You installed an aftermarket radio and hooked it up to your stock speaker system.  Now your factory subwoofer pops when you turn your vehicle on.

 

If so it could be caused by an improper voltage going to the factory amplifier.  This is generally the case with aftermarket head units and newer Ford products.  Aftermarket head units will send a 12V signal to turn on the amplifiers.  Some Ford factory amplifiers (and possibly other makes as well) need 5V other wise they produce a loud pop when they are turned on. 

 

The SMT-AI will drop the voltage of the amp turn on from your aftermarket head unit so your factory amplifier will not “POP” when you turn on the vehicle.

 

 

I built one of these for my own 2003 Lincoln Aviator.  I was told that this seems to be the solution for Ford Explorers, F150’s, Mustangs with “Shaker” radio systems, vehicles like those.

 

 

Couldn’t you just go out and get your own 5V regulator and wire one of these up yourself?  Sure, information on this circuit is on my technical support page here. Or if you want to make it easier on yourself, just order mine.

 

 

NOTE

There are other possibilities which can cause “popping”.  The main one seems to be that the amp is turning on before sound is sent to it from the head unit.  For more information please check the tech support page for this item here.  I will list a bunch of links and a way to test if this is your problem.