Dr. AIX's POSTS — 19 July 2013

By

After a reader pointed me to the SA-CD.net site and highlighted the filtered list labeled “Original DSD/DXD Recordings”, I knew I had to come back and talk about DXD further. If you’ve been reading along, you know that only a small number of SACD releases (less than 16%) are actually untouched by PCM (if that matters). But the whole category of DXD is worthy of a closer look.

DXD stands for Digital eXtreme Definition and is one of the systems (we’ll look at another tomorrow) that have been developed to get past the lack of production tools for the DSD format.

According to the developers at Merging Technologies, their Pyramix Digital Audio Workstation is the solution. Here’s a blurb from their website.

For those who want to work in the DSD domain at 2.82MHz sampling rate for SACD production, Merging Technologies has a unique answer:

Pyramix is one of the only systems in the world to offer multi-track record/editing and mixing as well as mastering while maintaining all the real-time audio processing including of FX such as EQ, Dynamics, Reverb and Surround Sound in a DSD compatible quality level up to the final SACD master. Quite simply, to have only a mastering capability for DSD is not enough. Unless you can record, edit and process the signals in a true multi-track configuration, mastering makes little sense.

Pyramix is the first system with enough processing power and resolution to handle in real time a complete digital mixing console capable of operating in 32 bit floating point at 352.8 kHz, which is the minimum requirement to preserve all the intrinsic original quality of 1 bit 2.8MHz DSD signals.

With real-time EQ, Dynamics, Reverb etc, and with full SACD scarlet book specification for mastering, we can truly state that “Pyramix is the only commercially available system on the market that is capable of a complete multi-track source to master project for Super Audio CD production.”

I think what they’ve stated is essentially true…and is somewhat surprising for a marketing piece. Here’s the sentence that is true:

Quite simply, to have only a mastering capability for DSD is not enough. Unless you can record, edit and process the signals in a true multi-track configuration, mastering makes little sense.

The process of engineering records requires the production team to have the ability to record, edit, process (reverberation, EQ, filtering etc.) and master the audio in the multi-channel format. The Merging Technologies site makes the point where some other DSD providers do not.

So what to do? They decided to develop a digital audio workstation with a lot of tracks and the ability to process them prior to the final mastering step. And the system that they developed is all about PCM at a very high sample rate (a multiple of 44.1 kHz…or 352.8 kHz) and using 24-bit words.

Let’s be completely clear what they’ve done. Producers that want to record and release SACD or DSD downloads using the Pyramix option MUST convert the source audio to PCM, which is the format that the folks at Sony/Phillips were railing against back in 2000 when they proposed the SACD format. It’s not a coincidence that their format is called DXD instead of PCM. Calling it what it actually is might take away from the “buzz” that is currently making its way through the forums and magazines. It’s simple DXD is PCM!

Here’s the part of the quoted piece that’s open for debate:

Pyramix is the first system with enough processing power and resolution to handle in real time a complete digital mixing console capable of operating in 32 bit floating point at 352.8 kHz, which is the minimum requirement to preserve all the intrinsic original quality of 1 bit 2.8MHz DSD signals.

They’re saying that you need 352.8 kHz and 24-bit words in PCM format to “preserve all the intrinsic original quality of 1-bit 2.8Mhz DSD signals.” This gets back to the subjective side of the audio fidelity equation.

The technical/science side of the issue begs to differ. If a production team uses DSD 64 to record, the frequency response (before the noise begins to mount up) extends to perhaps 30-35 kHz. Do we really want to capture and process all of the “purple haze that exists about the “audio band”? The dynamic range might equal 20-21 bits or about 124 dB. PCM at 96 kHz/24-bits can easily encompass this level of “intrinsic original fidelity”.

So the SA-CD.net site should remove the DXD discs from the “Original DSD/DXD” category. Anything recorded using DXD belongs in the PCM column.

To be continued…

Forward this post to a friend and help us spread the word about HD-Audio Forward this post to a friend and help us spread the word about HD-Audio

Share

About Author

Dr. AIX

Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

(0) Readers Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>