Narrower frequency bands make audio signals less correlated and easier to quantize

Evidence

The narrower the bands are, the more effective this concentration can be. The used and unused band information needs to be transmitted to the decoder and therefore represent additional side information to be encoded and transmitted to the decoder. The signal within the bands is also less correlated because, as the band gets narrower in frequency range, the spectrum within the band is more likely to be uniform and thus approaches the desired white-noise spectrum with zero correlation between samples. A further advantage of frequency domain processing is that it converts the audio signal into a form that makes it easy for psychoacoustic quantization to be efficiently applied. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2607

Categorization

• DEFINE: Explains why narrower bands approach white-noise spectra with zero sample correlation — core to perceptual coding.