Sound Level Meters
The tests on sound level meters will be performed using the applicable standard listed in the manufacturer specifications:
- IEC 61672-3: 2013 (also adopted as US national standard ANSI S1.4-3:2014) if there is a claim of compliance with either the 2002 or the 2013 version of this standard;
- old ANSI S1.4:1983 & ANSI S1.43:1997 if there is no claim of compliance with the IEC 61672 standard.
Tests according to the old IEC 651/IEC 804 are still available upon request.
With the recommended Standard Calibration Service, the sound level meter is thoroughly tested by:
- Using electrical signals to check the characteristics indicated by the standards, and either
- A separate calibration of the microphone (provided for type/class 1 instruments) followed by a calculation of the global acoustical response, or
- Using acoustical signal to check the global frequency response (multi-function calibrator method), provided for type/class 2 instruments.
In addition, a global accuracy check is performed using both the laboratory reference calibrator and the recently calibrated, customer provided accompanying calibrator.
Additional functions like dose measuring are tested using acoustical signals of 94, 104, 114 and 124 dB.
If octave or third octave band filters are present in the instrument, then our standard calibration service includes partial test of the filter sets. For each set, we test the relative attenuation of the two filters with highest central frequency. Additional tests on the filters are available as a separate service (see 5 below).
With the Basic Calibration Service, the instrument is tested using acoustical signals with levels of 94, 104, 114 and 124 dB and frequencies between 31.5 Hz and 16 kHz. The main characteristics of the instruments are checked. A global accuracy check is also performed using both the laboratory reference calibrator and the recently calibrated, customer provided accompanying calibrator. Additional functions, like dose measuring, are tested using acoustical signals of 94, 104, 114 and 124 dB. Usually, the octave or third octave filters are not tested with this service.
An alternate version of this service uses electrical signals to perform some of the tests. This is not possible for any instrument.
With the Manufacturer Level Calibration Service, the response of the simple sound level meters is measured in a frequency domain from 31.5 Hz to 16 kHz while using the weighting networks present in the instrument. The tests use sine acoustical signals of 94, 104 or 114 dB. A global accuracy check is also performed using both the laboratory reference calibrator and the recently-calibrated customer-provided accompanying calibrator.
A detailed list of the tests included in each service can be found here.