Specific outcomes from the project

Temporal properties

Temporal resolution of IACC perception


Rapid increases in the perceived width of a sound (i.e. decreases in the IACC) can be perceived more easily than rapid decreases in the width of the sound (i.e. increases in the IACC). This has been implemented in the model as a dynamically varying temporal filter.


A number of studies have been undertaken previously that investigate the temporal resolution of variations in the IACC, though most of these have focused on the effect on binaural masking rather than perception of auditory source width. A number of experiments were conducted to investigate this in more detail in order to accurately predict the perceived width of stimuli whose characteristics change over time.

The first experiment investigated the perceived maximum and minimum widths of stimuli whose IACC was changing between 0 and 1 at various rates. The second experiment extended this to include stimuli whose IACC was changing between other values. The final experiment applied the results of the earlier experiments to noise-based stimuli whose IACC was varied in one short period from 1 to a lower value with a range of differing periods of variation. The results indicated that increases in width (or decreases in correlation) are perceived more rapidly than decreases in width (or increases in correlation). A method to simulate this using a complex direction-dependent filter was derived for inclusion in the measurement model.


[Mason et al 2003]