How to perform “Total Calibration”?

The purpose of this type of calibration is to calibrate the whole output chain in one operation. We recommend that you instead use the Detailed Calibration (see below) if you are using WinMLS both for electrical measurements and measurements where you are using a transducer (e.g. a loudspeaker), or if you are using an amplifier with changeable gain.

If you are not already in the Input level calibration for channel 1dialog box, go there (Measurement->Hardware Calibration, click Settings… to the right of the Input calibration check box.

First make sure that the list box named Type of calibration at the top of the calibration dialog box is set to Total Calibration.

Right below, make sure that you have checked if you are using a transducer. Select in the list box the unit of the transducer you are using (for a microphone this would be Pres [Pa]).

The settings for the total calibration are shown below:

Click the button to view the Total Cal. Settings dialog box.

Type the desired signal frequency and level in the dialog box. 1000 Hz should be fine for most purposes. From here you can also set the level, and choose if you want to use an external meter or use the sound card input to measure the output level. Using the sound card input for measuring the output level is fine if you have calibrated the input.

If you are to use an external meter to measure the output level, choose Use external meter to measure level in the list box. Then measure the output level on channel 1 (left) using the external device after clicking the button. Type the measured level in the dialog box below the frequency setting (you are also asked to enter the level during the actual calibration, the level you have typed now will show as default).

If are to use the sound card input to measure the level, select Use soundcard input to measure level. The sound card input will now measure and determine the level automatically, no number to be typed, but you must be sure that the sound card input is calibrated properly and that it is connected to input channel 1 (left).

Now click the button to perform the calibration. After the calibration is performed, the number to the left and the date to the right of the Calibrate button will be updated with the new settings. Now you can do a measurement to test if the calibration is correct. You can use sinusoid as excitation signal (see How to use a sinusoidal excitation signal?). Please note that if you repeat the calibration, the number may not seem to be changed, but if the date is updated, this is probably because exactly the same number is written.

If is checked, it is assumed that you are using a transducer when doing the level calibration. Note that if this check box is turned off, no warning will be given that you should redo the calibration. If you are going to do a measurement later without using the transducer, a new calibration must be performed.