Break-up or distortion of a sound wave created when the sound wave hits a speaker cabinet, grille cover, or other similar component of the speaker that is creating the sound. Imagine you tap a surface of water in the sink with your hand at the edge of the sink. Waves will ripple out from where you hit the water with your hand spreading out in all directions from that initial point just like sound waves. Watch as those waves hit the edge of the sink where you started the waves by hitting the water. The waves will hit the side of the sink and break up or distort in relation to the other waves moving across the sink. In this example, the side of the sink is causing diffraction. Diffraction is common in speaker systems but is minimized through good designs. Some speakers use baffles that curve away from the drivers to decrease diffraction while others use specially designed grille covers to combat diffraction.