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Re: No sound-inputs but sound recording FMIT




https://packages.debian.org/jessie/fmit
https://packages.debian.org/stretch/fmit

Here are the two current versions of it and I like it because it gives a
little more control in tuning out noise and concentrate in what I want
to measure.

It is most probably electrical noise and fluctuations of voltage and/or
frequency, which may get amplified to look like an unstable wave form.

This part may be understood enough to leave it to the sound experts.

What is interesting is that a mechanical vibration may actually cause
electrical contacts on the whole system to create an instability within
that electrical noise.  One does not need to be a sound physicist to
translate this into an effective microphone.  How many pc's don't have
panels that act as drums and amplify noise and transform noise into a
mechanical vibration?

No, there is no onboard mic, there are only two audio inputs front and
back, and as I said trying this in 2 other systems with different debian
builds had similar results (some noise registering and affected by
abrupt vibration).

Yes I have pavucontrol installed, pulseaudio and utils.

PS  Suddenly, the noises in one's head that nobody else hears are
recorded by one's only true friend, the PC   :)) :)))

deloptes:
> GiaThnYgeia wrote:
> 
>> I don't see how the previous got linked to a previous thread so I am
>> reposting with additional clarification.
>>
>> OK, I did some testing on an other machine with a testing installation,
>> downloaded FMIT (an instrument tuner that will pickup audio input/analog
>> and tell you all kinds of stuff about the wave that is fed).
>> Same exact behavior, hardware only lists two audio inputs and are both
>> unplugged.  The lower the db threshold for sound recording the more
>> apparent the sound becomes.  Each knock on the box shows corresponding
>> amplification of that noise.
>>
>> Ok, so I picked up 2-3 live debian based USB sticks I have.  I plugged
>> then in to 3 different machines, downloaded FMIT and run it.  Similar
>> results.  So it has nothing to do with my configuration of stuff.  I say
>> if some software is picking up sound from your environment and records
>> it when no inputs are plugged in I would call this a "security" issue
>> not a malfunction.
>>
>> What is there MORE to post so it can be reproduced?  Blank live debian
>> installations adding FMIT in 3 machines Jessie + Stretch (one on UPS,
>> one on mains-plug, on laptop) if you allow it to see a wide spectrum of
>> frequencies it records noise (mostly hi-freq) and only hardware inputs
>> are unplugged.  Where is the noise coming from?
>>
>> It probably has nothing to do with the program itself but its
>> dependencies and some code feeding in wrong data as audio input.  But it
>> is actual sound
> 
> I was interested in your mainboard - perhaps it has integrated mic.
> 
> Do you have pavucontrol installed? Go to input devices and mute the mic
> 
> regards
> 
> 

-- 
 "The most violent element in society is ignorance" rEG