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as some of u may have read in another one of my threads, i installed a 4 channel amp, and am gettin alternator whine, as well as some engine noise. both goin up and down (not in volume but in pitch) as i accelerate/decelerate.

i may not be too experienced (first time i installed a 4 channel amp, i have done a 1 channel last summer). but i do know that the most common cause for this type of noise is a bad ground.

so my question is, what is the best place in the trunk for a ground? would it be the floor for example?

also, i have another 1 channel amp for my sub. is there a better way to ground my 2 amps other than just having 2 separate grounds, 1 for each?

both of my amps r mounted to the back of the rear seats.

thx in advance for the help!

 
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I use the screw on the spare tire

 
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Don't use the strut for a ground... That could be bad.

 
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tirewell is where I have mine, sand a spot and put a self tapping screw or bolt through it and you should be good to go. Otherwise there are a bunch of spots that are good for gound

 
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My initial ground was a hole drilled into the ridge directly behind the rear seats. It seemed to work okay, but I did notice a little alternator noise, especially when I had my gains turned up. When I replaced my rear speakers, I relocated the ground to the bolt that holds the rear seat in (since the seat was out anyway). That was fine, except it really didn't make much difference as far as the alt whine. I ended up installing noise suppressors on both sets of RCAs, and that solved the problem (though, from what I've read here in the forums, that's really not the best solution).

 
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both of my current grounds r on the ridge behind the seats like ur initial ground, dma. paint is ground off of course.
both of my gains r at just a bit over a 1/4 from the max, which i find is reasonably low. i also have a noise filter hooked up to the front speakers rca's. still im gettin very noticeable alternator whine.

so where should i get my ground done? and should i ground both amps in a single location?

once this is done, i wanna check if my rca's r a problem (even if they r runnin on the separate side from the power cable). i am using stinger nitros (http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5752875268)

 
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I used the seatbelt bolt on the rear-right side. You just have to sand off the paint. Haven't had any noise or other problems.

 
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I used the seat belt bolt as well - on mine it wasn't painted....

 
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I used the trunk latch for my grounds. Lift the plastic peice off and I grounded everything there. Thats also where everthing else in the trunk is already grounded so I know its a good spot.

 
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One of the car audio sites I've visited (and some members here, I think) recommends a common ground for all amps. It's my understanding that multiple grounds can somehow cause noise problems. I got my isolators at Radio Shack, and my system is absolutely quiet (noise-free) now.

 
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This might prove helpful in troubleshooting your noise problem, too. I've been meaning to get back into my system and use this checklist, but I haven't had the time lately:

Crutchfield Advisor - Noise

 
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thx dma, i have seen that page on crutchfields site before. i didnt wanna start usin it, cuz i wasnt sure i got a solid ground in the first place. thats why i wanna make sure the ground is good, and then go on with the troubleshooting if needed.

and jeffsta, i got my amplifiers mounted on the back of my rear seats. although your grounding location sounds promising, since its a factory ground, i dunno if the trunk latch's location will allow havin a ground cable of less than 18". is your cable longer?

 
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If you can use the trunk latch bolts, i agree they're a fantastic location to ground from. I tested all of the usual grounding points (struts, seat mounts, various other bolts on the floor) and found I got the best results at those bolts. Helps hide the wire too.

 
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everywhere

 
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Yeah my amp is relativly close to the grounding location so sorry I wasnt very helpful

 
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Using factory grounds is a good idea. I grounded a powered Bazooka tube there.