Specific outcomes from the project
Display and interpretation factors
Effect of IACC on ITD and vice versa
The interaction between the interaural time difference (ITD) and the interaural cross-correlation coefficient (IACC) was investigated. It was found that the ITD does not affect the perceived auditory source width unless double peaks occur as discussed below, and that decreasing the IACC causes the sound to move towards the median plane. Methods were derived to model this.
The interaction between the interaural time difference (ITD) and interaural cross-correlation coefficient of sounds has not been considered previously. An experiment was conducted to determine whether these two factors are independent, and whether there is any variation in the perceived auditory source width caused by the ITD or any variation in the perceived location caused by the IACC.
It was found that the IACC can affect the perceived location of a sound. As the IACC is decreased in a sound with a relatively large ITD, the sound is perceived to move towards the centre of the head (the median plane). This possibly occurs because the decreasing decorrelation causes the timing cues to become less clear. On the other hand, the ITD was not found to affect the perceived width of the stimuli, unless double peaks appeared in the cross-correlation plot. This is discussed in more detail below. A method was derived to take the effect of the IACC on the perceived location into account in the binaural hearing model.
Further work is required to determine the relationship between the interaural level difference (ILD) and the IACC of sounds.
[Mason et al 2004c