"Colorless" artificial reverberation
Manfred R. Schroeder, Benjamin F. Logan · IRE Transactions on Audio · 1960
An artificial reverberator is described which has a flat amplitude-frequency response and therefore does not alter the spectral balance or “color” of the reverberated sound. Neither does the reverberator add any extraneous hollow, reedy, or metallic qualities or flutter echoes of its own. The number of echoes per second increases with time according to the same law governing the echo statistics of a real room. Thus, it is compatible with the most exacting fidelity requirements in sound recording, home use, and the electroacoustic conversion of auditoriums and theaters, designed primarily for speech, into concert halls. In the last application, the flat amplitude-frequency response of the reverberator minimizes acoustic feedback problems associated with other artificial reverberation devices.