Project quote: Price the whole project

Echo time = 0.161 × V ÷ A. V is the room’s volume (length × width × height, in m³). A is how much sound the room soaks up (in m²): each surface’s area times its absorption number, plus 0.435 m² for each person. This is Sabine’s formula.

Acouline panels are rated NRC 0.85 (supplier data). A panel covers wall that was already soaking up a little, so each square metre of panel adds 0.85 minus that wall’s own number. One full-size panel is 1200 × 2800 mm; in a room lower than 2.8 m it’s trimmed to the ceiling. We round up to whole panels, and keep 1.7 m² of wall free for a door.

Absorption numbers: the average of the 250, 500, 1000 and 2000 Hz columns of the published table.

Surface	Absorption
Floor: CarpetCarpet, thin, over thin felt on concrete	0.25
Floor: TimberWooden floor on joists	0.085
Floor: TilesCeramic tiles with smooth surface	0.015
Floor: Vinyl / linoLinoleum or vinyl stuck to concrete	0.0325
Floor: Polished concreteSmooth unpainted concrete	0.0175
Walls: PlasterboardPlasterboard on frame, 100 mm airspace	0.08
Walls: Brick / blockSmooth brickwork with flush pointing	0.0375
Walls: ConcreteSmooth concrete, painted or glazed	0.015
Glass and windows6 mm glass	0.0375
Ceiling: PlasterboardPlasterboard on frame, 100 mm airspace	0.08
Ceiling: ConcreteSmooth concrete, painted or glazed	0.015
Ceiling: Acoustic ceiling tilesMineral wool tiles, 180 mm airspace	0.83
Each personAdults, seated	0.435 m²

• Open-plan office: 0.5 s. The WELL Building Standard (feature 78) asks for 0.5 s or less in open workspaces.
• Meeting / board room: 0.6 s. The WELL Building Standard (feature 78) asks for 0.6 s or less in conference rooms.
• Classroom / training room: 0.6 s. The WELL Building Standard (feature 78) asks for under 0.6 s in learning spaces up to 3,000 m³.
• Café / restaurant: 0.8 s. The middle of the 0.6–1.0 s range AS/NZS 2107 gives for bars and lounges, as reported by the Australian Acoustical Society.
• Home office / study: 0.6 s. Our pick: the same as a meeting room.
• Other: 0.6 s. Our pick: the same as a meeting room.

These targets are a guide to a comfortable room. This tool doesn’t check or certify that a room meets any standard.

Sources: table of sound absorption coefficients (PDF); WELL Building Standard, feature 78; Burgess and Gabriels, “Overview of the revision of AS/NZS 2107”, Australian Acoustical Society (PDF); Acouline panel rating NRC 0.85: our supplier’s product data.