Reference : Numerical evidence of mixing in rooms using the free path temporal distribution
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Numerical evidence of mixing in rooms using the free path temporal distribution
[fr] Mise en évidence numérique du mélange des ondes sonores dans les salles à l'aide de la distribution temporelle du libre parcours
Billon, Alexis [Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Electroacoustique, acoustique appliquée et éclairage >]
Embrechts, Jean-Jacques mailto [Université de Liège - ULiège > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Techniques du son et de l'image >]
Journal of the Acoustical Society of America
American Institute of Physics
Yes (verified by ORBi)
[en] Room acoustics ; Mixing ; Ray-tracing
[en] The ergodic propriety of a room has strong effects on its reverberation. If the room is ergodic, the reverberation can be broken up in two steps: a deterministic process followed by a stochastic one. The late reverberation can be then modeled by a reverberation algorithm instead of more computationally consuming methods. In this study, the free path temporal distribution obtained by ray-tracing is used as an indicator of the room’s mixing: the energetic average of the path lengths is computed at each time step. Ergodic rooms are thus characterized by rapidly convergent distributions. The free path value becomes independent of time. On the other hand, path selection mechanism and orbits are observed in non-ergodic rooms. The transition time from the deterministic process to the stochastic one is also studied through the evaluation of the room’s time constant. It is shown that its value depends only on the mean free path and the boundaries scattering value. An empirical expression is obtained which agrees well with simulations carried out in a concert hall. This transition time from a deterministic model to a stochastic one can be used to speed up the acoustical predictions and auralizations in ergodic rooms.
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS

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