Combfiltering

Combfiltering is the result of two or more signals with differential timing being summed. The difference in time between the two signals results in different phase relationships at different frequencies with the component signals summing where they are in phase and cancelling where they are 180 degrees (or one half wavelength) out of phase. The result is a summed frequency response with distinct peaks and valleys that resembles a comb.

Combfiltering is commonly associated with the same signal being reproduced by mutliple speakers or drivers that are physical separated or in relation to multiple microphones picking up common sources but with some difference in distance from the source.