a Ray Tracing Computative Method for Architectural Spaces Incorporating Interference Phenomena.

The sound pressure level (SPL) can be modelled at various locations within an enclosed acoustical space by using ray tracing techniques. Ray tracing techniques are used to approximate the wave behavior produced by sources within the space. The analysis is usually accomplished by summing all the energy gathered by a receiver and then comparing this sum to the energy sent from the source, and disregarding the phase of the associated wave. From this standpoint ray tracing must assume that the rays received will have randomly distributed energies, phases and directions (Sabine's assumption of uniform energy density). In dealing with non-Sabine cases, such as a small room or close to the source of a nondiffuse room, the assumption of randomness is no longer valid. In these situations for a source output consisting of a monotone or containing strong monotone components summing of the total ray energy at the receiver may yield large discrepancies due to interference effects caused by the phase of each wave, as well as, phase changes at walls due to impedance. In this investigation, these phase changes, which lead to interference effects, are incorporated into the ray tracing method for the first time. The live end-dead end, the studio control room, and a comparison of the method with measured results are important findings of this work.