Differential contribution of interaural time and level differences to the precedence effect at high frequencies

The precedence effect (PE) allows us to locate sound sources correctly in rooms despite the presence of interfering reflections. It was shown to function at high frequencies with highly modulated stimuli even when lead and lag had simultaneous onsets, i.e. with information restricted to the ongoing sound part [1]. These studies were done in the free-field where interaural time (ITDs) and level (ILDs) differences are in their natural combination. The present study investigated the relative contribution of ILDs and ITDs to the PE and if either cue alone is sufficient to evoke the PE. Zero-phase harmonic complex tones restricted to high-frequencies were used. At high frequencies only ILDs and ITDs carried in the envelope are used by the binaural system and it is questionable if they can be accessed in the presence of a sound reflection.