Aftermarket Stereo/Speakers - Grounding Out?

[jmontes]

So I have installed a full aftermarket stereo in my son's 71. Alpine head unit. Alpine 5 channel amp, Rockford fosgate 5" components in the doors, 6x9's in the rear deck, and a 12" sub in the trunk. Power is ran fused from the battery to the trunk with 2ga wire and the ground for the amp is 2ga run to bolt and grounded to the chassis about 18" from where the amp in mounted in the trunk on the sub box.

Problem, when I try and screw down the 6x9's on the rear deck, the amp gets po'd and goes into protect mode. If I simply leave the 6x9's in the "holes", they play fine. Seems like once the screws touch the metal speaker frame and metal car chassis, something is grounding out. I have confirmed that none of the speaker leads are touching anything but the speaker connections in the process.

Anyone experienced this before?

 

[cv_72mustang]

Just a thought. Are the 6 x 9 speakers part of system for the kit. Most of these amps run a differential pair of signals to the speakers. I'm wondering if one terminal of the 6x 9 is referenced to ground. That would be bad for the amp?

 

[cv_72mustang]

You can use an ohmmeter to test for this condition. I'm assuming 8 ohms or maybe 4 ohm speaker. You should not see continuity (I e higher resistance ) between either of the terminals on the speaker when you reference the ohmmeter to the 'metal frame'

 

[351c1971]

OEM speaker wiring is usually grounded on one side this does not work with most aftermarket systems.

 

[Bentworker]

So I have installed a full aftermarket stereo in my son's 71. Alpine head unit. Alpine 5 channel amp, Rockford fosgate 5" components in the doors, 6x9's in the rear deck, and a 12" sub in the trunk. Power is ran fused from the battery to the trunk with 2ga wire and the ground for the amp is 2ga run to bolt and grounded to the chassis about 18" from where the amp in mounted in the trunk on the sub box.

Problem, when I try and screw down the 6x9's on the rear deck, the amp gets po'd and goes into protect mode. If I simply leave the 6x9's in the "holes", they play fine. Seems like once the screws touch the metal speaker frame and metal car chassis, something is grounding out. I have confirmed that none of the speaker leads are touching anything but the speaker connections in the process.

Anyone experienced this before?

Maybe you have a bad voice coil in one of those speakers that makes contact with the motor / basket. Look closely at the soft leads that go from the terminals to the voice coil. You could get a meter and check for continuity between the terminals and ground while softly pushing on the speaker cones. Won’t be 100% but it might show the problem.

 

[jmontes]

Thanks for the responses so far... Super weird to me. Never experienced this in any install I have ever done.

351C - Wiring is all new. The only OEM wiring I used was the power to the head unit.

I will try what others have suggested.