The noise reduction coefficient ranges between 0 40 and 0 75 depending on the slot pattern and installation.
Absorption coefficient of hardwood.
Generally speaking soft porous materials will be more absorptive than hard reflective surfaces.
Absorption coefficients are an average of how absorptive each product is at numerous frequencies generally at 500 hz 1000 hz and 2000 hz.
In general when sound waves strike on the surface of porous materials sound energy could get channelized as.
The measured aerosol absorption ångström exponent aae at 370 880 nm aae 370 880nm was 1 71 0 24.
Sound absorption properties of wood have a close relationship with their micropores structure and gas permeability.
Plywood hardwood panels over 25mm airspace on solid backing 0 30 0 20 0 15 0 10 0 10 0 05 solid backing with absorbent material in air space 0 40 0 25 0 15 0 10 0 10 0 05.
The length and pattern of the slots cut through the panels influence their absorption of soundwaves.
Slotted wood panels can be used on walls or ceilings to reduce the noise and echo within a room or building.
Hardwood burning was identified as the dominant source of carbonaceous aerosols.