A source’s changing directionality with frequency alters perceived timbre via 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

Categorization

• XREF: Links to the reader’s chapter 103 structure on room absorption, adding the source’s directivity (Q) as a second variable. — connects to: Reverberation multiplies perceived speech loudness well beyond measured level gains — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2058; Wood’s anisotropy makes sound radiation direction- and frequency-dependent; Violin timbre changes with direction as high frequencies become increasingly directional — Eric J. Heller, Why You Hear What You Hear- An…, 1785 (+10 more)
• corroborated: 3 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1796

Broader Connections

• Room reverberation time varies with frequency, altering perceived timbre #corroborates (0.92) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1876
• Increasing speaker directivity reduces the reverberant field like a tone control does #qualifies (0.78)
• Equalizer adjustments at specific frequencies produce predictable perceptual shifts in timbre #expands (0.75)