[linux-audio-user] Radio Interference problems when recording

[Vince Werber]

HI...

What you are experiencing is called rectification... a major pain but 
fixable with a little work...

And yes your basement was sheilding you from the radio signals.  but that 
is moot in this case...

You were right to check your cables but have you checked your connectors 
for dirt and corrotion(sp) ??

You may need to buy some ferrite beads and place them on the cables where 
they break out to your sound panels...  generally you wind it around the 
hot leads (not the ground) and reconnect them to there respective 
terminals...

Allot of work... yes...  but it will work...

Also... high impedence mikes etc tend to do this more that balanced 600 
ohm runs so you might want to check that out...

More when I get the coffee into me :-)

vince




ka1iic at prexar.com

> This is a bit OT, but since I do all my recording on Linux machines, I thought
> I'd see if anyone on the list can help...
>
> I used to do all my recording in a basement, but since we've moved I got a new
> computer setup in our finished attic.  64studio is loaded on it (and works
> GREAT out of the box on my HP Athlon 64), and everything was working
> tickety-boo, audio running in and out of my M-Audio 1010LT via an old, beat-up,
> road-weary 16-channel mixing panel.
>
> This basic setup (different computer and distro, same sound card, cables, mics,
> etc.) was working fine at the old place in the basement.  But now when I plug
> my mics (ie: Shure SM58) via XLR into the panel, I hear a LOT of radio
> interference.  I never used to get any of this.
>
> My first thought is that the location (way up in the air) is what is causing it.
> I already tried the cheapest/quickest/easiest fix, new cables.  That made no
> change.
>
> I will try plugging the unit into another outlet and see if that helps.  I have
> the following questions for the more experienced readers on the list:
>
> 1) Could it be my beat-up old board?  Does a newer, better board (ie: modern
> Mackie, etc.) have fewer problems with RF?  (I know it would be quieter!)
>
> 2) I'm afraid that the RF might be coming through the power lines.  Any tips on
> eliminating this?
>
> 3) Is the location of my equipment (3rd storey attic) an issue?  Any way around
> this without shielding the entire roof?  :-P
>
> Thanks for any help!  Jay
>