Dependence of accuracy of reverberation time measurement on input filters
Dragana S. Sumarac · The Journal of the Acoustical Society of America · 1998
In this paper, attention was paid to the standard method for measuring frequency characteristics of reverberation time in rooms. The influence of transfer function characteristics of 1/1 and 1/3 digital octave input filters on differences in measuring values of reverberation time was studied. Procedures for complete digital analysis of recorded impulse response of the room were designed. All procedures were designed by the matlab software package. The verification of that measuring software was performed on a great number of recorded impulses in real rooms. The several classes of 1/1 and 1/3 digital octave FIR and IIR filters were designed according to the international standard IEC 225. The complete analysis was performed using the recorded reverberation decay curve in 20 rooms significantly different in volume and reverberation time values. The rooms were excited with broadband pink noise and short duration impulses. The values of measured reverberation times were statistically analyzed to show the expected variance that can appear due to differences of applied 1/1 and 1/3 digital input filters.