first time problem sub is pulsing

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=133490
Printed Date: May 15, 2025 at 12:11 AM

Topic: first time problem sub is pulsing

Posted By: d6-karl
Subject: first time problem sub is pulsing
Date Posted: February 02, 2013 at 4:48 AM

hi guys i have a problem i have not had before which is the sub keeps pulsing.. the details

the car is a bmw7 series 2002 with the idrive and nav system. there were no signs of an amp system but i can not be sure at this time. i hooked up to the 2 rear speakers in the shelf behind the seats and used a simple low level converter from autoleads with left, right and earth connections. the earth i took to a chassis ground near the battery which is the same place i grounded the AMP. now with this setup plugged in it pulses. with out the rca plugged in its fine and it also fine with another source plugged in via rca to 3.5m jack.

anyinfo regarding this or what the problem is called so i can search up on a cure would be great

thanks
karl

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D6-In Car Solutions

Replies:

Posted By: d6-karl
Date Posted: February 02, 2013 at 3:01 PM

after a deeper look into it, it seems to pick up on the electrics when they "wake up" and pulses, have any one had this problem whilst installing intoa 7 series?

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D6-In Car Solutions

Posted By: DYohn
Date Posted: February 03, 2013 at 8:41 AM

An amplifier "pulsing" is almost always a symptom of a bad ground or input gain set way too high. I'd be very surprised if the 7-series did not have a factory amplifier, by the way.

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Posted By: i am an idiot
Date Posted: February 03, 2013 at 5:50 PM

Does the simple line out converter have any wires on it that are not connected? If so, what brand is it, and what color are the wire(s) that is/or not connected?