Speaker placement calculator for stereo, 5.1 and 7.1
Good placement costs nothing and often does more than new equipment. This speaker placement calculator finds a listening seat with the 38% rule or the rule of thirds, builds the stereo triangle, places 5.1 and 7.1 surround speakers at the angles in ITU-R BS.775 and BS.2051, and compares subwoofer positions by how strongly they excite your room’s main bass modes.
You get distances from the front and side walls, a scaled room plan, and the delay and level trim for any speaker that has to sit closer than the rest. It works for home cinemas, hi-fi rooms and studio monitors, in metres or feet, in your browser.
How to use the Speaker Placement Calculator
- Choose Stereo, 5.1 or 7.1 and enter the room’s length (from the wall the speakers face out from) and width.
- Pick a seat rule: 38% of the length, the rule of thirds, or your own distance.
- Enter how far the front speakers stand from the front wall, and adjust the surround angles if you like.
- Read the positions, check the plan, and compare the subwoofer options in the last table.
Speaker Placement Calculator features
Seat rules
38% of the room length or the rule of thirds, with warnings for the room centre and the back wall.
Stereo triangle
Speakers at ±30°, as far apart as they are from the seat, toed in towards you.
5.1 and 7.1 angles
Surrounds at 100–120° for 5.1; sides at 85–110° and rears at 120–150° for 7.1.
Wall fallback
Speakers that would be outside the room move to the wall, with delay and level trim.
Subwoofer comparison
Six one-, two- and four-sub layouts scored on the first two length and width modes.
The rules behind the numbers
- Stereo: ITU-R BS.775 puts the left and right speakers at the ends of a 60° arc seen from the seat (±30°), so they are as far apart as the seat is from each of them.
- 38% rule: a seat about 38% of the room length from the front wall sits away from the pressure null of the first length mode at 50% and the peak at the back wall. Some apply it from the back wall instead; both avoid the same problems.
- Rule of thirds: speakers one third of the way into the room and the seat two thirds in.
- 5.1: centre at 0°, left and right at ±30°, surrounds at ±100–120° (110° nominal), all at the same distance where possible (ITU-R BS.775-4; BS.2051-3 System B).
- 7.1: side surrounds at ±90° (85–110°) and rear surrounds at ±135° (120–150°), 30–60° apart on each side (ITU-R BS.2051-3, System I).
Worked example
In a 5.5 × 4.2 m room the 38% rule puts the seat 2.09 m from the front wall. With the front speakers 0.6 m out, each is 1.72 m from the seat and they stand 1.72 m apart, 1.24 m from the side walls. For 5.1 the surrounds go at ±110°, about 0.6 m behind the seat and close to the side walls; a centre in line with the left and right speakers is 23 cm closer, so it gets 0.7 ms of delay.
Subwoofer placement
Bass below about 100 Hz is dominated by room modes. Each axial mode has a pressure peak at the walls and nulls between them, so a subwoofer at a null cannot drive that mode. Two subs at the centres of opposite walls cancel the first length and first width modes, and four subs at the centre of every wall cancel the first two of each, which is why multiple-subwoofer studies (Welti, AES 2002) recommend them. A single sub in a corner gives the most output but drives every mode. Try the “subwoofer crawl”: put the sub at your seat, play bass and crawl around the room’s edge to find where it sounds smoothest. The room mode calculator lists every mode, and the speaker test plays test tones.
Speaker Placement Calculator FAQ
Where should I put my speakers in a room?
Form an equilateral triangle with your seat, keep the speakers at least 0.5 m from side walls, and sit about 38% of the room length from the front wall. This speaker placement calculator works out the distances for your room.
What are the speaker angles for 5.1 surround?
Centre at 0°, front left and right at ±30°, and surrounds at ±100–120° (110° nominal), measured from straight ahead at the seat.
Where do the extra speakers go in 7.1?
Side surrounds at about ±90° and rear surrounds at about ±135°, all at ear height.
How far should speakers be from the wall?
Typically 0.5–1 m from the front wall and at least 0.5 m from side walls. Closer boosts bass and strengthens reflections; very close (against the wall) can work for speakers designed for it.
Where should I put a subwoofer?
One sub in a front corner is loudest; two subs at opposite wall centres give smoother bass across seats. The table shows how each option drives your room’s first modes.
Does this work for studio monitors?
Yes. Use stereo, set the monitors’ distance from the front wall, and keep the tweeters at ear height and the triangle equilateral.