Hey guys I need some info/help. I recently put in a system and every time i turn the car off the subs make a loud thump noise as the amp powers off. this is really annoying and if i dont want people to know i have a system this makes it pretty hard. i have a hifonics amp with 2 10" alpine type r. I took it back to the installer and they told me there's nothing that can be done because im using the factory head unit. is that true?

 

Hmm I had that too... I thought I messed up... but guess not...

 

My sub doesn't make any noise when I turn the car off. I would have to say your installer is wrong. I am running a JL audio 500/1 v2 and a 10w6v2 in a 4080 enclosure.

 

I think it has to do with where the signal was tapped from...

 

Actually I did have that issue with my old 2001 Accord. The installer used the built in line/level inputs of the amp to turn the amp on and off, instead of running a remote wire. I guess it was a "feature" of the MTX amp i was running, anyway, it would make this annoying "THUMP" when I would turn off the car, the remedied it by running the remote wire, and not using the line/level converter built into the amp. Wonder if that is the same issue you are having?

 

i have no idea man, i dont know too much about installation so i wouldnt even know where to start looking to tell whether or not they used a remote wire or not so i can ask and they can say "yea we did" and i wouldnt know any better. Thanks for the feedback tho fellas.

 

What amplifier are you using? Also, did you purchase a JL AUDIO clean sweep, or maybe the audio control or any type of signal device to process your signals from your HEAD UNIT to your amps since the Stock HU has no RCA CAbles. If they used a cheap HI/LO converter or how your system is wired up could cause the NOISE FEEDBACK.

If you still have the receipt of your purchase, pm me and i'll tell you what could be causing the problem

 

im using a hifonics amp...i dont have a jl audio set up...read 1st post please. i still have receipt but it doesnt show what hi/lo converter they used so im not too sure if that will help me. ampdg37 i tried to pm u, but ur not receiving those right now.

 

Your are experiencing what in the industry is called turn-on thump. This is a common problem, and one reason why now most high-quality amps and processors have cricuits to combat this. Basically the amplifier is turning on before the signal from the head unit does and when the headunit kicks on you get the thump.
Our cars have more of a delay than most.. i.e. the amount of time it takes between switching XM Channels for example. Your installer, if he has any experience should be able to offer multiply solutions. If you are a DIY'er, do a Google search for variable or adjustable turn-on signal or something along those lines. There are products out there... David Navone comes to mind, he use to have a line of products for this kind of thing sold under Autosound2000brand.

In going back an rereading your first post, I see you used a pro installer....and aren't a DIY'er. He is full of it.... there are or at least use to be products that offered a variable delayed turn-on, which is all you need. He either is lazy, and doesn't like dealing with OEM upgrades, or is a tool and doesn't know what he is doning.
Although I use to be a pro installer, owned my own shop and was pretty up on all this stuff, I will add a disclaimer that this was in the early 1990's so take it with a grain of salt. But like someone said it all depends on where you tap into the signal.

 

My bad on the amp. You can pm me after you add me on your buddy list.
My only other suggestion is asking another installer to look at it. The tump you hear after you turn it on can be eliminated with a low trigger converter , p.i.e. or pac makes it. As far as the noise off the sub, it could be alot of other things. after you pm me, i can give you my cell and help you thru it

 

kinda off topic but when I saw the title of this thread as "Help! subs make thump noise" I couldn't help but smirking and thinking, isn't that what they are supposed to do?

 

yea real funny... read the whole thing!! a$$ wipe

 

thanks for all the info guys...i found out that they didnt use a remote wire and gave a BS story of how my head unit doesnt have an input for the connection but whatever...I had them install the bass *** and what i have to do is before i shut the car off turn the bass all the way off with the *** and it doesnt make the thump noise...it works so thats all i care about. Thanks again for tryin to help

 

It sometimes does that. WITH EVERY SYSTEM. It's not your fault =] you didnt do anything wrong it just the sub powering off basically