The normalized variance due to the finite integration time of instrumentation used for determining the space‐time average of the sound‐pressure level in a reverberant room is given by 19/BTI, in (dB)2, whereBis the bandwidth of noise andTIthe integration time of instrumentation. This result is smaller by a factor of 2 than an earlier result reported by Andres [Acustica16, 271–294 (1965). Transl.: Bolt, Beranek and Newman, TIR‐10 (1968)]. This factor may account for the difference between the result found by Andres and the results reported by Kurtovic [Ann. Telecommun.16, 254–261 (1961)], Schroeder [J. Acoust. Soc. Amer.46, 277–283 (1969)], and Lubman [J. Acoust. Soc. Amer.44, 1491–1502 (1968)] for the normalized variance of the sound‐pressure level.