The soundcard is measured with an external loopback connected to allow its frequency response to be determined and saved as a calibration file. This response is subtracted when subsequent measurements are made, eliminating the soundcard's own response. The loopback connection goes from the output channel that will be used for measurement (usually the Right channel of the Line output) to the input channel that will be used (usually the Right channel of the line input).

Please connect the loopback now and press Next when it has been connected or Cancel to quit.