Application of new measurement method in building and room acoustics.
The classical methods of determining the sound transmission between rooms have been with us for some time and their limitations are well known mostly due to background noise being too high.
These difficulties are now recognised by the standards authorities and in response they have published the BS EN ISO 18233:2006 Acoustics – “Application of new measurement methods in building and room acoustics”. This standardises measurement procedures based on deterministic signals that can be used to obtain the impulse response of the test space which in turn may be post processed to give both the level difference and reverberation time.
Two methods have been standardised and these may be used as alternatives for the classical methods described in BS EN ISO 140 (all parts) BS EN ISO 3382 (all parts) and ISO 17497-1 when determining the reverberation time or level difference for calculation of sound insulation parameters as per BS EN IEC 717 series of standards
- The MLS method described in annexe A is implemented in the Nor-840 analyser and is best suited to controlled conditions such as test laboratories etc.
- The Swept-sine method described in annexe B is implemented in the Nor-121 analyser and as this is more robust in terms of test environment and resistance to harmonic distortion is recommended for field application