subs thumping out of tune

[jazer80]

alright i bridged both subs to one of the amps and now it's a lot louder. I moved the rca to the other side of the car and it's still making the interference noises. could it be the remote wire being close to the power maybe? this suks i hate this noise!!

[xjoeharperx]

Is the noise there when the truck is not running?
If so then it is most likely your alternator. This is normal and a sign of a healthy alternator.
The first step i would take is to get a filter and install it into the power supply to the head unit..
Make sure you have good connections and a good ground for the amps...Most people use the seat bolt for the ground..This is ok, just make sure you scrape all the paint from under the contact surface of the eye connector on the ground wire.. There is another piece called a "ground loop". This is a loop of wire that installs along with the ground wire on the grounding point and minimizes the interference..
Make sure you have good quality rca cables.. They can make a big difference in sound quality and help stop interference.
One trick I used to use was to run the head unit power off of the battery and use the factory power wire to operate a relay. The battery seems to filter out a lot of noise... Good luck..some of these problems can be a nightmare to get rid of...but not usually..

[60hz163.5db]

What kind of headunit do you have kenwood or pioneer? Cuz i have seen the internal ground fade on pioneers before mostly on the screens but all you have to do to correct this problem is pretty easy. On an rca jack there is a pin in the center and a ring around it tape a peice of barewire to this outside ring. Connect the other end of this wire to chassis ground behind the headunit do this to all rca's. Or try a friends headunit in your car if it goes away then it's prolly something internal and the radio needs serviced or replaced. But really aslong as you have your rca's opposite power. A nice short ground at the amp. And has had a tune up this is sometimes overlooked spark plug wires sending out mad radiated noise. Make sure you have a good ground for your headunit also alot of times just regrounding the headunit straight to ground helps, moving the headunits power wire off the rca's. All little things that can cause pesky noise.

[jazer80]

new rca's took care of the problem. now that i had a free amp i tried wiring it up to my speakers, and now i'm getting an even louder distortion noise from my door speakers. i ran new wires (for the speakers) from the trunk and connected them to my wiring harness behind my face. could it be that a larger wire connects to a shorter wire on the way to the speaker?

[jazer80]

i don't know how clear that is - i mean i ran new wires that were kinda thick all the way up to the front and connected them to the really thing crappy stock ones that run from the head unit to the speakers.... damn distortion sucks. (i'm out in a parking lot with my stereo pulled out of the dash, disconnecting wires. a cop drives up, looks into my car, and asks me if i'm alright. i say yes, and he just leaves. now i know how my car got robbed right under a street light in mission hill<boston>)

[xjoeharperx]

Are you using a factory head unit?..if you are using the wires that normally power speakers and you are using them for signal wires then thats your problem...Go to the store and get a "line level adaptor" it will reduce the voltage and help quiet the distortion...If you have an aftermarket unit and using the speaker wires beacuse you only have one set of rca's then go to radio shack and get a splitter and run to the other amp...or split off of the sub amp and run to the mid/high amp with the other set..this is predicated on the fact that the crossover is built in to the amp..you can also do this with an active crossover..
here is a link.. http://www.crutchfield.com/S-2fiTpin...=0&cc=01&avf=N

The splitter is probably the easiest route to go for right now..

[jazer80]

i must have explained worse than i thought. rca's are all fine, i got new ones and they took care of the problem. my face only has one external out, so i'm splitting it into 2 in the trunk for the 2 amps. one amp runs straight to the subs, the other to the front 2 door speakers. the thing is that i put in new, large speaker wire from my speaker amp, and ran it up front to behind my face, and connected it to the thin speaker wire that is part of the factory harness. i was thinking that the distortion was coming because the sound signal was going through a thicker wire, then connecting to a thinner wire before hitting the speaker. i just wanna know if this is the case before i go and run new wires ( like an idiot i got a few feet shorter than what i should have) to the doors themselves, which i really don't want to have to do unless absolutely necessary because i've never taken the doors apart on this car and have too much studying to be out there for a while.

[xjoeharperx]

Rrunnig to the doors is the best way..you are probably picking up interference from the vehicles wiring harness...

[jazer80]

you think so? i hope that's what it is, but this interference is so loud i don't know if it's just wiring. guess i'll try it i'm really getting sik of sttudying

[jazer80]

okay i went and got more wire and was told by the guys at the stereo store that w/ such low wattage there shouldn't be a problem with connecting a larger wire to a smaller one creating distortion as loud as i'm getting. i also switched my amps to make sure it wasn't the amp, and it wasn't. i started trying to take my doors apart and am lost. is there any other things i should look at before i dive into rewiring it? i really don't want to have to go through all that trouble if it's not the problem.

[xjoeharperx]

where is the power for the amps coming from?

[jazer80]

i'm running a 4 gauge from the battery to a distributor block, then i believe two 8 gauges run out of that, though it could actually be that a 4 runs into the block and comes out as another four and an eight. gg check it out, but unfortunately i won't be able to post til later, on my way to check out the jesus movie

[jazer80]

okay i couldn't figure out where the distortion was coming from, so i continued to run only 2 midrange speakers (the front 2), powered by the receiver. today i went outside and wired the back 2 speakers to my extra amp. i turned it on and it worked!! i was so excited that i actually went out to my car to do something and had success; so, i put everything back in it's place, turn the key from the accessory position, and start the car. as soon as the engine turns over and the car starts, the stereo comes back on, and there's the distortion again! this time it's on the back speakers only (as opposed to the front ones that were doing it earlier). i know it's not wiring, because i wired them w/ brand new wiring, and the amps in the trunk so it's only like 2 feet of wiring. i know the amp is in good shape because i tried it on my subs and it hit fine. i have the gain as low as possible and that doesn't help. this is the same problem i was having with the subs way before (they would be fine until the engine was on and the alternator was running), but when i replaced the rca's it fixed the problem. now i don't know what to try. i'm splitting one amp pre out to two amps, could that be bothering them? i was told it wouldn't be a problem. they're also sharing a remote wire, but i don't see how that would be a problem. please help i'm sick of my stereo always being in a constant state of repair

[PaulD]

you've broken most of the rules of good car stereo install ...and tried a lot of "voodoo" cures. Sounds like you have either a radiated noise problem or a ground loop problem. The radiated problem can be solved by using UTP (unsheilded twisted pair) RCA's. The ground loop problem is usually solved by grounding both amps at the same point. You have to face the possibility that the old amp may be bad.

[xjoeharperx]

Am i correct in saying that the distortion is comming from the speakers running off of the head unit??
If that is the case, get an inline noise filter for the power supply that feeds the head unit..