Headphone simulation of free-field listening. II: Psychophysical validation

TLDR

The study aimed to duplicate free‑field waveforms at the listener’s eardrums by digitally processing headphone stimuli. Using subject‑specific free‑field‑to‑eardrum transfer functions measured at 144 locations, the authors processed headphone stimuli and had eight listeners report spatial positions of wideband noise bursts, which matched free‑field positions. Headphone‑processed stimuli produced localization similar to free field but with more front‑back confusions and slightly poorer elevation definition, and one subject’s elevation errors were linked to distorted transfer‑function features.

Abstract

Listeners reported the apparent spatial positions of wideband noise bursts that were presented either by loudspeakers in free field or by headphones. The headphone stimuli were digitally processed with the aim of duplicating, at a listener's eardrums, the waveforms that were produced by the free-field stimuli. The processing algorithms were based on each subject's free-field-to-eardrum transfer functions that had been measured at 144 free-field source locations. The headphone stimuli were localized by eight subjects in virtually the same positions as the corresponding free-field stimuli. However, with headphone stimuli, there were more front-back confusions, and source elevation seemed slightly less well defined. One subject's difficulty with elevation judgments, which was observed both with free-field and with headphone stimuli, was traced to distorted features of the free-field-to-eardrum transfer function.