Noise Shaping - Noise Shaping in Digital Audio

Noise Shaping in Digital Audio

Noise shaping in audio is most commonly done as a bit-reduction scheme. The quantization error from straight dither is flat, white noise. The ear, however, is less sensitive to certain frequencies than others at low levels (see Fletcher-Munson curves). By using noise shaping we can effectively spread the quantization error around so that more of it is focused on frequencies that we can't hear as well and less of it is focused on frequencies that we can hear. The result is that where the ear is most critical the quantization error can be reduced greatly and where our ears are less sensitive the noise is much greater. This can give a perceived noise reduction of 4 bits compared to straight dither.

Read more about this topic:  Noise Shaping

Famous quotes containing the words noise and/or shaping:

    But what it was, alas, I cannot tell,
    Because of it I had no perfect view;
    But as it was, by guess, I wish it well
    And will until I see the same anew.
    Shadow, or she, or both, or choose you whither:
    Blest be the thing that brought the shadow hither.
    —Unknown. I Heard a Noise and Wishèd for a Sight (l. 13–18)

    Lovers and madmen have such seething brains,
    Such shaping fantasies, that apprehend
    More than cool reason ever comprehends.
    The lunatic, the lover, and the poet
    Are of imagination all compact.
    William Shakespeare (1564–1616)