Does anyone happen to know how to calculate or estimate the audible noise level of products (A-weighted) before they are built?
One assumption that I have made is that continuous acoustical noise from numerous identical devices add together in the same way that power does. IOW, two identical fans, with a 50 dBA rating, would measure 53 dB. Is this correct? Does this represent a worst-case estimate? Or, IOW, in an actual system with 10 fans, for example, would some of the noise cancel out due to phase angle differences in the emissions from the fans? Another question that I have is if emissions at different frequencies add together like power. For example, would 50 dBA "noise" emissions, at 15 Khz, from a violin add together with 50 dBA emissions, at 20 Hz, from an organ to make a total measured emission of 53 dBA? Or would a meter measure only 50 dBA in this situation? Or more specifically, has anyone had any experience with power supply fans and system cooling fans? Does the noise from these two different types of fans typically add together? Max Kelson Evans & Sutherland
