Super Bit Mapping

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Super Bit Mapping (SBM) logo.

Super Bit Mapping (SBM) is a noise shaping process, developed by Sony for CD mastering.[1]

Sony claims that the Super Bit Mapping process converts a 20-bit signal from master recording into a 16-bit signal nearly without sound quality loss, using noise shaping to improve signal to noise ratio over the frequency bands most acutely perceived by human hearing.[2]

Audible quantization error is reduced by noise shaping the error according to an equal-loudness contour.[3]

This processing takes place in dedicated hardware inside the recording device. A similar process is used in Sony's DSD to PCM conversion and is called SBM Direct.

See also[edit]


  1. ^ Maes, Jan; Vercammen, Marc; Baert, Luc (2001). Digital audio technology: a guide to CD, MiniDisc, SACD, DVD(A), MP3 and DAT (4th ed.). Focal Press. pp. 60–63. ISBN 978-0-240-51654-7.
  2. ^ "Super Bit Mapping Technical Overview" (PDF). Sony. Retrieved 15 January 2013.
  3. ^ US 5204677, "Quantizing error reducer for audio signal"