Calibrating the Recording

Calibration consists of setting the parameters of the recorder (for instance the audio sound card or the acquisition chain) according to a known reference level in dB SPL.

Note: Before recording, you must calibrate the recording devices and check the recording path.
Note: Calibrating the recording device allows you to acquire a signal in its physical units (Pa for acoustics) during the recording. For example, you may calibrate a microphone using a sound level calibrator. The calibration is usually done once when using the same recording devices and the same recording chain during the recording.

Technically speaking, you will configure the conversion factor between digital unit (dimensionless unit of the digital signal to be recorded) and physical unit. For example, you may use Pascal as a physical unit for acoustic signal. The calibration depends on the amplification setting of the acquisition chain. It also depends on the hardware (sound card, microphone ...).

To Calibrate the Recording:

You need to open the Recording window. You need acquisition devices, including at least a microphone and a sound level calibrator.

  1. Install and configure the acquisition device.

  2. Select the recording device in the list.

  3. Record the reference signal emitted by the sound level calibrator for few seconds.

    A reference signal is the signal recorded when using a sound level calibrator, for example a sine at 1 kHz, 94 dB SPL.

  4. Click the recorded signal window.

  5. Click Tools > Signal settings.

  6. Click Auto in the Signal settings dialog box then choose Set level.

  7. In the Level (dB) dialog box, type the level in dB SPL of the sound level calibrator then click OK.

    The calibration value is displayed in the Calibration box of the Level dialog box.

  8. Copy the calibration value in the Calibration box of the Recording window then proceed to the sound recording.

The recording calibration is complete.