Specific outcomes from the project

Signal properties

Effect of lateral position within an auditorium on IACC-based measurements


Previous research has argued that the IACC is not a good predictor of the perceived auditory source width as it can vary a large amount as the received is moved laterally around the centre of an auditorium, whereas musical signals do not vary a large amount in width in these positions. This is due to the fact that previous measurements were made of impulse responses rather than the musical signals that were auditioned. When the IACC-based measurements are made of the musical signals themselves, the predictions match the perceived effect much more closely.


de Vries and colleagues found that IACC-based measurements can vary a large amount across an auditorium, especially around the centre (equidistant from the side walls). They explained that this did not match their informal experience of listening to musical signals in the halls that were measured. Based on this finding they rejected the IACC as unsuitable. However, it is likely that this discrepancy between the measured and perceived effects is due to the fact that they measured wide-band transient impulsive signals, and listened to more continuous and tonal musical signals.

An experiment was conducted to investigate this factor. It was found that the source width of some of the musical signals varied as the lateral position of the receiver was moved - though this was not consistent for all the musical signals. The fact that the results varied for the different signals indicates that measurements of the impulse response will not accurately match the perceived effect for the different musical signals. It was found that this was the case, and that IACC-based measurements made of the musical signals themselves matched the subjective results much more closely.


[To be reported]