Constant-directivity horns are efficient but cannot cover frequencies below 500 Hz
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
Category: Factual Claims
Related
- Horn size physically constrains the frequency range of directional coverage (similarity 0.86)
- Horn coverage angle doubles for every octave below the minimum directivity frequency. (similarity 0.84)
- Horn confinement amplifies siren output via proximity resonance. (similarity 0.80)
- A horn amplifies sound without increasing diaphragm motion (similarity 0.80)
- Horn loudspeakers amplify sound through proximity resonance in a narrow throat (similarity 0.80)
- Horn throats boost output by constructive interference with the source (similarity 0.79)
- Concentrating sound into a smaller solid angle raises horn sensitivity (similarity 0.79)
- A horn’s main benefit is source loading, not directional aiming. (similarity 0.79)
- Small horn mouths fail to provide advertised directivity at speech frequencies (similarity 0.79)
- The conical horn converts a closed-reed tube into a full harmonic instrument (similarity 0.78)
Broader Connections
- Concentrating sound into a smaller solid angle raises horn sensitivity
#expands(0.75) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2519 - Horn bells boost lower frequencies where wall friction dominates resonance enhancement
#qualifies(0.75) — Eric J. Heller, Why You Hear What You Hear- An…, 1708 - Coherent summation of aligned horns lets off-axis points act on-axis
#corroborates(0.72) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2533 - Directivity mismatch at crossover frequency causes predictable dips in sound power
#expands(0.72) — Toole, Floyd E, Sound reproduction- the acoustics and…, 241