How to choose acoustic panel thickness for a meeting room

Most enquiries we receive specify a thickness before anyone has agreed what the room is for. That is backwards. Thickness is an acoustic decision, and it is much cheaper to make it correctly at the quotation stage than to discover the room still echoes after the panels are on the wall.

Start with the complaint, not the panel

Three complaints sound similar and need different answers:

• "People cannot hear each other in meetings." This is a reverberation problem. Absorption on two opposing walls fixes most of it.
• "It is too noisy in here." This is usually a sound source problem — the photocopier, the open plan, the traffic outside. Panels on the wall may barely help.
• "I can hear the meeting next door." This is sound transmission, not absorption. A wall panel does almost nothing. You need mass, sealing and a decoupled partition.

Only the first case is a straightforward acoustic panel job. If your client has the third complaint and you sell them 300 m² of felt-backed slats, you will be back on site six weeks later.

The thickness ladder

Our builds go 9, 11, 16, 18 and 21 mm. The felt behind the slats gets thicker and denser as you go up, and that is where absorption comes from:

• 9 mm (DT-1) — NRC 0.75–0.80. Corridors, lift lobbies, thin renovation walls where the finished wall cannot grow.
• 11 mm (DT-2) — NRC 0.75–0.80. The general-purpose thickness. Offices, restaurants, classrooms, retail.
• 16 mm (DT-3) — NRC 0.80–0.85. The point where meeting rooms and classrooms stop being hard work.
• 18–21 mm (DT-4, DT-5, YX) — NRC 0.80–0.85, for studios, worship halls, ballrooms, atriums — anywhere the panel is a design feature rather than a wall lining.

Note how narrow the NRC range is between 11 mm and 21 mm. A single-number rating suggests a big jump that is not there. What changes more is the low-frequency behaviour and the visual weight of the panel.

Coverage matters more than thickness

This is the part that gets missed. In a 6 × 4 m meeting room:

• 30% of the wall in 16 mm: the room becomes usable. Speech is clear, people stop leaning forward.
• 60% of the wall in 9 mm: usually also usable, and cheaper.
• 100% of the wall in 21 mm: the room feels dead and tiring. People start talking loudly to compensate, which raises the noise floor.

Coverage and thickness trade against each other. Do not spend on the thickest panel and then treat a quarter of the wall.

The mounting method is a third variable

A 21 mm panel bonded flat to a plasterboard wall absorbs the speech band well and bass almost not at all. The same panel on 50 mm battens absorbs noticeably lower in frequency. If your client complains about boom rather than echo, specify battens — a thinner panel with a cavity beats a thicker panel glued flat, at a lower price.

Our installation guide covers the three mounting methods and when each one is right.

A workable decision sequence

1. Identify the complaint. If it is transmission, stop — a panel will not fix it.
2. Decide coverage from the room type. Our applications page has starting percentages per room.
3. Set thickness from the coverage you can afford and the acoustic difficulty of the room.
4. Choose mounting: direct fix, battens, or frame — driven by bass performance and wall flatness.
5. Only then pick the finish and the pattern.

Following that order, a meeting room enquiry takes one exchange to quote instead of four.

What we will ask you

To quote properly we need the wall area or the room dimensions, the room type, the floor and ceiling materials, and the complaint in one sentence. Send a photograph of the room if you have one — it is worth a page of description.