Predicted and experimental results of acoustic parameters in the new Symphony Hall in Pamplona, Spain

Two room acoustical simulation software have been used to predict the main acoustic parameters of a Symphony Hall in the planning stage, when only drawings were available. The modelled room is the Symphony Hall of the Conference Hall of Navarre, in Pamplona, Spain. Although the values of the calculation parameters (number of rays, reflection order, etc.) recommended by each software are slightly different, in this work the same values were used for both programs. Once the Hall was built, experimental results were obtained using the MLS-measurement technique. The values predicted and measured for several parameters defined in ISO 3382 at 9 receiver positions are compared. Even though the values predicted by both software are very similar for most of the acoustic parameters, there are notable differences at particular values, mainly when evaluating energy ratios. Different statistical corrections for late reflections between both programs seem to be the main reason for these differences. A more exhaustive knowledge of scattering coefficients is required to improve predictive accuracy. Important differences at 250 Hz frequency band were found between calculated and measured values probably due to the yet to be implemented seat dip effect in room simulation software. The comparison of calculated and measured impulse responses seems to be the first choice for the assessment of room simulation software. However, it should be kept in mind that its usability is also determined by many additional features. This work is not only a comparison of software dealing with the same object as well as equal input data but also shows the power of this kind of tool to predict the acoustic parameters of a room before its construction.