The Subwoofer Room Impulse Response (SUBRIR) database introduced in this report is a collection of RIRs measured in an empty rectangular domestic listening room using a subwoofer as the sound source. Two subwoofers with different characteristics and two types of omnidirectional microphones were used to measure the RIR at different locations, for a total of 96 measurements. Performing acoustic measurements at very LFs presents some difficulties, mainly related to LF ambient noise and unavoidable nonlinear distortions of the subwoofer. It is shown that these issues can be addressed and partially solved by means of the exponential sine-sweep technique and a careful calibration of the measurement equipment. The purpose of this database is to provide acoustic measurements within the frequency region of modal resonances of such small spaces. A procedure for estimating the reverberation time at very low frequencies is proposed, which uses a cosine-modulated filterbank and an approximation of the RIRs using parametric models in order to reduce problems related to low signal-to-noise ratio and to the length of typical band-pass filter responses. The Exponential Sine-Sweep (ESS) technique has been chosen to estimate the RIRs because of its robustness to nonlinear distortions and its capability of providing a higher SNR at LFs. However, not all distortions can be isolated using the ESS technique, with impulsive distortions and odd-order harmonic distortions partially overlapping with the causal RIR.
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