Filtering and removal of the effects of the transducers on the acoustical impulse response of concert halls

Abstract

Digital signal processing (DSP) has enabled the exponential sine sweep (ESS) method of measuring the acoustical parameters of a concert hall to be increasingly efficient. Part of this is due to the implementation of software modules that perform specific tasks such as filtering and equalization. In using a measurement loudspeaker source for the sine sweep process, it is necessary to: first, derive a loudspeaker prefilter to ensure that the resulting output sweep possesses a frequency response that is reasonably uniform; and second, to derive a transducer inverse filter in order to remove the effects of the loudspeakers and microphones from the measured impulse response of the hall. In the present work, by measuring the acoustical impulse response function (AIRF) of three different halls, using a high-frequency (HF) horn-loaded loudspeaker system as a reference source, it is shown that the effects of the transducers may be effectively filtered and removed from the AIRF.