why would my sub rumble very loud when i turn my car on?

[js09 10+ year member]

I tried turning my car on today and my kicker 12" began to rumble very very loud. the radio was NOT on. I also tried turning the car on so just the battery is on and it still did it. I had to turn the gain all the way down and then drive home from work. when I got back home everything is fine.

my amp is a profile AP1000M.

maybe overheating since it was hot out today? Or bad wiring?

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[tez4life Premium Member]

Sound like a grounding issue, have you checked them yet?

 

[js09 10+ year member]

the ground goes directly onto the metal trunk frame. it is an existing factory ground and is also being used with other wires so i know it's a good spot.

 

[tez4life Premium Member]

Did it sound like you were doing a burp with it? Like it was doing just one note on its own?

 

[bonesninja 5,000+ posts]

Amp does not have soft start feature?

 

[js09 10+ year member]

Did it sound like you were doing a burp with it? Like it was doing just one note on its own?

Yep, just one loud note. It started a few seconds after I turned my car on (the amp turns on/off when the car turns on/off)

bonesninja: how can I tell if it has this feature? This is the first time this has happened.

 

[js09 10+ year member]

any other ideas? perhaps just a fluke?

 

[tru_44 10+ year member]

does it make sound when u unplug rca's

 

[js09 10+ year member]

i'm using a line out converter and wiring into the rear speakers. would i still be able to test this?

 

[bonesninja 5,000+ posts]

yes just unplug the rca's from the LOC

 

[phyphoestilic 5,000+ posts]

Yes it's probably a grounding issue. believe it or not, most factory grounds aren't at the best locations. + the connection area is usually too small. Try drilling/screwing a hole and grounding somewhere else.

What you are probably experiencing is what's known as a turn on thump. It can happen if u have a ground loop (search it up) or sometimes when ur amp doesn't have a soft start. A Soft start means there's a delay in when the head unit remote sends a signal to the amp and when the amp actually turns on. But seeing as how ur using a LOC. Where did u get the remote line to turn on the amplifier from?

 

[andytb 10+ year member]

does it happen when you turn the car to acc or just when it its on

 

[hc3_cuz 10+ year member]

i'm using a line out converter and wiring into the rear speakers. would i still be able to test this?

i had the same problem just buy a switch from radio shack and wire it into the remote wire and when u get out the car just turn the switch off so the amp turns off. most likley you have it set up where when u get out the car the amp stays on??? if so then do what i said above...