“In acoustics, comb filtering can arise in some unwanted ways. For instance, when two loudspeakers are playing the same signal at different distances from the listener, there is a comb filtering effect on the signal. In any enclosed space, listeners hear a mixture of direct sound and reflected sound. Because the reflected sound takes a longer path, it constitutes a delayed version of the direct sound and a comb filter is created where the two combine at the listener”
Avoiding or minimizing comb filtering is basically the game in good audio. Aim the speakers where the ears are, not on the walls, ceilings, floors & avoid comb filtering.
Not only does the effects of mixing two signals out of time result in a frequency response trace that looks like a comb, the word “combine” can also be used to remember what is going on to cause this effect.
Combining filter anyone?