Ideal public address speakers radiate a frequency-constant angle of sound energy

Evidence

Ideally, speakers for public address systems should have a direc­ tivity that is constant with frequency; that is, the angles into which they radiate their sound energy remain the same over the whole audio spectrum. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2483

Categorization

• DEFINE: Defines ‘constant directivity’ precisely as unchanged radiation angle across the audio spectrum — a term that recurs throughout the chapter.
• SEED: Angle: why almost no real loudspeaker achieves constant directivity, and what that failure does to a listener’s perception of tone.