target loudness of ReplayGain utilities is 89 dB sound pressure level. The SPL reference comes from a SMPTE recommendation used to calibrate playback levels in movie theaters. A more common means of specifying a reference level is relative to a full-scale signal. ReplayGain nominally plays at -14 dB relative to full-scale leaving 14 dB of headroom for reproduction of dynamic material. In contrast, the SMPTE RP 200:2002, on which the ReplayGain reference was originally based, recommends 20 dB of headroom. The more recent EBU R 128 suggests 23 dB. Track-gain and album-gain ReplayGain analysis can be performed on individual tracks, so that all tracks will be of equal volume on playback. Analysis can also be performed on a per-album basis. In album-gain analysis an additional peak-value and gain-value, which will be shared by the whole album, is calculated. Using the album-gain values during playback will preserve the volume differences among tracks on an album. On playback, listeners may decide if they want all tracks to sound equally loud or if they want all albums to sound equally loud with different tracks having different loudness. In album-gain mode, when album-gain data is missing, players should use track-gain data instead. Alternatives Peak amplitude is not a reliable indicator of loudness, so consequently peak normalization does not offer reliable normalization of perceived loudness. RMS normalization is more accurate, but does not take into account psychoacoustic aspects of loudness perception. With dynamic range compression, volume may be altered on-the-fly on playback producing a variable-gain normalization, as opposed to the constant gain as rendered by ReplayGain. While dynamic range compression is beneficial in keeping volume constant, it changes the artistic intent of the recording. Sound Check is a proprietary Apple Inc. technology similar in function to ReplayGain. It is available in iTunes and on the iPod. Standard measurement algorithms for broadcast loudness monitoring applications have recently been developed by the International Telecommunication Union (ITU-R BS.1770) and the European Broadcasting Union (EBU R128). Implementations Audio players AIMP, Windows, Android - can write and read Amarok, KDE desktop environment. Native ReplayGain support was added in Amarok 2.1. Audacious, Unix-like systems and Windows Aqualung Music Player, Linux and Windows Banshee, Linux Clementine, Windows, Mac OS X and Linux cmus, Unix-like systems Cue Broadcast Audio Player, Windows DeaDBeeF, Linux, *BSD, OpenSolaris and Mac OS X Exaile, Linux/GNOME desktop environment FLAC, the reference FLAC decoder can create a new copy