Speaker drivers’ directivity at high frequencies causes spectral dips in the reverberant field

Evidence

There is an additional effect on the reverberation field, and that is the directivity of the source of sound in the room. Most hi-fi loudspeakers and musical instruments are omnidirectional at low frequencies but are not necessarily so at higher ones. As the level of the reverberant field is a function of both the average absorption and the directivity of the source, the variation in directivity of real musical sources will also have an effect on the reverberant sound field and hence the perception of the timbre of the sound. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1796 (#expands, via linked claim)

Categorization

• XREF: connects to: Directivity mismatch at crossover frequency causes predictable dips in sound power; The stereo phantom center image suffers an audible 2kHz timbre dip affecting speech intelligibility — , Toole, Floyd E - Sound reproduction-…, 673; Increasing speaker directivity reduces the reverberant field like a tone control does (+4 more)

Broader Connections

• A source’s changing directionality with frequency alters perceived timbre via the reverberant field #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1796
• Increasing speaker directivity reduces the reverberant field like a tone control does #expands (0.80)
• Larger speaker size relative to wavelength enables higher directivity #complicates (0.75)