In order to determine clipping, you will need to look at the waveform of the audio signal. If the waveform is flat at the top or bottom, this is an indication that the signal is being clipped. Clipping can occur for a number of reasons, including overloading the input of a piece of audio equipment, or using an incorrect setting on an equalizer. If you suspect that your audio signal is being clipped, you can try adjusting the level of the signal, or using a different piece of equipment.