Walls in lecture halls are usually drywall, block or glass, all of which reflect almost all of the sound that reaches them. Assembly occupancy: finishes in exits and corridors must be Class A, and many jurisdictions require Class A in the room itself.
Treat reflection points first
A reflection point is a spot on a wall where sound from a source bounces to a listener. You can find them with a mirror: sit where people listen, have someone slide a mirror along the wall, and mark each spot where you can see a sound source. Panels there give the biggest improvement per square foot.
Parallel walls and flutter echo
Two bare parallel walls make a fast, buzzing echo when you clap. One panel on each wall, offset from each other, usually stops it. See flutter echo between drywall walls.
Recommended wall products
- Groove: Corporate lobbies, auditoriums, offices, from $77
- Facet: Lobbies, showrooms, auditoriums, from $102
- Swell: Feature walls, worship spaces, hotels, from $143
If the wall needs to block sound too
Panels do not add meaningful STC to a wall. If sound coming through the wall is a problem, read soundproofing and STC for lecture halls and what STC means.