common ground point

Hey all... I'm wondering about moving my amps over to a common ground point in my vehicle. I know that MECP states that this is standard practice, but the way I was taught (not saying that it's right... it's just the way I was taught) was that it's just fine to ground the amps in separate locations because you want the ground to be as short as possible.

So therein lies the question... The only way for me to get a common ground is to extend out the length of one of the amp ground cables quite a bit. Is this going to matter?

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MECP Basic Installation Tech
Certification ID: CEA195600
Pioneer AVIC-X920BT
Polk Audio DXi 6500 - front
Rockford Fosgate Power T1693 - rear
Alpine MRP-F300
Alpine MRP-M500
Alpine SWR-1242D

The concept of common ground point is to eliminate the possibility of ground loop, where multiple ground locations create a noise heard through the system.  With one ground point, there is then only one reference.  If your system sounds good; no noise that shouldn't be there, then there is no reason to change your grounding.

The best course of action when you want to use a common ground point is to actually ground each piece of equipment to its own drilled location where each ground point is about an inch away from the others.  This keeps you from resorting to stacked grounds on one common bolt (which can result in poor grounding for some or all of the gear) while keeping all the grounds so close that they are essentially the same location.

And the ground wires don't have to be very, very short, either.  The idea there is that the vehicle's mass is going to create a greater (less resistance) return than any ground wire could, and therefore a longer ground wire will almost certainly result in increased resistance for that amplifier.  This, of course, is not always the case.  See the stickied subjects on grounding.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

^Great answer.

Is there any reason why you are trying to reground everything? Or are you just doing it? lol

I wouldn't do it unless it made things easier on you. If your system works fine now then I do not see why you would need to change it. If you are just trying to find something to install then I sympathize with that. lol

And yea the chasis ground has so much more conductor surface area than any size wire could have. As long as you you use the same same gauge as your battery wire then you should be fine no matter how long you need to extend it.

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MECP Advanced
Make your life easier and buy a DMM.

Just reading through the MECP Advanced book and it was stated that it was standard MECP practice to have a common ground so I thought I'd throw the question out there. I do have a car that has a unibody frame, so it's not always the easiest to find a good ground point close to where my amps are being located. Where I have them works for now, but whenever I start my actual build I'll be looking for a new place to ground them as well as having a very clean wire run.

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MECP Basic Installation Tech
Certification ID: CEA195600
Pioneer AVIC-X920BT
Polk Audio DXi 6500 - front
Rockford Fosgate Power T1693 - rear
Alpine MRP-F300
Alpine MRP-M500
Alpine SWR-1242D

If you don't have ground loops and related problems, then your ground is ok.
"Don't fix it if it isn't broke."

Adding long(er) grounds for a common ground can introduce problems.

Thanks... that's all I wanted to know. Just wanted to make sure I wasn't missing out on something by NOT having a common ground point. I'm sure that when I build my amp rack, I'll do a common ground off of a distro block, but that's somewhere down the road.

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MECP Basic Installation Tech
Certification ID: CEA195600
Pioneer AVIC-X920BT
Polk Audio DXi 6500 - front
Rockford Fosgate Power T1693 - rear
Alpine MRP-F300
Alpine MRP-M500
Alpine SWR-1242D