Jitter

Discussion in 'Audio Hardware' started by Paul_70, Nov 26, 2015.

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  1. Paul_70

    Paul_70 New Member Thread Starter

    Is 'jitter' a real phenomenon or just something invented by journalists? In my mind 'jitter' is the new wow & flutter. Given that wow & flutter are both considered technically infeasible with digital playback is jitter just something invented by reviewers and critics?
     
  2. timztunz

    timztunz Audioista

    Location:
    Texas
    I believe it's real. But what comes now will likely be very interesting.
     
  3. Sneaky Pete

    Sneaky Pete Flat the 5 and That’s No Jive

    Location:
    NYC USA
    Jitter is real and efforts to reduce it can improve sound.
     
    timztunz likes this.
  4. Paul_70

    Paul_70 New Member Thread Starter

    More specifically - and I should have put this in my opening post, jitter is definitely a real phenomenon in digital data systems and can have unwanted side effects in terms of packet loss and packet re-transmission etc. (IT background btw).

    But with red book CD audio 'only' demanding 1,411,000 bits per second then surely a cable that can shift 1,000,0000,000 bits per second the timing fluctuations are miniscule and thus will not have any effect at all upon the analogue signal that the DAC outputs??

    Thanks for not flaming me btw :)
     
  5. Captain Wiggette

    Captain Wiggette Forum Resident

    Location:
    Seattle
    Jitter is an engineering fact. That is, jitter is absolutely measurable by test equipment, and exists as a physical reality in digital circuits and digital signal transmission.

    Whether jitter is audible has been widely debated.

    I have no opinion on the matter, and less interest than ever simply because I listen mostly only to vinyl. But I'd be pretty skeptical about audibility claims regarding jitter.
     
    SandAndGlass likes this.
  6. Captain Wiggette

    Captain Wiggette Forum Resident

    Location:
    Seattle
    By the way, while again forwarding no opinion about audibility (besides skepticism), jitter is really the only method by which a digital audio cable could influence audible sound (if functioning - that is not total transmission failure and no sound at all). Cabling capacitance does cause jitter to increase across a digital interface, and low capacitance can be an important goal for digital cabling especially over long distances, to reduce this. At extremes and very long distances, digital signal failure can occur entirely, and the signal is simply not recoverable at the other end. This is extremely rare (total failure) with digital audio, given, as you say, the relatively low-bandwidth needs for SPDIF and the like, but it is pretty common with digital video (much much higher bandwidth) or even Cable TV/Satellite feeds over longer distances.

    But as far as run-of the mill 'I can hear that' with regards to jitter across a digital audio interface, I've not seen any evidence of that (besides anecdotal claims), but neither have I tested it. Hence my holding no opinion on the matter.

    But all of these things are certainly measurable. As far as the endless claims of audiophiles that you can't measure what they hear, I don't know if measurability is evidence for or against audibility. I fear logic is probably the wrong approach to apply to the matter.
     
  7. Steve Hoffman

    Steve Hoffman Your host Your Host

    Jitter, love that band. Saw them in concert and their lead singer kind of scared me. Best to hear them without seeing photos. mugly.jpg
     
    Dan Steely and Gavinyl like this.
  8. tootull

    tootull Looking through a glass onion

    Location:
    Canada
    [​IMG]
    Jitter, jitterbug, all works of the devil.
     
  9. tootull

    tootull Looking through a glass onion

    Location:
    Canada
    Yes.
     
  10. RonW

    RonW Forum Resident

    Location:
    New York
    It's nothing more than the commonplace ringing present on every digital signal. You're not gonna hear it.
     
  11. Paul_70

    Paul_70 New Member Thread Starter


    Captain - thanks for your response. I am truly interested in investigating this. Much as my OP suggested that it's all the same, I, too, am a vinyl fan, Is it accurate, well no, not necessarily, and nor is any digital source. Accuracy is less important than perception. If I perceive something to be more pleasing ot pleasant then that's all that is necessarily.

    I am a CD hater and diesel hater. But I am starting to get acquainted with both. Blimey, I even have a diesel car. Do I like it? No. Not because of the engine, it's just a bone of a car.

    Best regards
     
  12. head_unit

    head_unit Senior Member

    Location:
    Los Angeles CA USA
    So we gotta ask...is it a VW group product?:hide:
     
  13. Stone Turntable

    Stone Turntable Independent Head

    Location:
    New Mexico USA
    Jitter must be the worst audio technology term of all time, because the word sounds like a specific audible distortion in the way that a person with the jitters is twitching in a distortion of ordinary movement. When in fact it simply means "a deviation from the ideal timing of an event" and is not something most of us are ever going to hear as a noticeable degradation of digital playback.
     
    SandAndGlass likes this.
  14. Paul_70

    Paul_70 New Member Thread Starter

    Yes. Not that I have an issue with the emissions. The engine is fine, it's everything else that's bolted to it - ie the rest of the car !!
     
  15. Paul_70

    Paul_70 New Member Thread Starter

    Nicely put ST! I'd like to add that in highly stressed data networks jitter can cause packet loss and this requires retransmission of said packets. The impact being a slight slowing of throughput.

    But audio is very undemanding - there's lots of slack. Besides which the interfaces each end of the interface will be buffered anyway.

    By which I mean is that I can't hear jitter.
     
  16. Steve Hoffman

    Steve Hoffman Your host Your Host

    I used to worry about Jitter so much, would lie awake thinking about it. Then I tried an Audio Note UK digital two box DAC and transport that has no Jitter control whatsoever. It sounds fantastic. I no longer lie awake thinking about it. I think about girls instead.
     
    SandAndGlass, russk, jpelg and 6 others like this.
  17. Paul_70

    Paul_70 New Member Thread Starter

    So can we assume that jitter does not cause problems with digital audio playback?
     
  18. Erik Tracy

    Erik Tracy Meet me at the Green Dragon for an ale

    Location:
    San Diego, CA, USA
    Based on what...some posts on the internet?
     
  19. adamdube

    adamdube Forum Resident

    Location:
    Elyria, OH USA
  20. Kyhl

    Kyhl On break

    Location:
    Savage
    You should also know that audio over USB does not retransmit lost packets. Lost audio packets are lost so take care in transmitting them properly.
     
  21. Paul_70

    Paul_70 New Member Thread Starter

    I genuinely didn't know that! Surely USB must employ some means of error correction otherwise any data carried over USB will be corrupted in the same way.

    I understand that SPDIF is not packet based.

    But USB and Ethernet carrying nothing more than a string of digital audio should not really an issue.

    I'm asking because I am interested to know the views others have of high end digital interconnects etc.
     
  22. c-eling

    c-eling They're made of light,We never would have guessed

  23. rhubarb9999

    rhubarb9999 Forum Resident

    Location:
    Atlanta, GA
    Jitter is a real as global warming :hide:
     
  24. tootull

    tootull Looking through a glass onion

    Location:
    Canada
  25. Mal

    Mal Phorum Physicist

    Digital audio isn't just about transmitting data robustly.

    You listen to the data stream as it comes out of the DAC filter in real-time. Feed it into the DAC without keeping jitter to a minimum and you risk introducing audible error in the reconstructed waveform (you get a 'confused' version of the original).

    Where is the audible threshold? Dunno.
     
    Robin L likes this.
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