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!

151114_stairsteps_image

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.

(15) Readers Comments

  1. You are completely accurate about streaming. A new Italian restaurant opened in town. High on a wall in one corner of each room (there are three) is a Sonos speaker, controlled by remote from the Chef’s section. The same Sonos speaker I received an email ad from Pandora about recently. It was streaming Pandora radio. A sign of the times indeed unfortunately. And on it were 70’s classic tunes like Hotel California etc. Hardly state-of-the-art sounding, but better than my LPs, cassettes, and car radio. And the public couldn’t care less.

  2. Wow. This “guide” just sounds like so much industry sponsored pablum! Please keep fighting the good fight Mark. For whatever it’s worth, we all appreciate your efforts!

    • Carlo, it very unfortunate that the people and organizations behind the guide chose to ignore suggestions to get it right and then chose to remove me from their midst. They’ll realize at some point how wrong they were…or perhaps not.

  3. Hi Mark,

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

    Well, there’s certainly no obligation for consumers to care for high resolution audio, but consumers SHOULD VERY MUCH care about large organizations representing large corporations and business interests, being able to lie to them, to advertise pretty much whatever they want, and act as authorities regarding technical and scientific facts or content, while deliberately misrepresenting scientific facts and content that is part of what we currently learn in school and as professionals.

    This should definitively be if not a chapter, at least a pertinent annex in your upcoming Audio Guide.

    There’s on the one hand, false advertisement, false claims and blatant lies deliberately made in the attempt to make profit. But on the other hand, there’s misrepresentation of scientific facts, digital technology and engineering. Not only should consumers be offended, but also the science and the professionals whose work is being distorted and misrepresented.

    I do believe that there can be a serious backlash to these advertising campaigns in other places where regulations do apply and people really care, like in European countries, where consumers have a lot more power than in the US.

    I think that this is most certainly a topic your book shouldn’t exclude, and very much be a first step in the direction of denouncing this fraud and bad practices as such, as well as the CTA and other organizations who are responsible for the hoax. The book could be a way to document this fraud and clearly list the lies, misrepresentations and ultimately the lack of argument behind HRA as concocted by these organizations in order to deceive consumers. There could also be a list of specific scientific facts that engineers, etc., interviewed in your Audio Guide, aren’t prepared to have misrepresented or distorted to deceive consumers, etc.

    Just a bunch of lose ideas, but I think that your book shouldn’t open the possibility to be understood as yet another point of view in an open discussion, but as setting the record straight with the objective of putting a definitive stop to the abuses of the industry, advertisement and misrepresentation of science and technology.

    Cheers!

    • Camilo, there will undoubtedly be discussions about the falsehoods being heaped on consumers and my experience as a member of several organizations that aren’t working in the best interests of the public. But I plan to focus on how audio enthusiasts can simply and cost effectively improve the quality of sound their listening to.

  4. It’s a shame they have to post this garbage, myths that are outright lies about digital audio. They could have just posted the youtube video done by Monty Montgomery @ xiph.org and supported by the open source Linux organization Red Hat. If anyone hasn’t seen this video it destroys the myth of stairstep waveforms in a very simple way that the average Joe can understand, take a few minutes to watch it.
    https://www.youtube.com/watch?v=cIQ9IXSUzuM
    They also did a great digital audio primer here
    https://www.youtube.com/watch?v=FG9jemV1T7I
    Thanks Red Hat

    • While I don’t agree with everything in those videos…they do a very good job on the encoding issue.

  5. ““All music can be represented by a single, varying waveform that changes over time.”
    Of course in principle one can encode any arbitrary amount of (audio) information into a mono-dimension signal that is function of time. But if one assumes that the guide refers to an audio signal, I would expect a two-dimension signal to be more appropriate, so as to cater for the fact that we (normally) listen with both ears.

    And I am also not so sure that “music of all types .. can be reduced to a single, PERIODIC, waveform”. A purely periodic signal is only a mathematical abstraction as it has no beginning nor end. Actual signals can be considered periodic only over a short time. But even a single time-windowed periodic signal on its own is not very “musical, in my experience.

    Thanks for clarifying.

    Cheers,

    Pier

    • Pier, I’m not following you. Perhaps, I should have stated a single periodic waveform can accurately represent a very complex selection of music. If you want to do stereo or quad or 5.1…it’s the same routine. The only axes that matter are time and amplitude.

  6. From reading your posts now for months I totally understand the issue you are pointing out in this piece, and many others. Unfortunately, as you have also found out, very few people are listening, and, even fewer people care. The articles in the magazines or even the displays in the stores will garner few people who will actually pay any attention and question things to even figure out if they have an opinion on it.

    Junk equipment and low-resolution streaming (I say this about the streaming because, believe it or not, many people I know who have streaming services capable of delivering higher quality sound do not set the apps to the high quality in order to preserve their data) will continue to proliferate. Is it a lost cause? I am not sure.

    End of my “opinion” or “rant” depending on how you take it!!

    Larry

  7. I know you have railed against the stairstep model of digital audio representation but what about sample and hold circuits?

    Sample and Hold

    The Nyquist criteria defines the minimum scanning frequency as twice the maximum analog frequency to be encrypted digitally. Presumably this is because it must arrive at both positive and negative values for each cycle. The stairstep is the time averaged amplitude within each time interval represented as a number. We debated this representation versus the “lollipop” representation on another site. The scanning frequency determines the horizontal or time resolution, the number of bits per word determines the vertical or amplitude resolution. More bits and higher frequency means a closer representation of the analog signal although theoretically it will never be exact no matter how fast the scan or how many bits the word. There will always be a theoretical error no matter how small.

    There seems to be at least two different design criteria for undistorted audio, the criteria established for the audible content of music which is the RBCD standard, and the content of any audible sound even if it lies outside the range of electrical analogs of music. That I think is one of your standards but another seems to insist that there may be components beyond what is known to be the audible frequency spectrum that matter. But how far beyond? Audiophiles talk about “granularity” in the sense of photographic film or image pixilation in a digital representation but it seems to me that the transition from one value to another in audio is continuous and when the transition can be faster than the human ear can respond to, that is sufficient. The availability of over 16,000 loudness levels within about a 95 db dynamic range is much better than even JA claims he can hear which is 0.1 db increments. That would yield only 950 loudness levels.

    So which is right?

    • I’m not sure I’m following your line of thought with regards to which is right. Shannon/Nyquist is alive and well and does reproduce an analog waveform with fewer errors than any analog record/reproduce chain. In high-res coding, we get additional frequency extension and less stringent filters…which is good for the entire bandwidth. RBCDs capture and deliver virtually all of the sound of commercially released music.

      I want a system that is equal to the abilities of human hearing…and 96 kHz/24-bit PCM gives me that. I’m not on board with the “granularity” debate…that’s incorrect and doesn’t represent the output of a good digital system. The waveforms coming out of a DAC are continuous and don’t have “grains” associated with the sound or waveform.

      Word lengths give us dynamic range or a low noise floor…the same thing. The number 16,000 is loudness levels. The word lengths of 65K or 16M discrete amplitude values isn’t what JA claims to hear. He’s referring to an audio signal at different levels…although, I would challenge his .1 dB number. Even the best mastering engineers don’t get this low.

      • Once upon a time when I was an audiophile at around 12 years old, I believed what I read in the magazines, the ads, I bought it all. My first stereo amplifier, an HK A500 claimed a frequency response to 70 kHz. The University Sphericon tweeter claimed response to 40 kHz. Audio Fidelity records used what it called “The Frey Stereophonic Curtain of Sound” which claimed response out to 25 kHz. And then I went to school and learned. And after that, I not only KNEW it was not necessary to have FR beyond the range of human hearing, systems that have unnecessarily extended FR can exhibit problems those that don’t do not exhibit.

        Among my collection of phonograph cartridges are two very similar ones. One is Empire 999VE which has flat response to 20 kHz. The other is Empire 4000 D/III which was designed for playing RCA CD-4 quadraphonic recordings and has response to at least 45 kHz. They sound identical to me. (I’ve never owned a single CD-4 record or have even seen one.)

        The technique of oversampling or of extended response of CDs has the advantage of putting the low pass filter far beyond the audible range. Phase shift and FR irregularities associated with sharp cutoff filters at 22 kHz had a very noticeable effect of degrading the treble in early CD players making them sound shrill. Another advantage of oversampling is that if you sample only once and get it wrong, for that 1/44,000 second the signal is 100% wrong. If you sample 8 times and get it wrong twice, the signal is at leas 75% right.

        I do not understand the engineering validity of requiring that a system be able to capture and reproduce sounds that are audible to humans but do not exist in music. It seems like a waste of money. There are no musical signals that will have an intensity of 120 db at 20 kHz. That just doesn’t exist.

        • But they do exist in music! I agree that 120 dB SPL at 20 kHz is not going to happen but other musical signals that exceed the CD spec and reach human limits do exist. Have you ever sat next to a drummer when they hit a fortissimo rim shot? Of heard two piccolos close up? How about a Harmon muted trumpet?

          • I sit in the audience, not next to the drummer. If I did, I’d probably have to wear earplugs to protect my hearing. If you have a relative whom you don’t like, give his 11 year old son a drum set for a gift. Ah, sweet revenge.

            The loudest I can get in any documentation for a symphony orchestra is 110 dba in the audience. The softest I can get in a dead quiet empty hall is 20 dba and that is weighted. At that range, 95 db is just about enough but a greater margin would be preferable. But this range probably exists far less than 1% of the time at a real concert as the noise floor of the audience is probably a good 20 or more db higher and a symphony orchestra rarely plays with all instruments at fff so the typical range requirement is more like about 70 to 80 db.

            In this regard I think Hi Rez is over-engineering and is certainly well beyond anything pop music of any kind could require….or deserve (my opinion.)

            Audiophiles must be looking for something they don’t have because they are constantly shopping and swapping and are never satisfied for very long. I think Hi Rez shoots its technological ammo in the wrong direction. Whatever is missing, IMO Hi Rez won’t deliver it, nor will 5.1. In all fairness, acoustics and psychoacoustics still have a lot to learn and are in a very early stage of development, that is they are in a primitive state.

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