Speaker Placement Calculator

Speaker placement has a dramatic effect on sound quality, often more than upgrading the equipment does. Proper positioning creates a wide, focused stereo image with balanced frequency response.

The stereo triangle: The two speakers and the listening position should form an equilateral triangle. Each side of the triangle should be the same length: the gap between the speakers equals the distance from each speaker to your ears. The speakers should be angled inward (toed-in) to face the listening position.

Toe-in angle: Typically 15-30 degrees inward. Start with both speakers pointing at a spot about 1-2 feet behind your head and adjust by ear. On a true equilateral triangle, aiming straight at your ears is exactly 30 degrees, and crossing the axes behind your head opens that out a little.

Distance from walls:

• Side walls: At least 2 feet (60 cm). The further from side walls, the less comb filtering and reflections.
• Back wall (behind speakers): At least 2-3 feet (60-90 cm). This reduces bass boom and improves midrange clarity.

Listening position:

• Sit at approximately 38% of the room length from the front wall. This is the classic Cardas figure and it is about room modes: 38% is the spot that sits furthest from the worst peaks and nulls of the length modes.
• Avoid sitting against the back wall. That exaggerates bass badly.
• Ears should be at tweeter height.

Where the two rules collide

You will see a separate “rule of thirds” that puts the speakers a third of the room length off the front wall. Apply that and the 38% seat rule together and the arithmetic falls apart: in an 18-foot room the speakers land at 6.0 ft and the seat at 6.84 ft, which puts your ears ten inches behind the speaker plane. That is not a triangle, it is a line.

The seat rule is the one to keep, because it is fixed by the room’s modes and you cannot argue with those. The speakers then go wherever the equilateral triangle demands, which is 0.866 × the spread in front of your seat. The calculator above works it out that way, and tells you which wall ran out of room first.

Room modes (bass peaks and nulls): Bass frequencies create standing waves in rectangular rooms. Sitting at room center or at 50% points along any dimension puts you in a bass null. Sitting at 25% or 75% points along room dimensions often gives more even bass.

Speaker height: Tweeters should be at ear height when seated, typically 36-40 inches (91-102 cm) off the floor. Note that this is the tweeter height, not the stand height. A bookshelf speaker’s tweeter sits 9-11 inches above its base, so a 26-30 inch stand gets you there. If on a desk, the surface alone is already about 29 inches, so the tweeter usually ends up too high. Tilt down rather than up.

Subwoofer placement: The “subwoofer crawl” method works well: place the sub at your listening position, then crawl around the room perimeter to find where the bass sounds best. Place the sub there.