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Speaker Placement Optimizer

Enter your room size and get a proven starting layout: the 38% listening position, an equilateral stereo triangle, speaker separation, side- and front-wall distances, toe-in, and where to put the subwoofer — with a top-down diagram.

ℹ These are well-known rules of thumb, not laws. They assume a rectangular room with the speakers on the front (short) wall, firing down the length, and a symmetric setup. Left/right symmetry matters most — keep each speaker the same distance from its side wall. Rooms, speakers and tastes vary, so treat this as a great place to start and then trust your ears (and a measurement — see the Room Frequency Analyzer). All maths run in your browser.

How It Works

The calculator places your listening seat at 38% of the room length from the front wall — a position (popularised by George Cardas) that tends to sit between the worst low-frequency modal peaks and nulls along the length of the room. It then builds an equilateral triangle: the distance between the two speakers equals the distance from each speaker to your ears, which works out to about 30° of toe-in when you aim the speakers at your head. From your chosen speaker-to-front-wall distance it also reports the SBIR (speaker-boundary interference) cancellation frequency, f = c / (4·d), where a reflection off the wall behind the speaker arrives a half-wavelength late and partially cancels — one of the biggest causes of a suck-out in the bass.

Two things matter more than hitting these numbers exactly. First, symmetry: the left and right speakers must be the same distance from their nearest side wall, or the stereo image and bass response will differ side-to-side. Second, your room’s modes: the 38% seat and the front-wall distance interact with standing waves, so confirm the result by ear and, ideally, with a measurement. Use the diagram as a map, set it up, then nudge the seat and speakers a few centimetres at a time while listening to a familiar bass-heavy track.

Frequently Asked Questions

Should speakers go on the long wall or the short wall?
This tool assumes the common setup: speakers on the front (short) wall, firing down the length of the room. Firing across the width can work and shortens early side reflections, but it usually leaves little room behind the listener — try both if you can, and keep it symmetric either way.
Why 38%?
Across typical room proportions, ~38% of the length tends to avoid sitting right on a major length-mode peak or null. It’s a strong starting point, not a guarantee — your room’s exact modes may shift the best seat a little.
What is toe-in?
Angling the speakers inward so they aim at (or just behind) your head. The equilateral triangle implies about 30°. More toe-in tightens the centre image and reduces side-wall reflections; less widens the soundstage. Adjust to taste.
What is the SBIR frequency?
Speaker-Boundary Interference Response: the reflection off the wall behind a speaker cancels with the direct sound around f = c/(4·d), where d is the speaker-to-wall distance. A speaker 0.5 m out has a dip near 170 Hz. Move speakers much closer to (or further from) the wall to shift that dip out of the way.
Where should the subwoofer go?
A corner gives the most output but excites every room mode. Along the front wall, off-centre, is a good compromise. The most reliable method is the “sub crawl”: play a bass loop from the sub placed at your seat, crawl the room, and put the sub wherever the bass sounded smoothest.