If you hear clipping:
Find out if you are clipping on the input or just on the output - use a rimshot and watch the input gain on your interface and the input monitor in Sensory Percussion. If you are peaking on either meter, turn the input gain all the way down on your interface. If it is already all the way down, add a pad to the channel before readjusting the volume. See Checking for Signal in Sensory Percussion.
If you are not peaking on the input, but hear clipping on the output, first check to make sure that the sample/s you are activating were recorded at the correct level. If the samples were indeed recorded without clipping, consider removing some normalizations from your sample-stack, removing gain from one or more samples, or adding a compressor with a high ratio and slow release on the main fader or clipping track. In some cases you can use a clipper to soften the harshness of clipping sounds.