Dynamic range compression (DNR) is used for several purposes. One reason (perhaps the major one) is to reduce the impact of background noise on audio signals. Another reason is to reduce the surprise effect of sudden loud sounds, while yet another is to normalise the signal level of a transmitted signal. Such normalisation may be useful for processes such as speech recognition, where a speech recognition process may work better with normalised signal levels. Dynamic range compression may also increase the apparent loudness of an audio source, and some broadcasters like to do this as it feels that it gives them a greater presence and competitive advantage.