A technique is presented for estimating finite‐amplitude effects for standing acoustic waves. The method consists of equating the nonlinear energy loss from the fundamental mode of oscillation to the work done on this mode by its higher harmonics. The higher harmonics are determined by the assumption that the wave‐form is a sawtooth. Results are obtained for the limiting amplitude of oscillation, which are in qualitative agreement with previous results where these are available. The problems considered are (1) propagation of simple waves; (2) sound produced by a piston in a closed tube; (3) sound resulting from acoustic instability in a closed tube; (4) sound produced by a piston in a closed tube with the even harmonics strongly damped; and (5) sound resulting from acoustic instability in a closed tube with the even harmonics strongly damped.