Equalization in an acoustic reverberant environment: Robustness results

This paper investigates the robustness of sound equalization using a room r esponse inverse filter with respect to changing or uncertain source or micr ophone positions, It is shown that due to the variations of the transfer fu nction from point to point in a room, even small changes in the source or m icrophone position of just a few tenths of the acoustic wavelength can caus e large degradations in the equalized room response. The robustness problem is especially acute at high frequencies, which are known to carry some imp ortant attributes of the speech signal. The spatial extent of equalization, derived from the statistical-average properties of sound transmission in r ooms, is illustrated by computer simulations which corroborate the theoreti cal results presented in the paper.