Technical Booklet G Resistance to the Passage of Sound·Page 119·B2.8
Multiple sources spectrum requirements
For multiple simultaneous sound sources, the difference between average sound pressure levels in adjacent one-third octave bands in the source room must not exceed 6 dB, with the same adjustment and repeat procedure as for single sources.
For the source room measurements, the difference between the average sound pressure levels in adjacent one-third octave bands should be no more than 6 dB. If this condition is not met, the source spectrum should be adjusted and the source room measurement repeated. If the condition is met, determine the average level in the receiving room, and hence the level difference, D as defined in BS EN ISO 140-4.
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