Remember, the clipper gives only about 4 dB of headroom "expansion." Overdriving by any more than that causes you run the risk of overloading the circuitry upstream of the clipper. This is dependent on the calibration of the unit, too. You just have to watch out that you don't exceed the overall maximum input level of +27 dBu.Conclusion:First, set input levels with the clipper OFF, just to get an idea where 0 dBFS is. Then, engage the soft clip circuitry for insurance. The clipper is not intended to be a substitute for good recording practice.