Comment 3 for bug 1482163

Please note: the xFaderCalibration depends on the value of xFaderCurve to achieve a desired curve.

Fading:
xFaderCalibration 0.5 / 0
xFaderCurve = 1 / 0
Scratching:
xFaderCalibration 0.999307 / 0.998614
xFaderCurve = 1000 / 1

See:
https://github.com/mixxxdj/mixxx/blob/d46433b0ae51edf2ca7529b0889691dd54f2bb90/src/engine/enginexfader.cpp#L10

xFaderCalibration = pow(0.5, 1.0 / xFaderCurve);