ABSTRACT
The acoustic analysis of architectural spaces has been widely studied in recent years and has taken different approaches, including simulation.
In large music halls and particular those with heritage value, it of great interest to know, in addition to current acoustic conditions, what the situation would be after future interventions caused by a change in use. A reliable model is needed to forecast the variation in these conditions, as any intervention to improve acoustics is always costly, both in terms of budget and alteration to the interior architecture.
Thus it is particularly important to be able to simulate the effect of any change in the geometric characteristics of the room or the materials used.
In general, acoustic simulation software (Odeon, Caat, etc.) works on a three-dimensional model of the music hall and applies absorption coefficient values to the cladding materials taken from the literature or directly from tests when the case allows. This simulation provides the time and energy quality parameter values, the most important being reverberation time in relation to frequency (for each octave or third of an octave)
In addition, these parameters are measured “in situ” and their values usually differ from the simulated values. The simulation results are then adjusted to the measured results until they coincide to a certain degree.
Currently this adjustment is made using an iterative method, generally based on the experience of the operator who introduces reasonable variations for the absorption coefficient values until a sufficient or acceptable approximation is achieved between the simulated tone curve and the measured tone curve.
The aim of this present study is to apply the mathematical Response Surface Method to the phase of adjusting absorption coefficients for the construction materials or solutions used to clad an architectural space.
This method contributes a protocol for the absorption coefficient adjustment stage in the process of simulating music hall acoustics. This systematised protocol for the phase avoids the arbitrariness of the iterative method, both in assigning values for these coefficients and their respective deviations. In addition, it has been found that when applying this method to premises with different volumes or geometry, as a closed protocol is followed, there is no variation in the accuracy of the results.