DSD64 (Direct Stream Digital, 2.8224 MHz)

Direct Stream Digital at 2.8224 MHz — the Super Audio CD (SACD) format from 1999. Encodes audio as a 1-bit-per-sample sigma-delta bit stream at 64× the CD sample rate (44.1 × 64 = 2.8224 MHz).

Different mathematical model from PCM: instead of multi-bit amplitude samples at coarser time intervals, DSD uses single-bit samples at ultra-fine time intervals, with the noise pushed via noise-shaping above the audible band. Audible result is often described as more ‘analog-like’ than equivalent PCM, though objective measurements show similar audible performance.

For higher DSD rates see DSD128 and DSD256. For native DSD playback the source must support the format end-to-end.