acoustic insulation Applications

Sound energy does not remain in the room where it is produced, but propagates throughout the building by any available path, intruding into other rooms as noise. Each country has its own standards of sound insulation in buildings, but it is measured in the same way all over the world. The noise levels in the two rooms under investigation are measured and subtracted, and the level difference is corrected for the influence of the reverberation time and background noise level in the receiving room. The measurements and calculations are made in 1/1- or 1/3-octave bands and averaged over a number of positions in the rooms. Finally a single-number index is calculated by averaging over all the frequency bands.

By Brüel & Kjær Sound & Vibration Measurement A/S based in Nærum, DENMARK.

Façade sound insulation is measured like sound insulation between rooms, except that one `room` is actually open space. The sound level is measured inside the receiving room and outside the façade of the building. The level difference is then corrected for the influence of the reverberation time and background noise level in the receiving room. Finally a single-number index is calculated by averaging over all the frequency bands. A loudspeaker source can be used for the measurement, giving a choice of sound incidence angle. But in practice, placing the loudspeaker and getting a high enough sound level can be difficult.

By Brüel & Kjær Sound & Vibration Measurement A/S based in Nærum, DENMARK.