Found: Possible Explanation for "popping" sound.

Discussion in 'Palm' started by jplaney, May 5, 2003.

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  1. jplaney

    jplaney Mobile Enthusiast

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    I don't know if any of you guys have found this out yet, but I thought I'd bring it up just to make sure. Hearing several ideas about what causes the popping sound with the zire 71 I decided to do my own simple little test. I set the sound in the prefs app to silent and then loaded up the picture viewing program and view a picture. Now, this may look kinda goofy but put the speaker up to your ear and advance the picture with the joystick. When I adavance the photos I hear a sort of static hiss as the speker powers on, even though it is supposed to be in silent mode! If you keep listening the speaker will stop hissing and power down. Now, if you advance the picture again you should hear that good old pop as the speaker powers up again for another three seconds. I wonder why the speaker is powering up even if the unit is in silent mode. Can anyone else try this out and verify what I think is happening?
     
  2. retrospooty

    retrospooty Mobile Deity

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    I tried it. I cant hear any popping sound at all. Its just not happening on my unit. It looks like just the unlucky few that get it.
     
  3. pdagranny

    pdagranny Mobile Enthusiast

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    The popping is also happening on the Tungsten C, which doesn't have the camera. To me it sounds more like a static electricity discharge.

    pdagranny
     
  4. CoolDarkKnight

    CoolDarkKnight Mobile Enthusiast

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    If you wear a pair of head phones on a computer and you don't have any music playing you can hear different sounds as you move you mouse and especially when your hard drive is running. I would have to think that it has something to do with electricty running through the computer and even thought there shouldn't be any sound going throught the sound card there is noise because your head phones are connected to the computer. This could be the same thing that is happening with the Zire 71

    *Note* Some of you may not be able to hear this inless you have very good hearing.
     
  5. jplaney

    jplaney Mobile Enthusiast

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    I was simply using the camera program because you can advance the photo with the joystick wihtout looking at the screen. It does seem that there is power running through the speker even though it is set to silent. It is very faint, so maybe some people cant hear it.
     
  6. theirishscion

    theirishscion Mobile Consultant

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    It is certainly traditional to be able to hear system activity through the system speaker. I remember the old BBC Model B (or Beeb as we lovingly knew it) had quite a good little speaker through which one could hear activity on the system bus, mostly as differing pitch and timbre of white and pink noise. A truly skilled Beeb hacker could diagnose certain hangs, loops and other occurrences just by listening. Naturally, none of this information was being piped to the sound chip, it was just electrical noise that the little audio amplified that drove the speaker was picking up. What you are hearing in your zire is the same thing. In fact, you can hear the same thing if you listen to the analogue output of your PC with a good headphone amp and pair of headphones. Different system activities will make the subtlest differences in what is coming out.

    In the case of the zire, I don't believe there is a dedicated sound chip/coprocessor/whatever, so much as some buffer hardware and maybe a plain DAC. Hence, whatever electrical noise that is bouncing around inside the case is going to affect the output of the amp.

    In terms of the 'Click of Irritation' (versus the Zip drive Click of Death) or CoI as I shall refer to it from now on, I imagine it is one of a couple possibilities, either the CPU switching power modes (sleep to walk to run or whatever TI chose to call the states) causes little voltage spikes here and there, maybe more on some machines than others (better cap here, worse cap there, but not bad enough to stop the machine working) If for example, you hold the Zire speaker hole to your ear as you turn it on, you will hear it very quiet little 'whump' as the amplifier comes alive, followed by the white noise I mentioned earlier.

    The CoI could also be caused by bad data getting sent to the DAC, or the DAC powering up or down without first muting it's output, all sorts of little tiny design goofs sneaking though. However, since I haven't noticed the problem on my Zire, I can't really comment.


    I shall however be interested to see if Palm fixes it.

    Dermot
     
  7. zinckiwi

    zinckiwi Mobile Enthusiast

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    My money's definitely on this, or some variation thereof.
     
  8. jplaney

    jplaney Mobile Enthusiast

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    That sounds like the most likely explanation....
     
  9. MapaMan

    MapaMan Mobile Deity

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    My guess is that it's Palm's effort to provide "tactile feedback" to each button press or joystick click.

    So you don't end up clicking down 3x when the page is slow to scroll, etc.
     
  10. MasterDirk

    MasterDirk Mobile Evangelist

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    Hm, I tried this turning-sound-off-and-tapping-through-photos idea, and I did hear some sounds. It sounds very faint, like something being read or written, on a noisy, but well-muffled HDD. I hae to say though, the sound of the joystick moving (physically) is much louder...
     
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