This tutorial is for everyone working on the design or production of digital audio and should benefit beginners and experts. We aim to bring this topic to life with several interesting audio demonstrations, and up to date with new insights and some surprising results that may reshape pre-conceptions of high resolution. In a recent paper, we stressed that transparency (high-resolution audio fidelity) depends on the preservation of micro-sounds – those small details that are easily lost to quantization errors, but which can be perfectly preserved by using the right dither. It is often asked: ‘Why should I add noise to my recording?’ or, ‘How can adding noise make things clearer?’ This tutorial gives a tour through these questions and presents a call to action: dither should not be looked on as an added noise, but an essential lubricant to preserves naturalness.
Tutorial topics include: fundamentals of dithering; analysis using histograms and synchronous averaging; what happens if undithered quantizers are cascaded?; ‘washboard distortion’; noise-shaping; additive and subtractive dither; time-domain effects; inside A/D and D/A converters; the perilous world of modern signal chains (including studio workflow and DSP in fixed and floating-point processors) and, finally, audibility analysis.
