Horizontal-plane localization is mature while elevation reproduction is newly addressed

Evidence

Vertical localization “blur” (uncertainty) is about 17° for an unfamiliar voice, about 9° for a familiar voice and 4° for white noise (Blauert, 1996). If we have no idea of the spectral content of a specific sound, there is no assurance that we would automatically perceive it at its true elevation. … We rely greatly on “plausibility” when localizing in complex situations. Aircraft are automatically assumed to be above us. Nothing is localized below the floor. Voices are where the lips are on the screen—the ventriloquism effect. If listeners are predisposed to think that sounds are coming from above, that is what they are likely to perceive; hence the emphasis on hovering helicopters and bird sounds in demonstrations of immersive sound systems. — , Toole, Floyd E - Sound reproduction-…, 1762 (#expands, via linked claim)

The purpose of these extra channels is to improve the surround-sound experience for the listener so that they have more consistent localization all the way around themselves. In addition, some arrangements can be used to give an illusion of source height, which can give the listener a more realistic sense of the environment the reproduced sound is in. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2227 (#expands, via linked claim)

Categorization

• XREF: connects to: Sound localization by elevation is guided by plausibility, not just acoustics — , Toole, Floyd E - Sound reproduction-…, 1762; Individualized HRTFs only improve localization in planes requiring pinnae cues; Extra surround channels mainly aim at consistent localization and height illusion — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2227 (+2 more)

Broader Connections

• Individualized HRTFs only improve localization in planes requiring pinnae cues #corroborates (0.80)
• Sound localization by elevation is guided by plausibility, not just acoustics #expands (0.75) — , Toole, Floyd E - Sound reproduction-…, 1762
• Extra surround channels mainly aim at consistent localization and height illusion #expands (0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2227
• Head symmetry creates a cone of directions where sound localization is ambiguous #contradicts (0.70)
• Limited human spatial resolution allows plausible upmix from fewer source channels #expands (0.70)