A device which produces a known sound pressure on the microphone of a sound level measurement system, and is used to adjust the system to Standard specifications.
- The standard acoustic calibrator produces a pure tone of 94dB at 1kHz. This is useful in that A, B and C weighting networks give zero attenuation at 1kHz.
- A pistonphone is useful when wanting to calibrate at a larger sound pressure level, typically 124dB. However, the standard pistonphone produces a pure tone at 250Hz and so the level will be affected by the weighting networks.
- For FFT analysis a Flattop weighting and a sensible number of averages acquired to get a stable number.
- Seal that sits within the calibrator is damaged allowing an air/acoustic leak
- Microphone not fully pushed into the calibrator and so not sealed
- Pistonphone switches off during calibration
- Weighting network applied with a pistonphone
- FFT window not set to flattop