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  1. #1
    Senior Member 1audiohack's Avatar
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    Digital Audio for Dummies, like Me.

    I am away from a PC and hate writing via phone so please excuse the brevity.

    I spotted this link on ProSoundWeb. It reminded me of a conversation I had with Prof Doug Jones (currently working with Danley Sound Labs) a year or so ago about digital signals and processing.

    Take a look and give it a think. I would love to discuss it more, but from a key board!

    https://www.youtube.com/watch?v=cIQ9IXSUzuM

    All the best,
    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    I really like the guy's presentation, it's obvious he knows his material. He covered bit depth quite well, I'd love to hear his explanation of sample rate.

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    Senior Member 1audiohack's Avatar
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    Hello Clark;

    Armstrong is a hero of mine, truly a giant. I have never seen the film but I will find it. Thank you for the reference.

    I assume you may have read the book, Man of High Fidelity?

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    Senior Member Ducatista47's Avatar
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    Unfortunately, I had not heard of Man Of High Fidelity. It may be a while before I can see it. At this point, used paperbacks start at $65. I will try.

    The Ken Burns DVD is not a happy experience to view, but I still enjoyed it. It is out there for $5-6 plus shipping. As you know, the near idiot Lee de Forest and the complete bastard Sarnoff made Armstrong's life miserable. The film is about how the three moved through their age. More simply, how the other two screwed Armstrong at every turn.

    The book the film is adapted from, by Tom Lewis, I have not seen but it is out there cheap as well. I just saw on copy for $1.50.
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


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    Thank you Barry!

    There is a lot of excellent ancillary stuff along with it.

    Ed
    KEEP ON LISTENING!

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    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Ed Kreamer View Post
    Thank you Barry!
    Ditto!

    There is a lot to digest there. I'll be listening to it again and follow up with his other postings. I do want to know more about the effects on transient response.

    I'll post again after more research.


    Widget

  7. #7
    Senior Member Ducatista47's Avatar
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    Nice information and presentation. I guess I was familiar with his work because years ago I downloaded and printed out the paper he alluded to in the beginning. The link to it, and many other links as well, are in the web page for this video. https://wiki.xiph.org/Videos/Digital_Show_and_Tell

    The stair step explanation (of why the phenomenon does not even exist) would be embarrassing for all the audio writers who used them as the "proof" that digital audio could not possibly be capable of accuracy or real fidelity. The ignorance (note - not stupidity) of these arguments was obvious to me, but there is no reasoning with a true believer. Now I can just link to this instead of going off and chewing tree bark.

    I also watched, first, the other video in this series, A Digital Media Primer For Geeks. https://wiki.xiph.org/Videos/A_Digit...imer_For_Geeks Tough sledding for me, but good. On the "Talk" page (comments, click the "Discussion" tab at the top), again from the web page presentation, I found this nugget that explains once and for all why 44.1 was chosen. 48 would have been nice, but there would not have been any difference in the sound. Ditto for the true believers that claimed the problem with CDs was that the sampling frequency is too low; they thought 50kHz was the magic key. One more way to think they were smarter than Harry Nyquist...

    44100 Hz Trivia


    The reason CDs use a 44,100 Hz (actually 44,056 Hz in the United States) is because, before dedicated digital recorders became mainstream, the only way a recording engineer or producer could record digital audio was with a piece of gear called a "PCM processor" or a "PCM Adaptor" (like a Sony PCM-F1 of PCM-501). These would take an audio input and, after running through the A/D if necessary, it would modulate it onto a baseband monochrome NTSC or PAL video signal that could then be recorded onto a 3/4" U-Matic video tape. The processors would accept two inputs, at 16 bits, giving a total bit rate of 1411200 bps. This number has the serendipitous property of being evenly divisible by both 30 and 25, 47040 and 56448, and these numbers allow both NTSC and PAL to encode the same number of bits, 98, per scan line (with the NTSC 480 line raster and PAL 576 line raster). It was just convenient selection of integers. CDs would be recorded at 44.1k in Europe as they were mastered onto 25 fps tapes, while CDs in the US were recorded at a "nominal" 30fps were actually at 44.056, but the difference in tone is basically inaudible. Iluvcapra 18:44, 24 September 2010 (UTC)

    Note that the PCM audio signal, once modulated to NTSC or PAL, can be recorded on any video recorder, not just U-matic. The most common tape format for PCM audio was Sony Betamax. Sony sold Betamax decks bundled with external PCM A/D converter units for the pro audio market. The PCM-F1 was designed to be used with Betacam VCRs. -- Dryo

    I do think inches per second, not feet per second, was intended.
    Information is not Knowledge; Knowledge is not Wisdom
    Too many audiophiles listen with their eyes instead of their ears


  8. #8
    Dang. Amateur speakerdave's Avatar
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    I knew it---SAUSAGE!
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Senior Member 1audiohack's Avatar
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    The book also portrays the tragedy of his circumstance. It is autobiographical and the early years of discovery and triumph through genious and absolute determination is inspiring to say the least.

    The book also underscores the utter failure of US patent law to protect the inventor against big money. Tragic. The author works diligently to factually lay to waste Lee deForest's reputation as anything but a patent troll.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    Senior Member edgewound's Avatar
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    Kinda, sorta....Pretty much...

    Quote Originally Posted by 1audiohack View Post
    I am away from a PC and hate writing via phone so please excuse the brevity.

    I spotted this link on ProSoundWeb. It reminded me of a conversation I had with Prof Doug Jones (currently working with Danley Sound Labs) a year or so ago about digital signals and processing.

    Take a look and give it a think. I would love to discuss it more, but from a key board!

    https://www.youtube.com/watch?v=cIQ9IXSUzuM

    All the best,
    Barry.
    ...lays to rest the idea that vinyl is superior to good ol' CDs.

    Great stuff, Barry. Thanks for sharing that!
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  11. #11
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by edgewound View Post
    ...lays to rest the idea that vinyl is superior to good ol' CDs.
    Does it?

    A quiet record may only be the equivalent to 10-11 bits, but other than noise floor, I'm not convinced digital is superior.


    Widget

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    Quote Originally Posted by Mr. Widget View Post
    Does it?

    A quiet record may only be the equivalent to 10-11 bits, but other than noise floor, I'm not convinced digital is superior.


    Widget
    Which brings us back to something we barely discussed a few years ago - the engineering/mastering whatever on the CDs vs the albums. I'm not sure what the deal is, CDs are technically superior, but I tend to think what is put on the CD is (sometimes) inferior. If that makes any sense.

  13. #13
    Senior Member edgewound's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    Does it?

    A quiet record may only be the equivalent to 10-11 bits, but other than noise floor, I'm not convinced digital is superior.


    Widget
    Pretty much.


    From an absolute bandwidth and lack of noise standpoint, digital has much greater capabilities than analog...but the recording itself does matter. From the video that Barry posted, the looks of a sinewave between digital and analog are identical.

    This video is indicative of what most people prefer to listen to. That said, vinyl is a more romantic ritual...if you're into that.

    https://www.youtube.com/watch?v=HnxexlHRY2E
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  14. #14
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by edgewound View Post
    Pretty much.
    I'm pretty confident that a CD playing a 1KHz sine wave will look identical on a calibrated scope whether it is played on a $30 CD player or the high end player of your choice. I'm also confident that even a casual listener will hear differences between the two players when playing a well recorded CD of music played through a high quality system.

    Therefore digital audio accurately re-creating a sine wave tells us some information, but not the whole picture.


    Widget

  15. #15
    Senior Seņor boputnam's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    I'm pretty confident that a CD playing a 1KHz sine wave will look identical on a calibrated scope whether it is played on a $30 CD player or the high end player of your choice. I'm also confident that even a casual listener will hear differences between the two players when playing a well recorded CD of music played through a high quality system.

    Therefore digital audio accurately re-creating a sine wave tells us some information, but not the whole picture.


    Widget
    I've played with this more, of late, than for many years.

    I unearthed the turntable a while back and using a Radial J33 phono pre-amp (yes, I tried several - in my price range - and there are audible differences) I've been buying vinyl with CD combo packages the past year or so. I can compare audibly (A/B) the WAV files on the CD (thru Bryston BDA-1) with the same track off the turntable. To my hearing, there's no argument - the sonic quality of vinyl is not matched by CD. I suspect there is some characteristic(s) we are not measuring - perhaps not easily measured. That said, for convenience, the vinyl doesn't get sufficient listening time!

    Anyway, to argue the point is largely mooted by the convenience factor(s) alone. And, by the lack of WAF for larger-sized audio systems required for proper reproduction. So, I balance the want with the possible/needed. When it's my turn, it's vinyl - I happy to get up flip...
    bo

    "Indeed, not!!"

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