Abstract
Under natural conditions, listeners perceptually attribute sounds to external objects in their environment. This core function of perceptual inference is often distorted when sounds are produced via hearing devices such as headphones or hearing aids, resulting in sources being perceived unrealistically close or even inside the head. Psychoacoustic studies suggest a mixed role of various monaural and interaural cues contributing to the externalization process. We developed a model framework for perceptual externalization able to probe the contribution of cue-specific expectation errors and to contrast dynamic versus static strategies for combining those errors within static listening environments. Effects of reverberation and visual information were not considered. The model was applied to various acoustic distortions as tested under various spatially static conditions in five previous experiments. Most accurate predictions were obtained for the combination of monaural and interaural spectral cues with a fixed relative weighting (approximately 60% of monaural and 40% of interaural). That model version was able to reproduce the externalization rating of the five experiments with an average error of 12% (relative to the full rating scale). Further, our results suggest that auditory externalization in spatially static listening situations underlie a fixed weighting of monaural and interaural spectral cues, rather than a dynamic selection of those auditory cues.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
- Figures showing results were updated to improve legibility. Former Fig. 2 is now divided into Fig. 2 and Fig. 3. - Additional analyses were conducted in order to back up our conclusions with respect to the assumed linear relationship of the various rating scales and to test the model against a theoretically internalized diotic listening condition. - The title was adjusted in order to prevent confusion with a certain formalized statistical method (meta analysis), to encompass both the source and the listener being static, and to provide some overlap with the title of an earlier preprint version. - Many descriptions, explanations, and justifications were added to all parts of the main text.
