Soundcards and plugin-power mic's

Discussion in 'DIY Computers' started by Dean, Jan 7, 2011.

  1. Dean

    Dean Guest

    I have an inexpensive plugin-power mic that I use with my minidisc recorder.
    It gives excellent results. I can place the recorder in the middle of a
    room and record the voices of all those present, even a telephone
    speakerphone.
    The same mic, plugged in to a front panel mic input on a PC (realtek HDA
    889A) results in much much lower levels. This is with the mixer record
    level set at 100% and mic boost at +20dB. Maximum boost (+30dB) results in
    hum/distortion.


    Do PC soundcards provide plugin-power? If not, is it possible to wire the
    panel to provide it?

    Or is this disparity just down to the superior recording capability of the
    minidisc recorder?

    Any advice gratefully recieved.
     
    Dean, Jan 7, 2011
    #1
    1. Advertisements

  2. Dean

    Rob Morley Guest

    I know nothing about minidisc recorders, but I guess you have an
    electret microphone. You can easily make up a cable to power it
    with a battery and a couple other components. Here's one suggestion,
    plenty more out there:
    http://www.epanorama.net/documents/audio/electret.html
     
    Rob Morley, Jan 7, 2011
    #2
    1. Advertisements

  3. Dean

    Adrian C Guest

    The mic input might be taking a 'wanderous route' around other noisy
    signals and source I/O switching employed so that connectors can be
    reused for multichannel audio outputs, depending on OS control panel
    settings. Check it is indeed set for microphone, and also whether there
    is a difference trying the microphone connector at the rear of the PC.
    Also I've come across sound chipsets that have a jumper to connect, to
    enable the 'plug in power' voltage source.

    Failing that, if you wire the line level (or failing that, headphone)
    output of your recorder into your PC's line input connector (rather than
    the microphone socket) - and place the recorder in 'record-pause' mode
    (so that you get a monitoring signal of the plugged in microphone - you
    may need an MD inserted), then the results could be a lot better.
    Especially if you can fiddle with manual recording level settings on the
    recorder.

    --
    Adrian C
     
    Adrian C, Jan 7, 2011
    #3
  4. Dean

    Dean Guest

    Thank Robs. Using terminology found there, I searched a little more and
    found some similar solutions.
     
    Dean, Jan 8, 2011
    #4
  5. Dean

    Dean Guest

    I have tried front and rear inputs, with and without a 1m stereo extension
    lead. It makes no discernible difference. I don't appear to have any
    hardware switch for plug in power either.
    Never thought of that and it works great! The minidisc outputs on line-out
    whilst recording (whether paused or not).

    Thanks.
     
    Dean, Jan 8, 2011
    #5
  6. Dean

    Bernard Peek Guest

    The standard mic input to a PC is for a mono mic that requires power. Is
    your mic mono or stereo?
     
    Bernard Peek, Jan 8, 2011
    #6
  7. Dean

    Rob Morley Guest

    That puts me in my ignorant place - I always thought they expected a
    regular dynamic mic. but a quick search shows that Soundblasters do
    indeed put +5V on the ring of the TRS, or both tip and ring for newer
    cards that support stereo mics.
     
    Rob Morley, Jan 8, 2011
    #7
  8. Dean

    Rob Morley Guest

    It wants 2-10V on the ring (middle conductor). Apparently sound cards
    often have a jumper with which to enable this. If not you could
    probably take +5V from one of the molex power connectors inside the
    case, although it might be a bit noisy.
     
    Rob Morley, Jan 8, 2011
    #8
  9. Dean

    Bernard Peek Guest

    It's advertised as being compatible with laptop mic inputs which are
    mono, using the extra connector on the 'stereo' jack plug to provide
    power. It should work with the mic input of generic sound cards.
     
    Bernard Peek, Jan 8, 2011
    #9
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.