): The distance from a speaker where the Speech Transmission Index (STI) falls below 0.50, the point at which concentration starts to improve. Background Noise Level ( Lp,A,Bcap L sub p comma cap A comma cap B end-sub
The standard defines several single-number quantities to evaluate acoustic performance: Spatial Decay Rate of Speech ( D2,Scap D sub 2 comma cap S end-sub DIN EN ISO 3382 3 E 2021 02 pdf
): The A-weighted sound pressure level of speech at a 4-meter distance, indicating how much nearby surfaces reflect sound. Comfort Distance ( rCr sub cap C ): The distance from a speaker where the
Lp,A,S,4mcap L sub p comma cap A comma cap S comma 4 m end-sub DIN EN ISO 3382 3 E 2021 02 pdf