Subs pop when I turn my truck off

[Schmuck 1]

Why is this happening? I am running 2 MD3's strapped on 2 HD3 15's, an amp on each sub, and it sounds good but everytime I turn my truck off the subs pop, not like distortion pop but just not a quiet turn off. Is there anything I can do to make it a quiet turn off. It does this with the volume on 0, the shop that was able to strap my amps properly told me that it is normal with large systems. Is this true or is there something that I can do to make it turn off quiet? Is it anything that I need to worry about, is it damaging to the equipment? And my HU is a Kenwood KDC-X891 if that makes a difference. Pretty much what could be causing this? And do I need to worry about it?

[ANeonRider 3]

Use a relay on the remote turn on.

[Schmuck 1]

What type of relay? I have a Stinger 200 amp relay for my batteries what type of relay would I use for this situation?

[Schmuck 1]

Do I have to worry about it damaging anything? The more I think about it the more I think it is a grounding issue, probably with my HU. As long as it does not damage anything I can probably turn my HU off before the truck and cancel it out.

[Mark LaFountain 1,054]

I say bad ground...re-do the ground, then keep us updated

[Schmuck 1]

That what I was thinking too. I guess I will have to check all the grounds and see what happens

[Schmuck 1]

If not a bad ground what could it be? I have heard that the MD3's have been known to have these type of problems, could it just be the amps?

[sundownz 197]

Yes... it is likely just amp turn-off thump. As long as it's not incredibly loud and causing your subs to move an inch... then it won't hurt anything.

[Schmuck 1]

no it is nothing really loud just a little thump when I turn the truck off and the amps turn off. So I do not think I need to worry about it. I checked my ground and it is secure and I do not have any voltage problems so it is probably just the amps turning off.

[Schmuck 1]

It does not do it when I start the truck, however I do have a little bit of noise through my subs when I first start the truck and no music is playing so I still think I might have a grounding issue somewhere, probably with my HU.

[sqguy 0]

Do the amps get their main power cut when you shut off the truck? I swapped amps in my car and it started to pop my sub every time I shut the car off. I just had it wired to the fuse box and the only open slot shut off with the key. When I shut off HU it was quiet when I shut off car...but who wants to do that every time you get out. Other amps didn't do it but this 150w ppi did. I changed the wiring before I took it out and indeed with full power to battery when car was off it didn't do it. Apparently the amp needs power for a few seconds to properly shut down. If that is the case, you may also be getting noise at startup as the power supply in the amp gets powered up and stabilized and so on. Once in a while I would turn the key on and listen to the radio a second, then start the car. When I started the motor it cut the power momentarily and the ppi would make real strange noises in the sub powering back up. You might be able to find a relay with a few second delay if you need to have the power cut when vehicle is off. I know they make them for industrial use if you can find one that runs on 12v. You could use one to run a larger relay. Or if you are creative you might be able to hack together an old headlight/domelight delay.

Edited August 13, 2007 by sqguyib

[dave_Edwards 1]

Just as said before it is just the power supply of the amp turning off......thank God for soft start amps now a days....

[Schmuck 1]

Sqguyib that is exactly what is happening in my case. I get some noise through the sub when the amps come on and a little thump when the amps turn off. What would be good to use to remedy this. It is not hurting anything it is just a tad bit annoying.

[dopey 0]

You're using a line output converter off of a stock HU?

I've run into issues with optional factory amps (in different makes) causing turn on bumps. A switched remote line will (temp) fix it...

[Schmuck 1]

No I am using a Kenwood KDC-X891 HU not factory. However I have heard that a line converter can help tone this down. But I talked to Greg at US Amps and he said that it was normal with the amps being strapped so I guess I am just going to have to live with a little turn on and off noise. He said there was nothing I could do besides unstap the amps in which I have to tune both which is a pain in the ass, that is how it was wired before and the did not want to balance out, one sub was getting more power than the other depending on the frequencies.

[Schmuck 1]

Now that they are strapped each sub sees the same amount of power on every frequency. That was impossible to achieve with them working individually

[Schmuck 1]

can anyone recommend a good amp relay with a few second delay to cancel out the noise I get when I start when truck and the thump I get when I turn it off?

[dave_Edwards 1]

http://www.autosound2000.com/amp.htm

the amp turn off pop eliminator.......

[Schmuck 1]

that takes care of the turn off thump but what about the turn on noise?

[sqguy 0]

Are you cutting the power (+12v) to the amps with a relay when you turn the vehicle off? Not the remote wire, the main power.