[linux-audio-user] noise from soundcard

Joshua Haberman joshua at haberman.com
Thu Oct 16 18:57:44 EDT 2003

Thanks for the responses everyone!

On Thu, 2003-10-16 at 15:06, Tommi Sakari Uimonen wrote: 
> Do you hear the same noise with headphones in the Sound Blaster card and
> all other outputs/inputs disconnected from all cards?

No!!  The noise goes away completely (and I get good signal levels)!  Cool.

> I suggest that you take your electricity for the computer and amplifier
> and all that get's physically connected to them from one grounded outlet.
> And beware if you have antennas connected to the system, they give ground
> loop humming also.

I tried putting everything on the same power strip and I still get the
noise.  I have a mixer and an amplifier that the signal is going
through, and I get the same noise going:

computer -> mixer -> headphones
computer -> amp -> speakers

as I get going

computer -> mixer -> amp -> speakers

On Thu, 2003-10-16 at 15:35, Jesse Chappell wrote:
> Joshua Haberman wrote on Thu, 16-Oct-2003:
>  > This is a little off-topic, but I hope you don't mind.  I get quite a
>  > lot of noise from my soundcard.  There is a pulsing that sounds
>  > something like a very fast morse code at a consistent pitch, and it's
>  > unacceptably loud.  I notice variations in this noise based on how I
>  > move my mouse.
> It appears to be system load based, it might be an internal voltage
> interaction when your CPU goes from idle to active.  I've seen
> this before.....   try to run this at a bash prompt:
>   while true; do yes > /dev/null ; done

This takes away a large part of the noise.  There is still some noise
that sounds different, and I can still hear my mouse move.  When I move
my mouse vigorously, it starts sounding closer to what it sounds like
when that shell script is not running.


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