implemented with cardioid configurations or other bass arrays, is getting increasingly popular. The effort for planning these loudspeaker arrangements is higher than for conventional arrays, and even intensified by delay lines and specific solutions for boundary areas or side rooms.