Where to put acoustic panels: the mirror method, height and coverage

How many panels you hang matters. But where you hang them matters almost as much. The same panels placed thoughtfully work noticeably better than panels hung wherever there was a gap. This guide collects the rules that work in a home office, a living room, a recording corner and a home cinema.

The general rule

Panels do most where sound reflects for the first time on its way from the source to the listener or microphone. Those are the first reflection points. Once they’re covered, spread the remaining panels around the room to shorten the overall reverberation. First reflection points first, even coverage second.

The mirror method

First reflection points are easiest to find with a second person and an ordinary small mirror:

1. Sit or stand where you usually listen or speak – at the desk, on the sofa, at the microphone.
2. Ask the other person to hold the mirror flat against a side wall at the height of your ears.
3. Have them slide it slowly along the wall. When you can see the sound source in it – a speaker, the monitor or the microphone – mark the spot in pencil.
4. Repeat for every source and every wall, including the walls in front of and behind you.

The marks are the centres of your panels. The panel doesn’t need to land exactly on them – it’s enough for the marked point to fall somewhere on its surface.

Mounting height

The centre of a panel should be roughly at ear height, because that’s where most of the reflections you hear pass:

• at a desk or on a sofa: about 110–130 cm from the floor,
• standing, for example at a singing microphone: about 150–170 cm,
• in arrangements of several panels: a shared top or bottom edge, with the centre of the group at ear height.

How much wall to cover

A good starting point is to cover 15–30% of the wall area. Less than that is hard to notice in an ordinary room; more is useful in recording rooms and home cinemas. You can estimate it more precisely with the calculator, which works out the reverberation before and after the panels go up.

Don’t put everything on one wall

If all the panels go on one wall, the opposite wall stays smooth and sound keeps bouncing off it. It’s better to spread the panels over two or three walls. Where two bare walls face each other, one panel on either of them is enough to break up flutter echo – the quick repeats you hear when you clap your hands.

Symmetry

Where you listen to music or watch films, place panels symmetrically on the left and right. Otherwise one side of the stereo image sounds different from the other. Symmetry helps visually too: the arrangement looks calmer and the panels feel like part of the room.

Gaps between panels

Gaps of 5–15 cm between panels look tidy and don’t reduce their effect. The edges of the panels absorb sound too, so several smaller panels spread out with gaps absorb about as much as, or even slightly more than, one large panel of the same total area. Because you set sizes to the centimetre, you can match the gaps to the width of the wall.

The gap behind the panel

The panel hangs on a French cleat, which holds it off the wall. The air gap behind it isn’t wasted space: sound that has passed through the wool reflects off the wall and goes through it a second time, which improves absorption at lower frequencies. There’s more on this in our guide to 5 or 10 cm.

Plan it on paper

Before you start drilling, draw each wall to a simple scale – 1 cm on paper to 20 cm on the wall, for example. Mark the windows, doors, sockets, switches, radiators and any furniture against the wall. Then add the first reflection points you found with the mirror and try to arrange the panels so they cover those points while following the lines of the furniture and windows.

A drawing like this makes it easy to see whether the arrangement is symmetrical, whether the gaps are even and whether a panel would land over a socket or a radiator. It also makes it easy to add up the total panel area and compare it with the calculator. You can then take the sizes straight into the configurator – each panel can have its own size, fitted to its spot.

Corners

Corners, where two walls meet – and especially where two walls meet the floor – collect the most low-frequency energy. A 10 cm panel hung close to a corner absorbs more there than in the middle of a wall. It won’t replace dedicated bass traps, but in rooms that boom, it’s worth starting with panels near the corners behind the listening position.

Examples for different rooms

Home office. Start with the wall in front of you, behind the monitor, and the wall behind you – both at seated head height. Then the first reflection points on the side walls. Usually four to six panels in total.

Recording corner. A panel behind your head, in line with the microphone, a panel in front of you behind the microphone, and one on each side wall. Ideally 10 cm.

Living room. Arrangements on two or three walls: above the sofa, by the table, on a large bare wall. Shared edge lines, with the centre of each group at the head height of people sitting down.

Home cinema. First reflection points on the side walls, panels behind the speakers and on the back wall. Symmetrical on the left and right.

Common mistakes

• Panels hung wherever there was space rather than where sound reflects.
• Every panel on one wall, with bare glass or plaster opposite.
• Panels too high, above the listeners’ heads.
• One small panel where several square metres of absorbing surface are needed.
• No symmetry where you listen to music.

In short

First find the first reflection points with the mirror method and hang panels there, centred at ear height. Then spread the rest over two or three walls so they cover 15–30% of the wall area in total. Keep things symmetrical where you listen to music and films, and keep shared edge lines in arrangements. Plan it all on paper before you drill, and fit the panel sizes to your walls, furniture and windows.