Weighted sound insulation index of pressure casing – reciprocity method

Professional Definition

Weighted sound insulation indicator of the pressure case – reciprocity method – pressure sound insulation in the standard frequency range reduced to a single numerical value according to the method provided in PN-EN ISO 717-1.

This definition combines two aspects. First, it refers to the reciprocity method, which is a measurement technique that allows swapping the source and the receiver (often used when the physical placement of the noise source inside a small case is impossible). Second, the ISO 717-1 weighting procedure is crucial here. It allows transforming insulation values obtained for different frequency bands (1/3 octave or octave) into a single numerical value (index), facilitating product classification.

Acoustics in Simple Words

It’s like the energy rating of a refrigerator (class A, B, C), but for a soundproofing casing. Instead of analyzing a complicated graph that says the casing dampens bass well but performs worse with squeaks, you get one numerical result. The reciprocity method is, in turn, a clever engineering trick: instead of putting a speaker in a cramped case to see how sound escapes outside, we can (in simplified terms) emit sound from the outside and measure it inside, and physics guarantees us that the resulting insulation will be the same. It’s like checking the tightness of a pipe – it doesn’t matter from which side you pour the water, the hole will leak the same.

Summary

This is a single numerical evaluation of the effectiveness of sound-absorbing and insulating casing, determined based on measurements using the reciprocity method. It allows for quick comparison of products according to the PN-EN ISO 717-1 standard, reducing complex spectral data to one reliable indicator.