Specific outcomes from the project

Frequency dependent properties

Simulation of breakdown of phase-locking required in measurement model


The necessity of a simulation of the breakdown of phase-locking in a model of perceived width has been established, and a suitable rectification and filtering process derived.


A number of models of the human hearing system include a simulation of the breakdown of the phase locking of the inner hair cells at higher frequencies. These range from complex biological simulations to a simple half-wave rectification and low-pass filter process. However, such a process is rarely included in IACC-based measurements.

An experiment was conducted to investigate the importance of a simulation of the breakdown of phase locking in IACC-based measurements, and to derive a suitable yet practical method of simulation. It was found that it was important to simulate the breakdown of phase locking for signals with a frequency of greater than approximately 1000 Hz, as above this the perception of width is dependent on the correlation of the envelope of the signal, rather than the correlation of the fine temporal detail. A suitable method of simulating this in the measurement was found by combining half-wave rectification with a simple filter.


[Mason et al 2005a]