Binaural mics - HELP PLEASE

Discussion in 'General Electronics Chat' started by krow, Jan 30, 2011.

  1. krow

    Thread Starter Member

    May 25, 2010
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    Hey guys,

    I've been trying to build a pair of binaural mics into one single stereo mini plug as in the kypkay tutorial on YouTube (I hope you know what I'm talking about) and this task seems just impossible, I also followed the instructions given in Make Magazine, instructions which are slightly different from the ones on the tutorial (the wiring is not the same), and the results have been the same, failed!

    Sometimes I get either sound from only one headphone, sometimes from the other or sometimes I just get sound from both but no binaural image is present, I tried everything and I'm about to give up cuz I just don't get what's wrong. Can anybody tell me exactly how to wire the mics to the 3.5mm plug? has anybody built this before? I'd appreciate it a lot since I'm going to start working on a university project based on holophonics and all this stuff, the funny thing is that the project hasn't really started and I can't even build a pair of binaural mics :S

    Thanks a lot.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    3.5 mm plug wiring - http://pinouts.ru/Home/Tele35s_pinout.shtml

    Wire grounds all in common. The right mic and left mic signals to the appropriate pins.

    Can you solder, and do you have access to heat shrink insulation?
     
  3. krow

    Thread Starter Member

    May 25, 2010
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    Thanks for your reply! I'm not an expert in the field but sure I can solder, I have heat shrink insulation, I mean I did exactly what's in the video but there's always something wrong :S

     
  4. bertus

    Administrator

    Apr 5, 2008
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  5. Adjuster

    Well-Known Member

    Dec 26, 2010
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    This should not be difficult. I assume that you are using microphones with ordinary unbalanced single screened cable, that is to say, cable with a single insulated centre conductor surrounded by an outer screen conductor.

    The connections are as follows:

    Sleeve: Outer conductors of both cables.

    Ring: Inner conductor of right cable.

    Tip: Inner conductor of left cable.

    Of course, for this to work you will need two WORKING microphones. Are you sure both of them are good?

    http://en.wikipedia.org/wiki/TRS_connector
     
  6. krow

    Thread Starter Member

    May 25, 2010
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    @ Bertus thanks for the info, I'll take a look.

    @ Adjuster, well...I hope I'm not making a careless or stupid mistake but I'd like to show you in this photo what my mics, plug and wires look like. The plug, mics and wires work fine, I tested for continuity, I checked the mics and the plug and they're all good, is it the type of wires I'm using...? if that's the problem then I'm sorry for wasting your time, however, you'll still be helping a lot if you tell me THAT's the problem.
     
  7. krow

    Thread Starter Member

    May 25, 2010
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    Oh, and I did the same as you wrote and still failed:

    Sleeve: Outer conductors of both cables.

    Ring: Inner conductor of right cable.

    Tip: Inner conductor of left cable.
     
  8. beenthere

    Retired Moderator

    Apr 20, 2004
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  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Do you have any information on the microphones, such as a datasheet?

    The problem appears to be what beenthere stated above. However, to give you information on biasing the mic's, any extra information would be a great help.

    It WILL work, just with some extra components and a power source. Unless your camera has a bias power out type jack, then you need to connect to it. What make/model is the camera?
     
  10. Audioguru

    New Member

    Dec 20, 2007
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    The photo in post #6 shows two electret mics connected with no shielded audio cables. The ordinary twisted "telephone" wires will pick up lots of mains hum plus other interference.
     
  11. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Even if your recorder provides the power for both channels, beware that the mics have polarity, the pin that seems to connect to the outer shell is usually ground.
    Generally i think you will be better off buliding your own preamplifier and then feeding its output to your line input.
     
  12. krow

    Thread Starter Member

    May 25, 2010
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    0
    I found the problem and it was very simple, it turns out that my laptop has a mono input and I didn't know :p I would've saved a bunch of time and stress, thank you all for helping me out anyway.
     
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