Constant-directivity horns trade low-frequency reach for high efficiency and sustained output.

Evidence

The constant directivity horn: This is the other main technique. It has a constant directivity above a specific frequency or frequencies and is simple and very efficient. It can convert about 25% of its electrical energy input into acoustic energy and is able to sustain outputs of around 10 W (130 dB) of acoustic power for long periods of time. Its main limitation is its low-frequency performance, which typically limits its frequency range to frequencies that are greater than 500 Hz. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2498

Categorization

• DEFINE: Defines the constant directivity horn and quantifies its ~25% efficiency and 10 W sustained output.