Dr. AIX's POSTS — 01 January 2015


It’s really cold in Southern California today. In fact, the temperature at LAX set a record low this morning of 36 degrees besting the previous record by 2 degrees. For Los Angeles, this is really cold and my furnace has been on constantly for a couple of days…that never happens. On our morning walk this morning, Charlie (the 10 month old Waldrep border collie) and I watched the sun come up over Santa Monica as we made our way along the ocean bluff. It’s always quiet and calm at that hour of the morning. Charlie knows I carry a tennis ball in my pocket and once we arrive at the bluff, he hunches down and insists that I pull it out and throw it. He’s a maniac for chasing the ball or his favorite activity, catching a flying Frisbee. As long as I toss the Frisbee reasonably flat and straight, he nails it pretty much every time and he never gets bored of doing it.

Given the special nature of this day…the first day of a new year…it’s only natural to make some New Years resolutions. In the spirit of continuing to push for real high-resolution audio, here’s the first item on my list of HRA resolutions for 2015:

1. It’s time to cease upconverting digital audio files. Whatever the original recorded format and specification should be respected and made available to customers. If a particular recording was made using standard resolution PCM digital equipment running at 44.1 kHz/16-bits, then acknowledge that fact and release it without modification. What possible benefit comes from converting a CD specification file up to 192 kHz/24-bits? The fidelity of the original recording didn’t improve…the noise floor is still 93 dB below any potential peak.


Figure 1 – The Linn posting about the free downloads. Notice they do carefully word the announcement by saying the “best available” versions…not real HD-Audio.

I download the Linn Christmas album in three versions: 192, 96, and 44.1 kHz and 24/16-bit word lengths. They were giving it away free. I opened the first tune in Adobe Audition to take a look at the spectra and dynamics. Take a look at what I found in the figure below:


Figure 2 – The spectrogram of Linn Records “Almost Like Being In Love” at 192 kHz/32-bit, 96 kHz/24-bits, and 44.1 kHz/16-bits. [Click to enlarge]

I’ve divided the left hand portion of the plot into three sections and labeled them according to their specifications. Can you tell any difference? You shouldn’t be able to…because this is a native CD specification recording that we upconverted to 96 and 192 kHz. The red/purplish are, which shows the top of the frequencies, stops abruptly at 22 kHz (the Nyquist frequency of a CD). Looking at the frequency vs. amplitude graph on the right side of the plot, you can clearly see that there is nothing above 22 kHz but empty air. The only noticeable aspect is that the red line…the 192 kHz/32-bit version…is slightly louder than the other two lines. Linn increased (or decreased) the amplitude of the 192 PCM version.

One of my resolutions for 2015, is to identify upconverted “high-resolution” files whenever I encounter them AND to write to the company that issued them and ask them why this occurred. I will write to Linn Records and inquire in the present case. According to a reader that has done the same analysis, 8 tracks from the album are limited to CD quality. Linn should sell them as CD resolution tracks and avoid upconverting them to 96 or 192 kHz.

They are not alone in doing this. My plan for the HRADB.com site is to identify tracks that are upconversions and include them in the database.

More tomorrow. Enjoy the start of your new year!


I’m still looking to raise the $3700 needed to fund a booth at the 2015 International CES. I’ve received some very generous contributions but still need to raise additional funds (Thanks to you readers, I’m almost there!). Please consider contributing any amount. I write these posts everyday in the hopes that readers will benefit from my network, knowledge and experience. I hope you consider them worth a few dollars. You can get additional information at my post of December 2, 2014. Thanks.

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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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