After reviewing the technical and business history of Sony’s 1-bit PCM or DSD 64 format, it’s possible to describe the “best practices” associated with the format. And what is best for one type of music and production flow might vary as we contemplate other types of music and methods of recording. Each individual engineer, producer, and label has to sort that out for themselves, but they can’t deny the essential facts of the DSD format…although plenty try.
The original intended use of DSD 64 was for the archiving of the vast catalog of Sony Music. The engineers behind the Delta Sigma conversion technique never imagined that their innovation would find its way into the consumer realm as a delivery format. And remember the archives that they wanted to preserve are all analog tapes…not new high-resolution masters. This means that the fidelity “box” associated with DSD 64 (which turns out to be about 110 dB from 20-23 kHz) only has to be larger than analog tape…and third generation analog tapes at that. CDs can do that and DSD 64 can do that as well. I have no argument with the original use of the DSD 64 format. It’s an ideal archiving format for existing analog tapes. As far as I’m concerned it’s not high-resolution or high-definition but in the specialized case of archiving analog masters it doesn’t have to be. The preceding method is “pure DSD”.
A second methodology can be described as a real time analog mixdown to DSD 64. In the specialized world of classical and jazz record production, this method can work very well. There are at least a couple of companies that I’m aware of that have chosen to make recordings of live musicians (all playing and singing during a single pass) through an analog mixing console to a DSD 64 recorder or PCM high-resolution deck. Channel Classics and Bill Schnee’s Bravura Records both work this way (although I believe Bill avoids DSD and captures to high-resolution PCM).
During the Snow Ghost sessions that I was part of in Montana a few of years ago, we recorded Wayne Horvitz’s trio using this method as well. The microphones were sent through a big SSL Series 9000 analog console, eq’d, balanced, panned and adjusted during the live performance, and the stereo output bus recorded using DSD 64 (as well as analog tape and 96 kHz/24-bit PCM). It is critical that a “final master” sound is output from the analog mixing desk because you can’t go back and adjust levels, panning, reverb, or anything else after the fact. Simple edits are possible but nothing else. This method simply can’t work in most commercial recording situations. The result is a 99% pure DSD recording.
Both of the above methods maximize the sound quality of DSD 64. At that rate the specs are only slightly better than compact discs but if you prefer the “sound” of DSD, then fine. If you raise the rate to DSD 128 or even 256 the problems of excessive ultrasonic noise that can damage your electronics (amplifiers and other processors don’t like to get large amounts of ultrasonic frequencies at their inputs) goes away or is filtered out. Recording made using either of the previous methods can be spectacular but the limitations of these schemes make them very impractical. I know Michael Bishop makes his recordings using quad DSD. I’ve exchanged a couple of emails with him about doing an interview for a future post.
The final technique and the most common is to “cheat” and use very high sampling rate PCM to do all of the production work that can’t be done in native DSD. Some engineers do their recording at 352.8 kHz 24-bit PCM (deceptively called DXD to avoid any association with PCM), do all of their post production in PCM/DXD, and simply downconvert to whatever flavor they make available to their customers. I know Morten Lindberg at 2L does things this way. He prefers the sound of high rate PCM/DXD over DSD.
According to the guys at Grimm Audio, the best release format would be a PCM recording at 88.2, 176.4, 96, 192, 352.8, or 384 kHz and 24-bits…just like the source recording. In other words, don’t do any conversions. Converting to 1-bit at 128 or 256 would be second best with DSD 1fs or DSD 64 the last best option…the standard for SA-CD. While I disagree, they relegate Redbook CDs as the least desirable format to convert to. In reality, a well-done CD captures virtually everything that a DSD 64 can.
So there you have it…the unvarnished truth behind the DSD format. I’m not quite finished though. Tomorrow, I’ll explore the varied world of alternative production techniques and DSD delivery. It’s all about maintaining the myth…and maximizing money.