Hum in Wires

Archived from groups: rec.audio.pro (More info?)

"Reginald Stanton" <reginaldstanton@cox.net> wrote in message
news:wvoLe.245$5U2.113@lakeread07...
> SOUNDCARD: Soundblaster Audigy
> RECEIVER: JVC RX-888V
>
> I'm running wires from my computer to my reciever. The outputs from
> the
> computer are front L & R audio, rear L & R audio, subwoofer, and
> center
> channel (5.1). These are all standard 3.5mm stereo plugs and
> connectors
> (i.e. the front L & R audio are output from the sound card via one
> 3.5mm
> connector to a 3.5mm plug). Front audio is on one plug, rear audio on
> another, and subwoofer and center channels on the other (3 plugs).
> The same
> connectors are used for the local speakers of the computer except the
> subwoofer channel of the sub/center connect is not used, it gets its
> signal
> from front and rear audio.
>
> Each cable to the receiver is 25ft. These cables are 3.5mm stereo to
> male-RCA ends. So the end of the cable from the computer's front L &
> R
> audio go to the discreet front L and front R connectors on the
> reciever.
> Likewise for the rear and sub/center.
>
> There is a low frequency hum coming from the speakers connected to the
> receiver that is not evident on the computer's local speakers when
> they are
> connected to the soundcard. It is not very loud on the front and rear
> speakers but is clear on the subwoofer (not suprisingly, it's low
> frequency). It is there when no sound being played on the computer.
> If the
> sub/center wire is removed you can still hear it faintly on the front
> & rear
> speakers.
>
> Is there any way to prevent or correct this?
>
>


You have a ground loop. The first thing you can try is to use an
extension cord to plug the entire system (anything that is connected
with an audio cable to the receiver, including DVD player, TV, etc.)
into the same AC outlet. See if that cures the problem. If not, we can
explore more annoying solutions.

--
"It CAN'T be too loud... some of the red lights aren't even on yet!"
- Lorin David Schultz
in the control room
making even bad news sound good

(Remove spamblock to reply)

Archived from groups: rec.audio.pro (More info?)

Reginald Stanton <reginaldstanton@cox.net> wrote:
>
>There is a low frequency hum coming from the speakers connected to the
>receiver that is not evident on the computer's local speakers when they are
>connected to the soundcard. It is not very loud on the front and rear
>speakers but is clear on the subwoofer (not suprisingly, it's low
>frequency). It is there when no sound being played on the computer. If the
>sub/center wire is removed you can still hear it faintly on the front & rear
>speakers.
>
>Is there any way to prevent or correct this?

You have a ground loop. Check the discussion in the FAQ. This is why
professional systems use balanced lines.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."