Replay Gain - A Proposed Standard

Outline

Basic Steps

  1. Calculate the perceived loudness of each track
  2. Convert this to a suggested replay gain adjustment
  3. Store this value within the header of the audio file
  4. The player adjusts the volume of each track accordingly

Comments

The Replay Gain represents a suggested gain adjustment for each track. Players can scale the audio data by this replay gain in order to achieve a consistent perceived loudness across all tracks.

The reference gain is 83dB SPL, as defined in the SMPTE RP 200 standard. If the Replay Gain for a given track is -12dB, this means that the track is relatively loud, and the gain should be reduced by 12dB, ideally to 71dB. Players which understand the Replay Gain standard will do this automatically.

Steps 1-3 can be carried out automatically, as described on this site. Alternatively, a human listener (e.g. the record producer or mastering engineer) may specify the ideal replay gain, and this value can be stored instead.