Here’s a quote from Paul McGowan, the owner and senior desiger at PS Audio, that he posted the other day on his daily blog. “PCM is on its way out. The very language that started the digital audio resolution is going the way of Esperanto.” As you might expect, I was surprised to learn this and actually wrote a quick response to his comment during my office hour yesterday at the university. My comment was about the realities of the professional production facilities and the standard practice of audio engineers making the audio played back through digital to analog converters. We’re ALL working in PCM.
Paul responded, “Boy, then you’ll love tomorrow’s post. I agree with you in part – as I will mention in tomorrow’s post, PCM is the majority carrier of music and storage of that music, editing and manipulation and will be for some time to come – having said that, most of us are converting from PCM to DSD in our DACS (and not knowing that).
That notwithstanding, I believe the future of all digital REPRODUCTION will be via DSD based Delta Sigma DACS. Storage will be via PCM as you suggest.”
Okay, so Paul acknowledges that the audio world is going to stay with PCM for the production of new recordings. He’s right. That’s where the tools are and that’s what the production world knows. But we’re going to be converting the PCM digital audio back to analog using DACs that have a Delta Sigma processing stage in them. He calls this “DSD based”. Most engineers wouldn’t…they’re still PCM DACs.
I have to wonder about whom the “most of us” that Paul is talking about in the second paragraph. Is he referring to the equipment designers that are including DSD in their “new and improved” DACs? These are guys like John Siau of Benchmark and Mike Moffat, formerly of Theta Digital. Both of these very experienced designers know the shortcomings of DSD and have publicly expressed their opinions on the topic. But there companies have actually included DSD conversion in their latest designs. However, if you ask them why they did it, they will tell you because there is money to be made from consumers that perceive DSD as being superior to PCM. Give the customers what they want…and they did. That statement may be true for those consumers that like SACDs but it is not universally true. I’ve gotten lots of email from consumers that have heard SACDs for years and still prefer PCM.
Then again, Paul might be saying that because modern DACs now include advanced integrated circuits that have some sort of multi-bit, very high sampling rate, Delta Sigma stage (not officially DSD, which remember is limited to 1-bit) prior to the decimation back to usable output of PCM audio 24-bits long…that DSD is taking over the world of high-end audio. That’s like saying that because there is a battery in all automobiles that electricity is overtaking gasoline-operated cars. Come on.
I’m not an equipment designer. I know enough about electronics and digital theory to be dangerous but I don’t pretend to be able to speak with authority on the intricacies of the latest converter chips. However, I can read a schematic, repair most analog electronics and I do understand when someone is speaking out of the corner of his or her mouth.
PCM is most definitely not on the way out…as Paul acknowledges in his response. He said it because he knew it would generate controversy and comments on the PS Audio blog page. He’s a smart marketer.
He is an advocate of the PDM model for encoding of audio. I’m not. The facts as I have studied them simply don’t add up…but we’ve already talked about that. I won’t be using DSD to record any of my pristine recordings. I am considering doing what Benchmark and Schiit Audio have done and “give the customers what they want”. I might make DSD versions of my own stereo HD-Audio PCM masters available on iTrax.com.
What Paul is saying is that the use of a Delta Sigma component in modern DACs somehow transforms ALL audio that goes through that component (which is DSD like but definitely not DSD) into DSD. This is marketing speak and deliberately vague. And not true.
Fans of DSD get encouraged by statements like that and those of us that prefer the science and sound of PCM can accept it as marginally true as long as we know that modern DACs are still going to take PCM encoded audio in one end and put high-quality analog audio out at the other end. What goes on in the box could be a flux capacitor for all I care.
Future productions, mastering, encoding and distribution will be dominated by PCM audio for a very, very long time. Count on it.