Dr. AIX's POSTS — 08 February 2014


Normally, I wouldn’t post statements made by individual producers of recordings that I’ve investigated, evaluated, tested and discussed in one of my posts…but it seems a member of Qobuz (the French download site) lifted my entire article (you can read it at here) from January 27th and posted it on a Qobuz forum. Given that the article shows a couple of downloaded tracks claiming to be high-resolution are actually misidentified as such, the site contacted the producers of the recordings for their reaction. This makes it worth re-posting their positions here.

Before I continue I feel obligated to state the following. It takes a lifetime of experience, a willingness to share my knowledge and opinions and a substantial amount of time to post a daily blog post. And although I’ve seen it done before, I’m discouraged that the Qobuz site would allow someone to “reprint” my entire article with the associated graphics on their site without my permission. I would have expected them to link to my post and add any comments locally.

The post on the French site says, “Hello, not finding your site the ideal place to post a response to the particularly sensitive issue of the quality of high-resolution files…”. That’s a cop out…they basically appropriated my post without permission. I have requested that they remove it and simply link to RealHD-Audio.com.

The Qobuz site is a French site. I know enough French to be dangerous but I did use the Google translator to read the statements from the producers of the two recordings in question. So the words are Googles translation and not the actual words of these gentlemen.

The first comes from Jean-Marc from Psalmus Records, the producer of the “Great Song to the Virgin (PSAL013). If you go back and look at the spectragram I created using Audition, you’ll clearly see that it tops out at 23 kHz. And I did acknowledge that human voices are not going to contain much information in the ultrasonic range. But this is a CD-Quality recording and definitely does not qualify for the High-Resolution name. Jean-Marc response actually confirms this.

You can go to the Qobuz site and read the translation of the responses (Here’s the link).

The essence of his message is that I’m confusing the “technically achievable sound spectrum thanks to high definition formats and the actual sound spectrum of musical instruments and voices”. There’s no confusion here…at least on my part. I know the frequency response of the human voice and instruments. But even considering those realities, why would Qobuz sell/provide a file that is only as good as a CD in a bit bucket that extends to 96 kHz (the sample rate is 192 kHz)? A more straightforward scheme would be to acknowledge that this particular recording doesn’t need the 192 kHz/24-bit sample rate and provide it at 48 kHz/24-bits. Why ask your members to download a file that has mostly zeros? And you certainly wouldn’t provide it as a demonstration of how good things can get in high-resolution.

Just so that you can view a vocal recording that isn’t rolled off…here’s a spectragram of my Zephyr: Voices Unbound project from many years ago.


Figure 1 – The spectragram of an a capella vocal track at 96 kHz/24-bits from AIX Records. There is no Low Pass Filtering and actual sound up to about 30 kHz [Click to enlarge].

This is what a real high-resolution audio track looks like…even one that contains only voices. There is no roll off suddenly at 23 kHz!

He goes on to talk about other projects with greater frequency response and then begins talking tech. And it’s apparent that Psalmus is a DSD shop that uses DXD to do their production work. Here’s the tech notes associated with the recording in question:


Figure 2 – The head of Psalmus provided the technical details associated with their Qobuz release at 192 kHz-24 bit PCM [Click to enlarge].

The technical details from Jean-Marc reveal the truth behind this recording. And it yet another example of why buyers of so-called “studio masters” or “high-resolution” audio files should do their homework. Look at the highlighted items in the list. This is DSD 64 recording, which means that it will deliver great “in band” sound up to around 25 kHz before the much-discussed ultrasonic noise becomes a factor. This is simply part of the DSD encoding scheme…and the way that people get rid of it is to use a Low Pass Filter…in this case at 23 kHz. If I were required to record a project using DSD 64, I would do the same thing. But I wouldn’t call it a high-resolution audio track.

Then what did Psalmus Records do? They used a software converter (the very good Saracon made by Weiss Engineering) to turn their DSD 64 file into a 192 kHz/32 bit PCM file. Does upconverting a “standard resolution” audio recording to 192 kHz/32-bits elevate the fidelity of the source? Absolutely not…as the spectragram clearly shows. There is nothing above 23 kHz. The fidelity of this recording is standard resolution. In our new lexicon of terminology it would be a Standard Definition Recording, High-Resolution Post Production and High-Resolution Distribution.

And maybe it doesn’t matter. The recording sounds really good. But the last line of the note from Jean-Marc says, “Can we do more natural than that?” Well as a matter of fact, you can. Here’s a few thought that come to mind:

• Avoid DSD and record in a format that will give you accurate dynamic and ultrasonic frequency response without the noise.
• Don’t put a 1-bit DSD 64 recording into a 192 kHz/32-bit PCM container…it does nothing for the fidelity of the tracks.
• Don’t make a CD-Quality recording and then market it as something that it’s not…just stay with CD fidelity and everything would be on the up and up. There’s nothing wrong with recording and releasing CDs. Your recording sound great just the way it is.
• Don’t apply a Low Pass Filter, it just means you’re trying to hide something.

I’ve written too much today. I’ll go through the response regarding the other track tomorrow.

NOTE: A co-founder of Qobuz tweeted to me and called my post “malicious”. Nothing could be further from the truth. My intent with these posts is to inform. If there’s something that I’ve said that is incorrect, I will correct it and offer my apology. So far I’ve not found anything in my post about these tracks that needs correcting.

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About Author


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.

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