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

(often cited as the 2022 international version) is the primary standard for measuring room acoustic parameters in unoccupied open-plan offices . Unlike Part 2, which focuses on temporal decay (reverberation), Part 3 focuses on spatial decay , or how sound levels drop as you move away from a speaker. Key Acoustic Parameters

): The reduction in sound pressure level (dB) when the distance from a speaker is doubled. Speech Level at 4 Meters (

Lp,A,S,4mcap L sub p comma cap A comma cap S comma 4 m end-sub

): 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