Quantization error manifests as audible noise, which dither is used to randomize

Evidence

Although the quantizer will pick the output level that causes minimum error, there will on average always be some error. This error adds noise and distortion to the signal and is often referred to as quantization noise. Ideally this noise should be random, and often dither is added to ensure this. The effect of the error is to reduce the signal-to-noise ratio of the audio signal. If a binary word of Nbits bits is used to encode the audio signal, then the maximum signal-to-noise ratio is given by: Quantizer FIGURE 7. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2654

Categorization

• DEFINE: Defines quantization noise and dither, both central to the reader’s psycho-acoustics goal.
• QUESTION: What threshold of quantization noise becomes perceptible? This links directly to psychoacoustic masking limits.