Dr. AIX's POSTS TECH TALK — 14 November 2015

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“Why should consumers care about Hi-Res Audio?”

This is the next FAQ in the CEA/CTA and Sound & Vision “Guide to Hi-Res Audio”. Again HRA refers exclusively to hardware and so it’s problematic to understand the answer provided by the author of the article.

He mentions the “growing” popularity of lossy compressed digital files that consumers download from iTunes and other sites. Digital music downloads are not “growing” in popularity. In fact, they are diminishing in favor of music streaming services.

I read today that Apple has suspended the Beats music download site in favor of its own Apple Music service. They were prompted to move into the streaming marketplace because Spotify and Pandora were running away with the streaming music delivery market. Music has long been a commodity to the average consumer. Consumers don’t care about Hi-Res Audio/Music, period. The guide and the rest of the advertising attached to HRA are promoting a myth as it is currently being done.

The claim in this question on the FAQ section of the guide is that consumers are “sacrificing sound quality for convenience”. What the author didn’t share was the the CEA’s own research showed that consumers can’t tell the difference between a good MP3 and real high-resolution music file. Even if the Hi-Res Audio logo is attached to the headphones or speakers. The last sentence is another one of those nebulous claims that HRA “represents an opportunity for consumers to get closer to a studio experience and hear more emotionally engaging music”. Getting the best musical experience doesn’t depend on hi-res music files played through hi-res audio equipment if the music originated as an analog reel to reel tape from 30-50 years ago.

FAQ # 4 “Do I need to be a techie to get into Hi-Res Audio?”

The simple answer is no according to the writer but he then launches into to a “quick primer” about audio waveforms and digital encoding.

“All music can be represented by a single, varying waveform that changes over time.” Amazing as it might seem, he’s right. Music of all types from orchestras to Gregorian Chant can be reduced to a single, PERIODIC, waveform (it is possible to have a varying waveform that generates no musical sound…there has to be a period or frequency associated with it).

You can read his description of “analog-to-digital” conversion for yourself. I pause whenever someone tries to tie audio and video together, which he does, “This process is similar to how a video camera captures moving images by taking individual frames.” It’s not similar…capturing a sequence of discrete, analog images like Edison did at the turn of the 20th century is very different than converting analog waveforms into strings of digital words.

When his primer delves into sampling, he states, “A CD-based system samples the waveform 44,100 times a second, while Hi-Res Audio typically measures a waveform 96,000 or even 192,000 times a second. This higher sample rate allows the faithful recording of much higher frequencies, resulting in a vastly larger audio bandwidth.”

The last sentence is problematic. It’s true that higher frequencies…the ultrasonic ones that our ears don’t respond to…can be captured using higher sampling rates and the bandwidth is higher (but only one octave, so vastly might not be the best descriptor) but the best reason for having a high sample rate is to ease the construction of the filters required during the AD and DA process.

I’m going to post the ridiculous illustration that attempts to visualize the improvements offered by applying more bits to each sample. By now, readers of this blog know that this is NOT how PCM digital sampling works. The illustration is completely wrong!

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Figure 1 – The graphic included in the FAQ section of the Guide showing the “benefits” of HRA.

There are no stair steps in PCM digital encoding. MP3 is a compressed technique and shouldn’t be included in a diagram comparing bit resolution. I never saw this diagram during the review process or I would have encouraged the board to remove it.

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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.

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