Sound waves emitted from the rear of a loudspeaker are 180 degrees out of phase with those emitted from the front. Consequently, when the loudspeaker's diaphragm advances, creating a compression wave at the front, it simultaneously generates a rarefaction wave at the rear, and vice versa.
This phase disparity leads to destructive interference between the front and rear sound waves if not managed correctly, potentially diminishing the overall sound output or canceling specific frequencies. Loudspeaker enclosures are therefore engineered to counteract this destructive interference and improve sound quality.