Speaker Placement Calculator

Room Width is what the 20% pull-in rule (Speaker from Side Wall) and the resulting Speaker Spread are both calculated from directly, and because an equilateral stereo triangle ties Listener Distance and Stereo Angle to that same spread, the effect of Room Width cascades through most of the results. Room Length only feeds Speaker from Front Wall and Listener From Front, and Listener from Back Wall only feeds Listener From Front -- narrower roles that don't ripple into the stereo-triangle calculations.

A 60-degree angle between the listener and the two speakers is the classic recommendation for accurate stereo imaging, corresponding to an equilateral triangle where the listener sits exactly as far from each speaker as the speakers sit from each other. This calculator's Speaker Spread and Listener Distance are set equal by construction, so Stereo Angle always computes to exactly 60 degrees regardless of your room's dimensions -- it's a fixed property of the equilateral-triangle model itself, not an estimate that drifts with room size. If your actual listening position differs from that ideal triangle, treat that as a cue to adjust speaker toe-in or listening distance.

Using a percentage rather than a fixed number of feet lets the pull-in distance scale sensibly across very different room sizes -- a narrow room and a wide room both get a proportionally similar amount of side-wall clearance rather than the same fixed distance being too little clearance in a wide room or leaving no usable spread in a narrow one. 20% is a commonly cited starting point for balancing bass response against usable speaker spread.

Surround Distance estimates rear-channel placement as 80% of Listener Distance, reflecting the common guidance that surround speakers sit somewhat closer to the listener than the front stereo pair, typically angled 110 to 120 degrees off center. It's a rough starting distance for a home theater layout, not a substitute for your AV receiver's speaker calibration or the specific surround format's placement recommendations.