Specific outcomes from the project
Controlled experiment stimuli
Stimuli with tightly controlled parameters are required for research into auditory perception; suitable novel stimuli have been created and used successfully in a series of experiments.
In order to investigate the effect of stimulus centre frequency on the perceived auditory source width, specific stimuli were needed with the following properties: 1) narrow bandwidth - within a single critical band; 2) perceptually constant IACC; 3) easily variable centre frequency; 4) easily variable IACC with no other perceivable changes. A suitable stimulus was derived based on suppressed-carrier amplitude modulation. A number of experiments were conducted to verify the properties of the stimuli created using this technique, and it was found that they met all of the criteria, apart from there was a small trade-off to be made between the perceptually constant IACC and the stimulus bandwidth. In addition, this stimulus could be created with the signal envelope having a range of cross-correlation values, which could be useful for investigating the breakdown of phase locking in the ear.
[Mason et al 2003