The 83% rule is a popular acoustic rule of thumb—frequently attributed to expert audio setup consultant Jim Smith—used by audiophiles to determine the optimal speaker placement in a dedicated listening room. The guideline states that the direct distance from one's ears at the primary listening position to either speaker should equal approximately 83 percent of the distance separating the two speaker tweeters from one another. Expressed mathematically as a ratio, the distance between the tweeters divided by the listening distance should equal roughly 0.83, helping enthusiasts achieve an equilateral or slightly wide-angle stereo triangle that maximizes soundstage imaging, depth, and spatial coherence.