Caveat emptor. How often have we heard that? Would you buy a car based on “average” fuel consumption, and then act surprised if you consume more fuel than you expected? We pride ourselves, do we not, when we are smart buyers, when we educate ourselves as much as possible.
If you’re involved in a review of a new facility, make sure you understand the full extent of the potential noise levels. I will warn you right now: the developer and the manufacturers may not know! Testing “standards” and test stand conditions may differ from and, end up hiding, the true extent of the noise produced “in the real world.”
Always wonder what a manufacturer is hiding when they use A-weighting.
Always wonder what a manufacturer is hiding when they use averaging.
The A-weighted sound level does not contain the low frequency information. Averaged data do not show the peak or maximum sound levels produced by the equipment. Most community noise issues involve low frequency or peak, impulsive noise impacts. Field measurements of similar facilities may be essential to understand the low frequencies, the peaks, and the time-varying noises that equipment produce “in the real world”. Insist on unweighted data. If the manufacturer doesn’t have peak or maximum levels, insist they be furnished, preferably from a similar facility.
–thanks to sengpielaudio.com for the quotable quote! -ed.