Loop-back measurement procedure

Select Measurement->Test Levels to display the dialog box showing the input and output levels. If your sound card supports the WinMLS mixer, the volume controls Sync. Out and Sync. Input will be displayed as shown to the right in the figure below. Use these sliders to set the volume for the loop-back synchronization signal.

Select Measurement->Start to start performing the measurement. An error message will be given if the loop-back volume is too low or too high. Adjust the volume accordingly.

The result of a successful measurement should now have almost the correct initial time delay. But as we have seen, the sound card has a delay of some samples, which is usually less than 1 millisecond. To subtract this delay a measurement system correction of the sound card must be performed as described in the Measurement section of the FAQ or channel 2 can be used as reference.