What is DsD Audio?

It looks like the DSD format is coming back into fashion. Most new digital devices support it, and the catalog of available albums inspires respect - especially for jazz and classical lovers.

What is DSD Audio?

What is it and how is it different from other digital signal recording systems used in CDs and other Hi-Res audio formats? Let's find out.

Digital streams are recorded as a combination of two states, 0 and 1; but in order for this information to be useful, it must be organized in a special way. In almost all cases, a system called PCM (Pulse Code Modulation) is used.

Let's first take a look at exactly how PCM works.

With PCM, the original analog audio waveform is described using two parameters. The first is magnitude. It is presented on CD in 16-bit digital data, which makes it possible to set 65,536 different signal levels.

To adequately represent the original waveform, it must be measured at precisely metered regular intervals. These counts are performed 44,100 times per second. The number looks random, but the choice was very thoughtful - it provides coverage of the full range of human-audible frequencies (20 Hz to 20 kHz).

DSD Audio and SACD

DSD (Direct Stream Digital) technology takes a different approach. It was developed in the mid-'90s as a way to archive old analog recordings.

It was intended to be a simpler and more memory-efficient way of storing digital music data than PCM. Most importantly, DSD was also designed from the ground up to be convertible to PCM files with a sampling rate of 44.1 kHz.

Around the same time, Sony and Philips were working on replacing the CD, which eventually took the form of SACD. The DSD system seemed to be the ideal basis for the creation of a new format - in particular, due to its excellent copy protection.

The main advantage of DSD was its simplicity and the resulting low cost of implementation. This technology required less processing than PCM, making it possible to use simpler and much less expensive DACs.

DSD uses one bit of information, which says only whether more or less the previous fragment of the analog signal turns out to be current. Compared to 65 thousand different values ​​that the PCM signal can accept, only two (0 if the signal level of the new sample is lower, and 1 if it is higher) for the DSD signal seem to be categorically insufficient to convey the necessary information.

However, the lack of information is compensated by a very high sampling rate - more than 2.8 million times per second, which is 64 times higher than the corresponding parameter for CD. Because of this, the standard definition DSD format is often referred to as DSD64, and its double and quadruple sample rate versions are often referred to as DSD128 and DSD256, respectively. There is even the DSD512 specification, although we have never heard of any material recorded using it.

Recordings in standard DSD format are still quite rare compared to alternatives in PCM, and higher-resolution recordings are much less common. However, DSD aficionados claim that this format provides the closest possible analog sound experience.

If one could see a digital stream of DSD format, it would be possible to draw the corresponding analog signal simply by looking at the distribution of zeros and ones. The more zeros, the less its value; the more units, the more it is. If the two values ​​are approximately equal, the signal level is close to zero.

This is all great, but the DSD format has its downsides. In particular, it is difficult to work with records.

Any processing on a recording — such as EQ, editing, dynamic range control, and adding reverb — usually requires converting DSD to PCM, performing the necessary conversions, and then converting back to DSD. What is DSD Audio?

This method can hardly be called simple and straightforward, but it is used for almost every studio recording made using DSD technology. It's all about the lack of suitable hardware and software.

The description of the disc may contain the notation DXD. This means that the original DSD signal has been converted to PCM with 24 bit / 352 kHz parameters and processed as such. While the name, whether intentionally or not, sounds similar to DSD, it is essentially just a very high-resolution PCM.

In addition, the analog signal derived from DSD has a high noise level compared to PCM. Sophisticated technologies enable engineers to push these noises out of the audible frequency range and optimize sound quality and speaker scale across the audible spectrum. High-frequency noise is usually filtered out.

Is DSD a Hi-Res Audio?

How high is the resolution of the DSD recordings? The relationship between PCM and DSD cannot be pinpointed, but the base format is roughly the same as PCM with 24-bit / 88.2 kHz sampling.

DSD declared dynamic range is about 120dB within audible range. For comparison, for regular CDs, it is 96 dB, and the theoretical maximum of 24/192 recordings reaches 144 dB.

Large numbers look impressive, but in fact, even the CD range is more than enough for any recording.

How do I play DSD Audio files?

In recent years, digital components have increasingly supported DSD playback; this is due to the increased availability of downloadable audio recordings. Check if your portable music player, network player, and/or DAC supports this format.

Most modern mid-range and high-end digital devices tend to have this support; if your components are one of them, be sure to add this format to the already familiar FLAC and WAV. Some flagship smartphones are also DSD compatible. And even Apple iPhone users can play DSD files with additional hardware.

On sites for downloading music from time to time, you can find the designations DSF and DFF. These are two flavors of DSD files; all you really need to know about them is always choose the DSF version if your player supports it, as it works better with metadata (such as artist name, song title, album art, and the like).

Where can I buy DSD audio files?

Most of the major audiophile sites offer the option of purchasing DSD files for download. You can start with sources such as HDtracks, Highresaudio, and Primephonic.

If you prefer physical formats and own a compatible player, SACD can be found almost everywhere.