Quick Question Regarding Subwoofer "Feedback"

[manbeer 0]

Installed a 10" IDQv3 and JL 500/1 for a friend last week in 2008 G37, signal was provided from Scosche LOC connected to rear speaker leads, then 2 pairs or RCA's run to the front to a PAC Level control, 1 in, 1 out. At first we used the crappy JL signal sensing to turn it on, and after he would shut the car off especially when closing the door, he would get the loud feedback from the subwoofer, almost like it was just playing a test tone. I went and bypassed the LOC for him using a 3 foot rca, and hooked up the REM to a switched power lead on the car hoping that would help. While it isn't doing it when he shuts the door now, it's doing it sometimes when he changes songs on cd player he says. I had a problem like that a few years back but i can't remember for the life of me what i did to remedy it. Thanks in advance!!

[95Honda 486]

If the signal comes from the front speakers, you won't get the feedback anymore, but you'll loose fader control if that matters to you...

An alternative is to place a high-pass filter on the rear speakers, and make sure the LOC is taking signal before the filter. A 50mfd cap would be probably fine, just put it in sereis with the speakers as close to the terminals as possible. This will add attenuation to the driver near the feedback frequency and will more than likely help get rid of the loop.

I have had this happen to me twice, both with subs in the trunk and the LOC hooked up to the rear-deck speakers. On one system, if the trunk was closed it howled like mad. I tapped of the front speakers instead. On the other system, it would get feedback occasionally, so the highpass filter worked fine for the guy.....

[manbeer 0]

Thanks, that sounds like an easy fix, i'll try the cap thing next time i see him