Investigation into and modelling of head movement for objective evaluation of the spatial impression of audio.

Abstract

Research was undertaken to determine the nature of head movements made when judging spatial impression and to incorporate these into a system for measuring, in a perceptually relevant manner, the acoustic parameters which contribute to spatial impression: interaural time and level differences and interaural cross-correlation coefficient. First, a subjective test was conducted that showed that (i) the amount of head movement was larger when evaluating source width and envelopment than when judging localization and timbre and (ii) the pattern of head movement resulted in ear positions that formed a sloped area. These findings led to the design of a binaural signal capture technique using a sphere with multiple microphones, mounted on a simulated torso. Evaluation of this technique revealed that it would be appropriate for the prediction of perceived spatial attributes including both source direction and aspects of spatial impression. Reliable derivation of these attributes across the range of ear positions determined from the earlier subjective test was shown to be possible with a limited number of microphones through an appropriate interpolation and calculation technique. A prototype capture system was suggested as a result, using a sphere with torso, with 21 omnidirectional microphones on each side. [Work supported by the Engineering and Physical Sciences Research Council (EPSRC), UK, Grant No. EP/D049253.]

Taking Head Movements Into Account in Measurement of Spacial Attributes

“…However, this information is essential in order to determine the range and pattern of head positions that should be taken into account when capturing suitable binaural signals for analysis. An experiment that examined this is briefly described, and readers are referred to the original publications 11,12 for further information.…”

“…To investigate the difference in the performances of these two models in more detail, the authors designed another set of experiments where the physical parameters related to spatial impression were measured and compared. The results are summarised below, and more information can be found in the original publications 13,12 .…”

Perceptual Matching of Room Acoustics for Auditory Augmented Reality in Small Rooms - Literature Review and Theoretical Framework

“…It is known that head motion facilitates sound source localization and improves localization accuracy (Thurlow et al, 1967; Mackensen, 2004; Honda et al, 2013) and helps to resolve front-back ambiguities (Pöntynen & Salminen, 2019). Kim et al (2013) observed that listeners move their heads over a wider range when judging source width and listener envelopment than for sound source localization. For the evaluation of timbre, the range of head rotation in azimuth was very low compared to the other tasks.…”

Insights into dynamic sound localisation: A direction-dependent comparison between human listeners and a Bayesian model

“…The current experiments focus on small head rotations (10 • ) along the yaw axis. Small head movements have been shown to comprise the majority of natural head movements [17], and can be considered, if necessary, as a first step in a more complex movement framework. An added benefit of small rotation angles is that they allow us to approximate the rotation with a single axis and a constant acceleration.…”