[vox-tech] high-pitch noise when trying to raise the volume

[Peter Jay Salzman]

heh.  thanks for the compliment.  :)   but i think any electric engineer,
public speaker, or even someone who listens to a lot of rock music would be
able to identify "unbearable high-pitch noise when I raise the volume".
that's feedback.  it's unmistakable, and you did a good job describing it.

it's what you get when you take the output signal and feed it back into the
input.  in your case, the speaker output was being input into the
microphone, which was being pushed back through the speaker, which was being
picked up into the microphone, which was pushed back through the speaker,
etc...   :)

one way to deal with that is to turn off the input, meaning, either turning
the mic off (disconnecting the microphone) or turning the mic level down.

pete




On Sun 23 Jul 06,  1:51 AM, Hai Yi <yihai2004 at gmail.com> said:
> pete, you are really good! I turned mic all the way down and the
> problem is gone! Do you mind eleborating on it a little more?
> 
> Thanks again,
> Hai
> 
> 
> On 7/23/06, Peter Jay Salzman <p at dirac.org> wrote:
> >On Sun 23 Jul 06,  1:28 AM, Hai Yi <yihai2004 at gmail.com> said:
> >> hello,
> >>
> >> I have a problem with adjusting the volume when I watch the movie or
> >> listen to the music: the sound becomes unbearable high-pitch noise
> >> when I raise the volume (using alsamixer or other).
> >>
> >> I hope I could be able to provide more details, however, there is not
> >> too much info about it.
> >>
> >> Anyone experience this kind of problem?
> >>
> >> Thanks a lot,
> >> Hai
> >
> >Hmmm... Sounds like you might be hearing feedback.  Do you have a 
> >microphone
> >hooked up to your soundcard?  If so, disconnect it.
> >
> >Also, use whatever mixing software you use to mute the input.  For example,
> >with "xmix" (am I showing my age?) turn "mic" down all the way.
> >
> >Pete

-- 
The mathematics of physics has become ever more abstract, rather than more
complicated.   The mind of God appears to be abstract but not complicated.
He also appears to like group theory.  ---  Tony Zee's  "Fearful Symmetry"

email: p at dirac.org                      web: http://www.dirac.org/p    
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