Parting from an exposition of the mathematical-physical background for the occurrence of comb-filter distortions, the relations between level proportions, periodicity and delay times in signal sequences are explained with respect to this phenomenon. Derived from this are spectator areas in simple sound-reinforcement constellations where the comb-filter effect disturbs only little or not at all. Diagrams showing the probable audibility of comb-filter distortions are given. All these investigation results are backed up by subjective tests showing the level sequences and ratios at which disturbing comb-filter distortions are no longer perceptible. Finally an attempt is made to give recommendations as to how this disturbing effect can be avoided beforehand in sound reinforcement installations using slightly delayed signal pressure, as e.g. Delta Stereophony Systems.
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