Audio normalization
Audio normalization is the process of increasing (or decreasing) the amplitude (volume) of a digital audio recording. Typically normalization increases the amplitude of the audio waveform to the maximum level without introducing any distortion into the recording.
Often times, if the internal volume is too loud, normalization causes the waveform to clip. Hard Limiting can fix this by boosting the internal level but keeping the waveform below a certain set dB.