DSD Pure in Sonoma

Gus Skinas owns and operates the Super Audio Center in Boulder, Colorado, where he engineers various record projects and sells the Sonoma DSD audio recorder and editor. This system, which was the first multichannel DSD digital workstation, was developed by Sony and made available to a number of studios and labels as the SACD format was emerging 13 years ago. I know Gus and he’s a good engineer and believes in his products. The folks at Sony and Phillips were closely associated with Gus’ business.

I downloaded the Sonoma32.pdf electronic brochure from his site some time ago as I was studying the DSD ecosystem. This was right after I had the opportunity to use a Sonoma system at Snow Ghost Studios in Whitefish, Montana. The brochure is full of testimonials from prominent engineers singing the praises of the DSD and SACD format as well as the Sonoma DAW.

The document opens with the following:

“Nothing you can do will improve the sonic quality of your analog studio as dramatically as switching to a Sonoma DSD Multitrack Recorder-Editor with an EMM Labs front end. The Sonoma is the perfect solution for the artist who needs the power of a contemporary audio workstation but desires the sonic character and integrity of analog recording systems. The audio recording technology inside the Sonoma is fundamentally different from standard PCM digital recorders. The Sonoma records audio as a one-bit sigma-delta stream at a sample rate of approximately 2.8 million samples per second. It is the Sonoma’s ability to capture extraordinary detail in the time domain that sets it far apart from conventional digital PCM recorders of any sample rate.”

Recognizing that the pdf file is a sales piece, I understand the hyperbole that the author of the brochure uses in this and subsequent passages. And fine, if you’re a studio owner and someone wants, “the sonic character and integrity of analog recording systems”, then having an analog tape machine or a Sonoma system might make sense. Brett Allen at Snow Ghost studios has both AND a fully tweaked out HD-Audio PCM Pro Tools systems. BTW There are lots of “make my PCM digital audio sound like an analog tape machine plug-ins out there…so a Sonoma system or analog tape machine are really not required).

HD-Audio in PCM format lacks integrity?

How about DSD integrity? Did you know that the DACs in the early SACD player from Sony and Phillips converted the DSD 2.8224 MHz 1-bit signal to a multibit (usually 3-5 bits wide) PCM signal so that the required low-pass filtering could be done in the digital domain? This is according to the Sony/Phillips technical documents. The reason given was because the analog filtering didn’t meet high-end audio performance. So the output of every early Sony/Phillips SACD player went through a PCM stage.

Getting back to the Sonoma DSD system brochure. They brag about various aspects of the system and bring special focus to the “Unparalleled Editing Power” that the system includes. Remember that the DSD 1-bit world doesn’t allow for fades or processing without moving to the PCM format. Simple edits are available on the Sonoma system but when it comes to doing crossfades, the most common type of editing used in most workstations, DSD Pure is required.

DSD Pure is described in a side bar. To quote a part of the section:

“The Sonoma recorder/editor keeps the audio at the DSD sample rate of 2.8 million samples per second at all times. When edits are made, the audio is crossfaded in real time using special signal processing at the same DSD sample rate. Real time level manipulation and audio layering inside the Sonoma work the same way. The Sonoma never down-samples to a lower sample rate for signal processing, so the time domain integrity is maintained.”

Here’s the essential message in that statement. The Sonoma system never strays from the 2.8224 MHz sample rate and if you simply record and playback a DSD recording through their recommended DACS, the 1-bit digital words are maintained. However, if you want to make any edits using crossfades or do real time level changes or audio layering in system, they have to increase the bit count for each word…making the DSD into PCM once again. This is the “special signal processing” that is referred to in the paragraph. This detail is conveniently omitted from the side bar.

Who’s lacking a little integrity now?

I’m sticking with high definition PCM in my studio. And I don’t see any of my fellow studio owner friends opting for Sonoma or DSD either.