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sub plays a constant note

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
Printed Date: December 08, 2023 at 7:16 AM

Topic: sub plays a constant note

Posted By: poweracoustik93
Subject: sub plays a constant note
Date Posted: April 19, 2011 at 10:50 AM

So i installed a single sub in my friends car.

I installed a Jbl GT5-15 in a sealed box powered by a Rockford Fosgate P300-1 using 8 AWG wires. everything went great until we turned the radio on and listened to music.

We used an RCA adapter going through the left rear speaker because he wants to keep his head unit. for the remote wire we tapped into the interior fusebox under the pasenger side. the fuse we tapped into the ECM fuse (2A).

Anyway, When we listen to music and either turn the volume completely off or even turn the car off, the sub plays a constant note and gradually gets louder. the amp turns off whenever the keys are off and the amp turns on only when the keys are on. I'm not sure why but i think i've narrowed it down to a few things;

1) The RCA wires are too close to the Battery wire.

2) The RCA adapter is hooked up wrong.

3) I used the wrong fuse for the Remote wire.

Any help is greatly appreciated



Posted By: poweracoustik93
Date Posted: April 19, 2011 at 10:53 AM

This is in a 2008 Pontiac G6. No premium sound, just stock

Also, the EPS fuse is the Power Steering Control module

Posted By: DYohn
Date Posted: April 19, 2011 at 12:35 PM
First make sure nothing is shorted out, then adjust the gain properly. 


Posted By: poweracoustik93
Date Posted: April 19, 2011 at 12:47 PM
thanks!! i'll try that

Posted By: i am an idiot
Date Posted: April 19, 2011 at 6:41 PM
Connect the LOC to the front speakers.  And also, why would you connect to only a left or right speaker.  When you apply voltage to a speaker, it moves.  When you move a speaker, it produces voltage.  Your amp is producing sound that moves your woofer.  When the woofer moves, it moves the speaker in the rear deck.  This makes a voltage that the LOC sees as audio.  Then it tells the amp to play that note, moving the woofer, thus moving the rear deck speaker, and the cycle begins again.

Posted By: poweracoustik93
Date Posted: April 19, 2011 at 7:30 PM
thanks, but i did an install on my buddies 2002 Cadillac STS the exact same way without these problems, using the same exact LOC and wired to the same speaker

Posted By: i am an idiot
Date Posted: April 19, 2011 at 8:28 PM
Well let us know what you figure out, when you figure it out.

Posted By: i am an idiot
Date Posted: April 19, 2011 at 8:33 PM
Open the trunk and see if it quits.

Posted By: soundnsecurity
Date Posted: April 20, 2011 at 6:43 PM
i am an idiot is probably right... you are getting feedback from having the loc hooked up to the rear speakers. it wont happen all of the time in all situations but it does happen. try leaving the loc connected but unplug the wires from the rear speakers and see if you still have noise.

and i would also move the location of your remote wire from the ECM ( engine control module) fuse. if you cause it to blow it will make the whole car flip out. trust me its the last fuse you want to blow. please find a better spot for your sake and the customers.


Posted By: forbidden
Date Posted: April 22, 2011 at 11:36 AM
Just because you did something once and it worked for you does not mean it is right. You have two completely different vehicles here. You have been given advice from industry professionals yet you don't want to take it?

Top Secret, I can tell you but then my wife will kill me.

Posted By: poweracoustik93
Date Posted: April 22, 2011 at 8:09 PM
ok i found the problem, i feel so dumb. i went through my wiring and it turns out that i put the + from the LOC to the - speaker and the - from the LOC to the + speaker

Thanks for your inputs

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