Super Bit Mapping (SBM) is a

noise shaping Noise shaping is a technique typically used in digital audio, image, and video processing, usually in combination with dithering, as part of the process of quantization or bit-depth reduction of a digital signal. Its purpose is to increase th ...

process, developed by

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...

for CD mastering. Sony claims that the Super Bit Mapping process converts a 20-

bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented a ...

signal from

master recording Mastering, a form of audio post production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master), the source from which all copies will be produced (via met ...

into a 16-bit signal nearly without sound quality loss, using noise shaping to improve

signal-to-noise ratio Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in d ...

over the frequency bands most acutely perceived by human hearing. Audible quantization error is reduced by

the error according to an

equal-loudness contour An equal-loudness contour is a measure of sound pressure level, over the frequency spectrum, for which a listener perceives a constant loudness when presented with pure steady tones. The unit of measurement for loudness levels is the phon and i ...

. This processing takes place in dedicated hardware inside the recording device. A similar process is used in Sony's DSD to

PCM Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the a ...

conversion and is called ''SBM Direct''.

References

Sound technology Digital signal processing {{Sound-tech-stub

See also

References