What is acoustic treatment in a meeting room?

Acoustic treatment is the use of absorption, diffusion and reflection control materials to manage how sound behaves in a room, with the goal of bringing reverb time (RT60) into the 0.4 to 0.6 second range that gives clean speech intelligibility on video calls. Untreated meeting rooms with glass, drywall and hard floors often run 0.8 to 1.2 seconds, which is the main reason rooms sound "echoey" or "boomy" on conference calls.

The three categories of treatment, with what each does:

• Absorption. Soft materials that convert sound energy to heat. Acoustic ceiling tiles (Rockfon, Armstrong, Ecophon), wall panels (fabric-wrapped fibreglass or PET felt), ceiling baffles and clouds, and carpet. Absorption is the dominant tool for reducing RT60 across the speech frequency band (500 Hz to 4 kHz).
• Diffusion. Decorative or geometric surfaces that scatter reflected sound rather than absorb it. Wood slat panels, sculpted PET diffusers, even bookshelves with mixed-depth contents. Diffusion preserves liveness while removing the slap-back of flat hard walls.
• Reflection control. Soft furnishings that block first reflections off hard surfaces. Carpet on the floor, curtains over glazing, upholstered chairs (rather than hard plastic), large planters or screens between glass walls.

A typical commercial meeting room treatment package:

• Acoustic ceiling tile system rated NRC 0.85 or higher (the Rockfon Sonar or Ecophon Master families are common UK choices).
• Two to four fabric-wrapped wall panels of 50mm thickness on the back and side walls, each roughly 1.2 m by 0.6 m, placed at first-reflection points relative to the camera and mics.
• Carpet tiles or low-pile carpet on the floor.
• Curtains or motorised blinds across any large glazed wall, drawn during calls.

Cost varies with the level of intervention. A light treatment (ceiling tiles plus a few wall panels) sits around £500 to £1,500 for a standard meeting room. A full treatment for a glazed boardroom (acoustic ceiling, multiple panels, baffles, motorised blinds) can run £1,500 to £3,000+. The numbers are small relative to the AV budget but produce a disproportionate improvement in remote participants' experience of the room.

What you don't need: studio-grade bass traps, full anechoic absorption or "soundproofing". Meeting rooms are not recording studios; the goal is to manage reflections so the microphones pick up speech cleanly, not to achieve silence. Over-treating a room produces a deadened, oppressive feel that participants dislike.

The best time to specify acoustic treatment is during the meeting room AV design phase, alongside ceiling-mic and speaker layout, because the treatment, the mic placement and the DSP tuning all interact. A specialist consultation and design brief will resolve them together rather than treat acoustics as an afterthought.

Quick reference: target RT60 of 0.4-0.6 seconds for clean VC speech; mix of absorption (acoustic ceiling tiles, fabric-wrapped wall panels, carpet), diffusion (wood slat or PET panels) and reflection control (curtains, soft furnishings).