Please help with these problems for sound pressure level for sound and acoustics
ID: 1717721 • Letter: P
Question
Please help with these problems for sound pressure level for sound and acoustics control
On a shop floor, during the day shift, there are 16 milling machines. The average reverberant sound pressure level was measured at 96 dBA (re 20 mu Pa). On the night shift, only 3 of these same machines are running. What is the reverberant SPL in the shop at night? You visit a customer in an office building. There is HVAC noise from the vent near their desk that you are asked to evaluate. At your initial meeting, all you have is your smart phone with a "cheap" SLM app. Explain, how by using only the app, you can establish whether adding absorption to the room would produce significant reductions at the desk position.Explanation / Answer
Day shift - Number of milling machines = 16
Avg Rev sound pr level = 96 dBA
Sound pr level / machine = 96/16 = 6 dBA average
In night shift 3 machines are running so Reverberant SPL = 3 x6 = 18 dBA