Directivity mismatch at crossover frequency causes predictable dips in sound power
Evidence
When one looks at the far off-axis performance, as displayed in the early reflections and sound power curves, there are large fluctuations that affect the sound of the reflected sound field. The directivity index shows the rising directionality of the twin woofers, crossing over to the large 6-inch (150 mm) midrange driver around 400 Hz that, in turn, becomes increasingly directional until it crosses over to the unbaffled 1-inch (25 mm) tweeter around 4 kHz. The broad dip in sound power and the rise in directivity around 3 kHz are predictable results of the mismatch in directivity in the midrange-to-tweeter crossover region. — Toole, Floyd E, Sound reproduction- the acoustics and…, 241
Categorization
Category: Causal Relationships
- DEFINE: Explains directivity index and how crossover directivity mismatch produces measurable dips.
Related
- Speaker drivers’ directivity at high frequencies causes spectral dips in the reverberant field (similarity 0.86)
- Speaker and instrument directivity at high frequencies alters perceived timbre (similarity 0.84)
- Microphones become more directional at higher frequencies, darkening off-axis reverberant sound (similarity 0.82)
- Increasing speaker directivity reduces the reverberant field like a tone control does (similarity 0.81)
- Microphone directivity in impulse response recording controls perceived reverberation amount (similarity 0.81)
- Popular recording microphones vary significantly in high-frequency and directivity performance (similarity 0.79)
- Large path-length variation causes poor direct-to-reverberant ratio and feedback (similarity 0.79)
- Smaller drivers radiate more omnidirectionally at a wider frequency range (similarity 0.79)
- A speaker’s coverage angle roughly doubles for each octave below its minimum directivity frequency. (similarity 0.79)
- A source’s changing directionality with frequency alters perceived timbre via the reverberant field (similarity 0.79)
- Microphone performance variation rivals or exceeds loudspeaker variation (similarity 0.79)
- Microphone construction determines directional sensitivity patterns like cardioid and dipole (similarity 0.79)
- Directivity, not equalizable response, is the fixed determinant of loudspeaker sound. (similarity 0.78)
- The optimum direct-to-reflected sound ratio rises from speech to music (similarity 0.78)
- As wavelength shrinks below diaphragm size, speakers beam and off-axis sound diverges spectrally (similarity 0.78)
Broader Connections
- Speaker drivers’ directivity at high frequencies causes spectral dips in the reverberant field
#corroborates(0.92) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1846 - Increasing speaker directivity reduces the reverberant field like a tone control does
#expands(0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1845