USB headset microphone picking up line/speaker output

Discussion in 'PC Hardware' started by Paul, Feb 17, 2013.

  1. Paul

    Paul Guest

    When you have two entirely different pieces of hardware, it's
    pretty hard for the signals to just meander from one piece of
    hardware to the other.

    How loud a person talks, can be a function of what they hear.
    And to stop people from shouting while wearing a headset, they
    sometimes mix some microphone signal, into the earphones.
    That's so the speaker will talk at a more normal level,
    and not exaggerate their speech.

    Your wiring would have to be particularly poorly shielded, for
    coupling between conductors with a large separation. I'd choose
    to believe it's a software trick instead. Like some mixer or
    sound driver, knows headphones are involved, and some
    mixing of input with output is required for better perceived
    ambient sound.

    Paul
     
    Paul, Feb 17, 2013
    #1
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  2. Paul

    John Doe Guest

    Problem is... I'm using a Logitech headset microphone for
    sound/speech/command input. My computer does what I tell it to do.
    Unfortunately, seems that sometimes it hears sound that should be
    piped only through the speakers. I'm sure it's not hearing the sound
    coming from the speakers, it appears to be something in the circuitry.
    In other words... I use a USB headset microphone for speech input.
    Sound output is through speakers. But the system appears to be piping
    sound output into the headset microphone circuitry. This has happened
    with two different Logitech USB headsets.

    Seems that the problem occurs even when the speakers are muted.

    I might try a spare soundblaster audigy sound card, using the speaker
    out from that instead of from the built-in sound. Somehow, maybe that
    won't interfere with the USB microphone input.

    Not that it matters, but... I'm using Windows Speech Recognition and
    Vocola for voice-activated scripting, in Windows 8.

    Thanks.
     
    John Doe, Feb 17, 2013
    #2
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  3. Paul

    Flasherly Guest

    Most newer boards offer AEC for echo cancellation to gamer forum
    taunts or service site relays on copper multiplexes and satellite
    telephony. Can be a pain without it on telephones for the receiver
    listening to a computer, as the mic and speaker balance may sound good
    to the computer operator, encompassing both parties transmission and
    reception, but horrible to listen to for the receiver only. AEC
    effectively knocks out the computer speakers from feeding back into
    the mic.
     
    Flasherly, Feb 17, 2013
    #3
  4. Paul

    John Doe Guest


    I appreciate the feedback, y'all.

    The problem doesn't exist using the same USB headset microphones in
    Windows XP with Dragon Naturally Speaking.

    In windows of old, sound properties included sliders for various
    recording sources. The choice of recording source sometimes included
    WAV output.

    Another weird thing is that the very same WAV sounds can be played at
    the same volume from the file manager, without interfering with speech
    recognition input. The problem occurs only during script playback when
    using those sounds as queues.

    Vocola voice activated scripting uses this command.

    RunProgram("D:\files\wav\special effects\boop.wav")

    Apparently that just opens the file using the assigned program. But I
    suspect it could be somehow related. Lousy lead, but that's about it.

    I'll try plugging in the sound card. If that don't work, oh well, I'll
    definitely post the fix if and when I find it. I use sounds regularly
    for script playback.
     
    John Doe, Feb 18, 2013
    #4
  5. Paul

    John Doe Guest

    It's not speaker output feeding back through the microphone, the
    feedback happens when the speakers are muted. But it's inconsistent. I
    think it changes when I run a voice activated script. So I think it
    has to do with Windows Speech Recognition and maybe Vocola. For some
    strange reason, WSR starts (and stops) listening to WAV output as well
    as microphone input. I suppose it's a bug in WSR, but conceivably it
    could have to do with Vocola.
     
    John Doe, Feb 18, 2013
    #5
  6. Paul

    John Doe Guest

    BWAAAAAHAHAHAHAAAAA!!!

    Solved.

    For the record. According to Eric from an Windows Speech Recognition
    web group/forum...

    This is the echo cancellation from the audio object. Disable it by
    making this DWORD value and setting it to 0, in the registry.

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech\AudioInput\AudioFeatures
    \AcousticEchoCancellation

    The registry key AudioFeatures didn't even exist, but adding that
    setting appears to stop the interference. Disabling echo
    cancellation solves a problem that looks like echo. Strange but
    true.
     
    John Doe, Mar 13, 2013
    #6
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