2008 accord sub w/factory headuni

ok i mainly post here about alarm install questions but this install i did last night has me stumped. when the doors were open everything sounded finebut when she closed her doors and drove off the hi/low converter started making the subs pound twice every 10-15 seconds. this is anytime every door is closed including the trunk. the converter i used was a PAC SNI-15 with no adjustments on it. the car does have 7 speakers including a factory sub but does not seem to be amplified because the converter works but just does the pounding thing. any help is appreciated.

keep the converter hooked to the speaker wires but unhook the speaker itself. if it goes away then you are getting feedback from the subs physically moving the speakers that are in the car which creates a feedback current and shows up in the subwoofer as sound.

If you wish to keep the speakers connected, you will have much better luck placing the SNi-15 behind the factory radio.  This will almost always solve that problem.  Are there any microphones located in the headliner or in the rear deck next to the speakers?  If so, you need to disconnect them.

i am an idiot wrote: If you wish to keep the speakers connected, you will have much better luck placing the SNi-15 behind the factory radio.  This will almost always solve that problem.  Are there any microphones located in the headliner or in the rear deck next to the speakers?  If so, you need to disconnect them.

i took the car to the shop where i bought the converter from and they fixed it for free for me in 5 minutes. they said it was because the 2 brown grounds on the converter were connected but i grounded them after the first time she said she heard the sound but o well problem fixed

If she powers her radio down, it will probably happen again.  Just let her know to keep her radio turned on, just put the volume all the way down if she does not want to listen to it.