Strange sounds from output

Discussion in 'Xiaomi Mi 2 / Mi 2S' started by Dimisarta, Mar 9, 2013.

  1. Dimisarta

    DimisartaMembers

    Aug 10, 2012
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    From the first day i bought my MI2 I have notticed a very strange sound coming out of the headphones output when connected on my car stereo. Firstly i tested with other devices on the same car stereo and there was no problem or stange sound at all. After a lot of test and thinking, i figured out that this strange sounds stop after you put something to play. Even if you raise the volume to the top and you here the beep sound immidiatly the strange sounds stop for a few seconds and then start again. I'm almost sure it is hardware related.

    After some more research i found out that some other devices using the snapdragon proccesors suffer from the same issue. I think the sound processor is embemded in tha cpu.

    Waiting to hear your thoughs and opinions.
    Thanks.
     
  2. moonbugz

    moonbugzMembers

    Feb 19, 2013
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    i have distortion or noise, much like an imperfect tuning of a radio station whenever I play music from it's speaker(s).

    I think my speaker(s) is broken. zz
     
  3. p3rljam

    p3rljamMembers

    Mar 2, 2013
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    Hey Guys,

    Your speakers and phones are fine. What is happening is that the sound card in your phone is energy efficient and turns off after a couple of seconds. When this happens the ground loop is disconnected and you start hearing the different components in the phone making noise as your aux cable starts acting as in inductive pickup. This is pretty common with newer phones. Nothing is wrong, nothing is broken, this is normal operation.

    Thanks,
    P3rljam.
     
    Dimisarta and moonbugz like this.
  4. moonbugz

    moonbugzMembers

    Feb 19, 2013
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    ic! it loops! such technology!
    I'll try high performance mode and hear whether it sounds differently.

    Thanks a bunch, p3rljam!
     
  5. Dimisarta

    DimisartaMembers

    Aug 10, 2012
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    Thank you very much for your answer. No it makes sense. Do you know any other devices using that technology?

    Sent from my MI 2 using Tapatalk 2
     
  6. p3rljam

    p3rljamMembers

    Mar 2, 2013
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    I've yet to find a way to keep the sound card turned on. What this forum needs, is Supercurio :)
     
  7. Dimisarta

    DimisartaMembers

    Aug 10, 2012
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    TRUE!

    Sent from my MI 2 using Tapatalk 2
     
  8. p3rljam

    p3rljamMembers

    Mar 2, 2013
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    The Xiaomi MI2 uses the Texas Instruments TPA2015D1 Audio Amplifier, which an insanely efficient class D amplifier. There will be no easy way to keep it active short of editing the kernel module. This is just something we all have to learn to live with unless somebody is dedicated enough write their own module and program to manage audio properties in a similar way as Voodoo Sound did for the entire international SGS series. If you don't like the sound the alternative is to find a way to get USB-OTC and USB Audio in MIUI to play well together. There has been success with the SGS3 to do so, there are already soundcards of which the MIUI kernel already supports but actually telling the android OS to use the external soundcard in MIUI is a bridge yet to be crossed.
     
    dextructor likes this.
  9. Dimisarta

    DimisartaMembers

    Aug 10, 2012
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    Is it so hard to write a module like voodoo sound?

    Sent from my MI 2 using Tapatalk 2
     
  10. p3rljam

    p3rljamMembers

    Mar 2, 2013
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    If you like to roll your own Linux Kernels as well as code in Java, then no. Otherwise it would be quite the challenge. I've only ever partaken in rolling kernels and dealing with never ending dependencies in Gentoo. I'll probably look into doing something like this for Xiaomi phones after I finish learning Power Shell and C# for my job. But, don't hold your breath :)
     
  11. dextructor

    dextructorMembers

    Feb 26, 2013
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    I'm testing some workarounds since yesterday evening, as soon as I conclude the testing results I'll post them.
     
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