Impact sound insulation
The impact sound pressure levels that can be obtained with homogeneous massive plates can be described theoretically by the sound radiation from point excitation of plates. However, supplementary attenuation of the impact sound pressure level is normally necessary. This can be done by soft resilient floor coverings or by elastically layered floating floors, which can be considered double constructions. Floating floors tend to improve the impact sound insulation more than the airborne sound insulation. With a carpet or some other thin flooring, e.g. linoleum with soft underlay, a reduction of the hammer force of the floor is obtained by decreasing the speed gradually from maximum at the surface to zero when a certain pressure is reached in the flooring, after which the hammer returns to the surface level. The course corresponds to half a cycle for a mass-spring system where the spring constant is determined by the modulus of elasticity of the flooring, its thickness and the actuated area.