What is DSD?
DSD means Direct Stream Digital. It’s a high-resolution audio signal that is processed in a different way compared to PCM (Pulse Code Modulation) as used in audio CDs.
Instead of using many bits and a number of sampling rates as used in audio CD for example 16 bits and 44.1kHz, DSD uses a single bit.
However, this single bit is sampled 2.8 million times every second to produce a high-quality audio signal.
The usual process is audio with a high bitrate and sampling rate is modified by a DAC (Digital to Analog Converter) to the desired bitrate and sampling rate.
For example, a ‘raw’ 24 bit 96kHz audio file can be converted to audio CD’s 16 bit 44.1kHz through this method.
DSD Advantage : Downloadable Digital Formats
The overriding advantage of DSD is that it can be delivered in the following digital audio formats – FLAC, ALAC, WAV, or AIFF as will be explained below.
DSD is used in SACD (Super Audio CD) which Sony and Philips developed in the 1990s in the hope of replacing the audio CD.
This didn’t happen but DSD has come back to stake a claim in the digital audio world by reincarnating itself as a downloadable digital audio format available via streaming and USB playback.
For example at a site called hdtracks.com Michael Jackson’s Thriller album is available as a DSD 2.8MHz download for USD24.99 alongside other high-definition music formats like FLAC, ALAC, WAV, and AIFF.
Such services allow you to download audio files with the .dsf extension to be played back through your DAC system.
What is PCM? Is DSD Better than PCM?
PCM (Pulse Code Modulation) is the method through which sampled analog audio signals are digitally represented.
It’s popularly used in computer audio, CDs, digital telephony systems, and various other digital audio applications.
It is also used in Sony Digital8 camcorders.
PCM can’t be said to be an inferior audio format. It’s actually an uncompressed and lossless format, chiefly used as source data for creating other types of audio formats.
Learn more about the PCM audio format.
DSD Encoding Technology
DSD, on the other hand, uses an encoding technology called Pulse Density Modulation.
An audio signal is stored in single bits but at a sampling rate of 2.8224 MHz. That is 64 times the sampling rate of an audio CD (44.1 kHz).
DSD’s quality is around PCM’s 24-bit/88.2kHz.
But in relation to the PCM quality of audio CD (16-bit/44.1 kHz) DSD is superior.
So, is DSD better than PCM? On paper, yes.
Still, most folks prefer audio CDs over high-definition audio formats as the ear can hardly tell the quality difference between the two or they simply don’t have the high-tech equipment to process high-definition audio signals.
As for the rest of us who are always on the go with our mobile devices always at hand, MP3 is sufficient to fulfill our music needs.