An improved reverberation processor includes a technique for changing environmental parameters without causing disturbing audio artifacts. The technique includes the steps of sequentially changing the read pointers of different delay lines. Additionally, for each delay line a level control variable is ramped down prior to changing the read pointer and then ramped back up. The reverberation processor also provides means for producing and controlling a repeating echo in the reverberation decay, as well as adjusting the diffusion (or echo density) of the reverberation.