Specific outcomes from the project
Frequency dependent properties
Effect of IACC on width at high frequencies
Previous research has indicated that the IACC of a signal does not affect the perceived width of a signal above a few kHz. However, it was found that the IACC of the signal or the envelope of the signal can affect the perceived width across the whole of the audio range.
It is commonly stated that the relationship between the IACC and the perceived auditory source width of a sound breaks down above approximately a few kHz. For this reason, measurements of the IACC in the frequency range are regularly omitted.
An experiment was undertaken to investigate the relationship between the IACC and the perceived auditory source width of high frequency stimuli. It was found that if a simulation of the breakdown of phase locking in the ear is included in the measurement, there is a strong correlation between the IACC and the perceived width across all frequencies in the audio range. Therefore a large majority of the audio bandwidth is included in the measurement model. It must be noted, however, that it is not necessarily the case that the whole frequency range has equal perceptual importance - this needs to be investigated in future.
[Mason et al 2005a