Alternative method to determine the residual sound in quiet zones, quiet residential areas, or describing soundscapes

It is important to know the residual sound in a location to estimate the impact of noise sources prior to their installation, but not only the dBA sound level should be known, it should also be important to know its one-third octave band levels. For describing or measuring residual sound levels in quiet areas, an ANSI/ASA standard recommends procedures adapted to get a single unit in dBA, but not intended to characterize the sound in specific quiet spots or natural places. Wind turbines, pumping and compression stations for natural gas facilities, and other industrial facilities with high levels of low-frequency noise are usually installed near wilderness areas, so it is important to have a description of the entire soundscape in terms of sound spectrum rather than just a single dBA value. An empirical method was developed using measurements recorded in 125-ms samples, to estimate the residual sound levels based on a 90th (or other value) percentile sound level like a threshold, an algorithm rejects those samples above it and keeps those below, then a new spreadsheet is generated with the lowest sound levels contained in the original file, in that way not only the lower L Aeq,T value is obtained but also L Ceq,T, L Zeq,T, full spectrum, and other noise descriptors.