Even though convolution reverbs are arguably the best sounding and most convincing reverbs out there today, algorithmic reverbs remain highly useful in the audio designer’s toolbox. Some of the earliest reverb designs proposed and implemented were done by Schroeder and Moorer in the early 1960′s and late 1970′s respectively. Here I examine the details of Moorer’s analog design in translating it into the digital domain (an earlier look Schroeder’s version can be seen here).
One of these was the use of a tapped delay line to simulate early reflections, which are of crucial importance in the perception of acoustic space, moreso than the late reflections. This tapped delay line that forms the basis of the early reflections can contain delay times and a gain structure that could be modelled on a measured acoustic space, like a concert hall for instance. In fact, Moorer did just that, and in his article “About This Reverberation Business” in the Computer Music Journal, he offers up a 19-tap delay line that was taken from a geometric simulation of the Boston Symphony Hall.