P5AD2-E Mic input too low / quiet.

Discussion in 'Asus' started by Barry, Jan 25, 2005.

  1. Barry

    Barry Guest

    My P5AD2-E seem to have too little gain on the Mic input. I've the latest
    drivers and tried several Mics but still too quiet. This is causing problems
    with essential applications such as Counter Strike Source. Yes - I've turned
    up the gain in windows and Counter Strike.

    Any ideas?

    Thanks for any and all help.

    Barry
     
    Barry, Jan 25, 2005
    #1
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  2. Barry

    Paul Guest

    Congratulate the "space cadets" at Cmedia for this.

    On an AC97 chip, there is a 20dB "mic boost" button, to fix
    your microphone problem.

    In the Azalia spec, there is no provision for funny controls
    like that. The gain/loss control is a simple continuum in the
    new Intel spec. A company designing a new chip, would be expected
    to preserve the feature set of their old chips (to meet
    customer expectations), and that means mapping the old
    specifications to suit the new standard's way of doing
    things. (See PDF page 162 stepsize/numsteps/offset)

    ftp://download.intel.com/standards/hdaudio/pdf/HDAudio_03.pdf

    But, what the guys at Cmedia forgot to do, is add more gain
    steps to the gain control, so that the customer could add
    about 20dB more gain, in 1.5dB steps. I'm not convinced it
    is impossible to do, and someone just forgot.

    You may need to buy a preamp of some sort. The type of
    preamp may vary, depending on whether your mic is
    electret or a dynamic type.

    While many chip bugs these days are fixed by a driver
    update, something tells me this is truly busted, and a
    new chip revision will be needed to fix it.

    Best guess,
    Paul
     
    Paul, Jan 25, 2005
    #2
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  3. Barry

    Paul Guest

    If you have a better head for numbers than I do, compare an
    AC97 chip, to the CMI9880:

    ALC650, an AC97 audio chip. Data sheet version 1.28 . Page 10
    has microphone volume of +12dB to -34.5dB in 1.5dB steps. On
    top of that, there is the 20dB boost button. Max gain in
    that stage is 32dB.

    ftp://202.65.194.18/pc/ac97/alc650/alc650_data5.zip

    The CMI9880 seems to only have gain in the "input widget".
    It has 32 steps of 1.5dB and an offset of zero. This
    implies a gain of from 0 to +46.5dB, and the rest of the
    spec doesn't seem to have any attenuation capability.
    The microphone in the ALC650 has a range of +32 to
    -34.5dB, or a total range of 66.5dB .

    http://cmedia.com.tw/doc/C-Media CMI9880 Datasheet rev 0.99C.pdf

    The CMI9880 just doesn't make a lot of sense to me.
    Maybe someone else can explain this to me. A chip
    that only has gain, doesn't make a lot of sense,
    when you want to turn it down :)

    Paul
     
    Paul, Jan 25, 2005
    #3
  4. Barry

    Barry Guest

    Well I've sent the problem to ASUS support. They came back quickly but with
    the standard refer to this page in the manual for the level control. I've
    replied yep, got that max'ed already. We will have to see what they can do.
    Good news is that I googled and I not the only one that has noticed the
    problem.

    Thanks for the info

    Barry
     
    Barry, Jan 26, 2005
    #4
  5. Barry

    Barry Guest

    So what is ASUS's answer to one of their flagship boards having a problem.

    1. Have your dealer test it. They know less than me.....I.T. professional
    for 14 years.
    2. RMA it back here so we can take a couple of weeks sending you the same
    board version again. Oh, that's worth while!

    Well I'm unimpressed. I wonder how long it will take for a clue to filter
    down to the techies at ASUS from the users in the real world who actually
    know it's a problem.

    I'm guessing a USB based microphone will have none of these problems and so
    I may try one of those next.

    All the best

    Barry
     
    Barry, Jan 28, 2005
    #5
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