This method of calibration uses a reference sound file that has a known sound pressure level (relative to the gain of the recording that is to be analysed).
This method is useful if:
- you have recorded a calibration tone that has a known sound pressure level using the same gain as the recordings you wish to analyse; or
- you have recorded a calibration tone that has a known sound pressure level using a gain that has a known difference to that of the recordings you wish to analyse.
- you have any soundfile, and you know what its equivalent sound pressure level is, with reference to the gain of the recordings that you wish to analyse.
This is the method that you may wish to use if you record with a measurement microphone with a microphone calibrator.
This method is not useful if you do not have a reference sound file.
Note - you can use the one file for calibration reference and for the analysis input. This is one way of specifying the equivalent sound pressure level of the file to be analysed. However, it may make better sense to do this using 'Calibrate without files'.
The duration of the calibration file should be at least several seconds (we recommend a minimum of 10 seconds), and should be 'clean' (i.e. it should not include silence or noise - but should just contain the calibration tone). Using a short file will introduce errors in the calibration (partly due to the 'fast' exponential temporal integration that is being used in the calibration routine, and partly because short recordings have greater succeptibility to random error).
