How to use a sound level meter? What are the techniques?
Check the time on the sound level meter
During most measurements, a report-relevant event is recorded, usually by recording the time of the event via a watch or mobile phone. It is important that the time on the sound level meter matches your timepiece so that your notes will match what is recorded on the sound level meter. This becomes especially important when using two or more sound level timers.
Set up logging and reporting cycles
Some standards and regulations specify specific measurement intervals. If your sound level meter supports recording at multiple time intervals (called recording and reporting periods on Brüel & Kjær sound level meters), consider setting the reporting period according to the standard requirements, and the recording period should be shorter. This way, you have the convenience of directly measuring the values required for reporting and the ability to investigate and correct short-term disturbances. This will make it easier for you when you start writing your report.
Check if you have enough free data storage
This is a very basic point, so it's easy to forget: remember to check if there is enough free space on the memory card for the upcoming measurement. It is a good practice to regularly delete old measurement data after it has been safely downloaded and stored, as is keeping a spare memory card and sound level meter.
Set up recording
Recordings can be very important when post-processing measurement data to identify noise or perform detailed analysis such as FFT-based pitch evaluation. If your sound level meter supports recording, be sure to set it up to measure at the correct resolution and sample rate for your needs. It is worth noting that audio recorded with automatic gain cannot be used for subsequent analysis.
Set frequency weighting and bandwidth for frequency analysis
It is best to ensure that the correct frequency weighting and bandwidth are measured for frequency analysis. While common practice is to post-weight the spectrum, or combine 1/3 octave bands into 1/1 octave bands, both have potential drawbacks. Post-weighting can produce significant errors when there are strong tones far away from the center frequency. While summing 1/3 octave bands works for Leq data, it doesn't work for many other parameters, like statistics or even Lmax or Lmin.
Turn extended low frequencies on or off
Making measurements using an extended low-frequency range can increase the impact of wind-induced noise on measurements, especially those using Z-frequency weighting. Therefore, only extended low frequencies are included when very low frequency noise is relevant.
