Loudness War - Dynamic Range Reduction

Dynamic Range Reduction

The practice of increasing music releases' loudness to match competing releases can have two effects. Since there is a maximum loudness level available to recording (as opposed to playback, in which the loudness is limited by the playback speakers and amplifiers), boosting the overall loudness of a song or track eventually creates a piece that is maximally and uniformly loud from beginning to end. This creates music with a small dynamic range (i.e., little difference between loud and quiet sections), rendering it fatiguing and robbing it of emotional power.

Digital media cannot output signals higher than digital full scale (0 dBFS), so whenever the peak of a signal is pushed past this point, it results in the wave form becoming clipped. If clipping occurs in a recording, it makes the recording sound distorted.

In other cases, compression or limiting is used. While the resulting distortion is less obvious in the final product, when taken to severe levels, it can reduce the natural dynamics of other instruments within the recording and introduce other undesirable effects such as audible compression pumping.

Dynamic range or broadcast-style compression may be applied to the music to make the loudness in different song sections more uniform. This can make the recording more suitable for background listening or noisy environments but can also reduce the dynamic expressiveness of the song as a whole. Applied in the extreme, however, very aggressive compression or automatic gain control can cause "pumping" and "breathing" artifacts as the gain changes rapidly. In FM stereo broadcasting, so-called composite clippers have also been employed that provide a hard limit to the FM stereo composite signal.