Using Matching Pursuit for Estimating Mixing Time Within Room Impulse Responses

In Room Acoustics, the quantity that fully describes the hall is a set of room impulse responses (RIRs), which are composed of the succession of arrivals (i.e., some sound rays which have undergone one or more reflections on their way from the source to the receiver). The mixing time is defined as the time it takes for initially adjacent sound rays to spread uniformly across the room. This paper proposes to investigate the temporal distribution of arrivals and the estimation of mixing time. A method based on maxima of correlations (Matching Pursuit) between the source impulse and the RIR allows to estimate in practice arrivals. This paper compares the cumulative distribution function of arrivals of experimental and synthesized RIRs (using a stochastic model). The mixing time is estimated when the arrival density becomes constant. The dependence of mixing time upon the distance source/receiver is investigated with measured and synthesized RIRs.