noise even when radio and engine both off

[Kent S. Rose]

This seems so odd to me. I am getting noise from my speakers even
when my radio and engine are both off. It does go away when I turn
the power off. It is worse when the engine is on and I step on the
accelerator--the whine increases.

It does not bother me when the radio is on. Presumably the sound from
the radio drowns out the speaker noise then.

I have a Chevy S-10 with a factory head unit, a Kenwood Exceleon amp,
Infinity plate speakers, and Lanzar door speakers. I have a separate
MTX Thunderform subwoofer box, with amp and speaker. Everything is
attached to high-level inputs. It was installed by a local shop,
which has despite my going back has not been able to get rid of the
noise.

Thank you in advance.

[Matthew D. Robertson]

sounds like some sort of ground issue


"Kent S. Rose" > wrote in message
om...
> This seems so odd to me. I am getting noise from my speakers even
> when my radio and engine are both off. It does go away when I turn
> the power off. It is worse when the engine is on and I step on the
> accelerator--the whine increases.
>
> It does not bother me when the radio is on. Presumably the sound from
> the radio drowns out the speaker noise then.
>
> I have a Chevy S-10 with a factory head unit, a Kenwood Exceleon amp,
> Infinity plate speakers, and Lanzar door speakers. I have a separate
> MTX Thunderform subwoofer box, with amp and speaker. Everything is
> attached to high-level inputs. It was installed by a local shop,
> which has despite my going back has not been able to get rid of the
> noise.
>
> Thank you in advance.

[Kevin Murray]

Does the noise persist when the radio is on and the volume is turned all the way
down? It's possible that your speaker wires are acting as antennas when the
radio is powered down. They could be picking up EMI and the amps would then pass
it on to the speakers as noise. When your radio is turned on it's output
impedance would drop dramatically and tend to eliminate most of this noise in
the wires.

If the noise remains when the radio is on, it's probably something else that's
been installed in the car that also remains on when the engine is off. For
example a 120V power inverter or a computer maybe? Does the fuel pump stay on
when the accessories are on? This is reaching for straws but it might help find
the source of noise.

"Kent S. Rose" > wrote in message
om...
> This seems so odd to me. I am getting noise from my speakers even
> when my radio and engine are both off. It does go away when I turn
> the power off. It is worse when the engine is on and I step on the
> accelerator--the whine increases.
>
> It does not bother me when the radio is on. Presumably the sound from
> the radio drowns out the speaker noise then.
>
> I have a Chevy S-10 with a factory head unit, a Kenwood Exceleon amp,
> Infinity plate speakers, and Lanzar door speakers. I have a separate
> MTX Thunderform subwoofer box, with amp and speaker. Everything is
> attached to high-level inputs. It was installed by a local shop,
> which has despite my going back has not been able to get rid of the
> noise.
>
> Thank you in advance.

[Kent S. Rose]

The noise does persist when the radio is on and the volume is all the
way down. But it does not get louder as the volume goes up--it just
stays as a lot of background static.

[Kevin Murray]

This indicates that the noise is entering your system after the radio. Make sure
your amps are well grounded first of all. Then check which of the speakers have
the noise present to further isolate the source. Once you find out the source,
disconnect the speaker level inputs to the respective amp and short it's inputs
(NOT the ouputs). This should make the noise disappear. If so this means the
noise is entering through the high-level input (presumably the factory speaker
wires). If not, the amp is not well grounded or it is malfunctioning.
To fix noise entering through the wires you can try re-routing the wires. If you
can't eliminate the noise you may want to ask your installer to try a
speaker-to-line level converter installed right at the radio. Another solution
that I would prefer is to switch to a nice aftermarket radio with line-level
outputs. If budget permits of course.

Do your amps remain on when the radio is powered off but the ignition is still
on? I'm wondering how the installer configured the amps to turn on and off.
Sometimes they connect the "remote" lead to an accessory position on the fuse
panel if the radio doesn't have a power antena. This wouldn't inject noise into
the speaker wires, I'm just curious how it was done.

"Kent S. Rose" wrote:
> The noise does persist when the radio is on and the volume is all the
> way down. But it does not get louder as the volume goes up--it just
> stays as a lot of background static.