What Hi-Fi (UK)
DSD and SACD
What is DSD? How is it different from other music files and how can you listen to it?
DSD (Direct Stream Digital) was conceived as a way of archiving old analogue recordings, it was designed to be a simpler, more space efficient way of storing digital music data.
How does DSD work?
DSD uses a single bit of information that tells us is whether the current sample of the analogue waveform is higher or lower than before. Compared with over 65,000 different values 16-bit PCM has, the two values (0 if the new sample of the signal is lower, 1 if it’s higher) of DSD appear limiting. That resolution shortfall is made up by the very high sampling rate of over 2.8 million times a second – 64x the speed of CD. Standard DSD is also called DSD64 for this reason, with double and quadruple speed versions called DSD128 and DSD256.
What are the downsides to DSD?
It’s not very practical to manipulate a DSD recording. All the things that are required postrecording – equalisation, editing, dynamic range control, adding reverb – usually involve the DSD stream being converted to PCM to do
the processing and then switched back. It’s down to a lack of suitable equipment and processing software.
How do you play DSD?
DSD playback has become far more common and most recent mid-to-high end digital playback equipment tends to be compatible; if you have something suitable there’s no reason to treat it any different from FLAC or WAV files.
Where can you buy DSD audio files?
Most of the major audiophile music sites sell DSD downloads. The likes of Hdtracks and Highresaudio are good places to start.