Help... what size wire do I need? (ground)
 

Okay, so in my 04 Rx8, I'm running a smaller system. Just a 600w sony xplod amp, and a 12" MTX Blue thunder sub, sealed box, and using a LOC. I'm running an 8 gauge power wire down the driver's side panel, using the rubber grommet to get through the firewall. Now this sysem, I'm used to just grounding to chassis, so I did, using the spot where the spare tire kit would go, as i heard of people using it, and I tested my self, and got little to no restistance. After all connections were made, I tested my system out, letting the engine run to keep the battery charged, all was good until about a minute into listening at high volume, it started clipping, like mute for half a second, then picks up, and keeps doin it until I turn it down. It almost seems like the vibration may be just skipping the disc like hitting a bump in the road, but none the less, I couldn't help but to think twice about the ground.
So after thinking about it, I decided I do in fact want to run my ground back to the battery now. With using my set up (8 awg & 600w amp), do I need to run a larger ground wire than 8 awg? Or will I be okay with running the same size back to the battery? Can I expect any alt. whine, or noise?
Thanx for any help you guys can give.

8 awg is a bit small for a 600w amp. What size fuse does the amp take? You may have up to about 1v drop over wire that size depending upon how long the run is and what the current draw is. (100A over 20 ft will be about 1.2v.)
I'm not sure why it would run fine for a while then drop out due to cabling or grounding. The amp isn't getting too hot is it?
You may want to look into upgrading the alternator's ground rather than running 8ga back to the engine bay.

Sounds like the amp is kicking in and out of protection to me. 2 ohm load on a bridged 2-channel amp by chance?

yeah thats not something to do with your ground. That sounds like protection, your subs are running too hard for the amp to handle. Firebirddude sounds right on this. And you dont have to run all the way back to the battery. Where you did isnt the best, theres paint there but theres plenty of good ones besides that. And you tested low impedence, so ur good there sounds to me. Could be ur remote wire connection is poor too. That would cause the amp to cut in and out especially with the vibrations of the sub.

Sorry I was away for a while. Been busy.
Yes, it's a 2 channel amp, bridged. I'll look into the remote on wire connection (to 12v outlet) and try bringing the gain down a bit. When I made my ground, I was sure to sand off the paint. Aside from that, where else would you suggest grounding? I have some 6 gauge wire and 8 gauge wire layin around. When I originally bought this equipment, best buy recommended 8 gauge, in my Mazda mx-6 LS. Now it's in the Rx8 still using the 8 gauge for power and ground. When it gets warmer out, I plan on really getting this finished the way I want it, and feel confident that everything is safe. I'm pretty confident in it so far, and perhaps I have the gain up a bit too high, I'm used to just adjusting it at the amp and head unit. Now I'm throwin in the LOC and I pretty much just left it at 3/4 the way to max, and adjusted the rest from the amp at volume 25 on the stock unit. I think I'll re-tune it all with a subwoofer test track or somethin. Thanks guys. And any more suggestions would be appreciated.

its your amp either your trying to run a ohm level your amp cant run or like others said that sub is too mich for that amp your ground should be fine and long as its aginst good bare metal i run 8ga with my 600watt dd amp and a 8ga ground.

I think 8 gauge should work fine. Are you sure its 2 ohm stable mono?

What is your crossover set to?

I grounded to the same location. Used 4 gauge wire. 8 gauge is fine, just fuse it correctly.

Well i can't say it's the on off switch, it's a nice splice connection on the 12v plug in the center console, seems to be fine even if I try shakin it around.
Crossover you mean my LOC? It only has gain control on it, and I originally set it about 3/4 the way up, I have it turned down to more like half, and just moved my the gain control on the amp to a little above half way up. It doesn't hit as hard, but it doesn't cut out the sound if I have the volume up for a while like before.
You guys may be right on the amp not being enough for the sub, but why didn't I ever have this problem before in my Mx-6? I even had the gains much higher up. The only difference is now I'm using a LOC rather than plugging into an aftermarket HU. Also, I may be wrong here, but if the sub is asking too much from the amp, and it cuts into protection, why would it cut the rest of my sound from my speakers, and not just the sub?
I can deal with my gains set as they are, considering there are enough rattles to work out as it is. But I would like to overcome it and be able to turn it up without any concerns.
As of now, I kinda scratched the idea of running ground back to the batt, and will assume the 8gauge will be ok for now. Although I do kinda like the idea of the battery grounding kit in the DIY sticky. It seems that it could only help. It doesn't look like that big of a project and I have easy access to most if not all of the materials.
Thanks for your help so far guys. Any more ideas are much appreciated.

You should have crossover settings on your amplifier. It will consist of a switch for "Low pass" and a knob you can turn. Many amps let you adjust the low pass filter between 50-300 hz or so (YMMV). you want to set that knob to 70hz or so as a start, then adjust to taste.

I had this problem on the system in my accord. If your crossover is set to high, your amplifer will send signals to the sub that it cannot play and you can trip the amp into protect mode. It will also sound boomy and distorted.

The level coming out of the Line output converter is not going to be the same as what came out of the head unit. Try turning the gain on the LOC down as low as it will go, and the gain up on the amp instead to get the desired levels. If your LOC's gain is to high it will clip the signal it sends to the amp, which does BadThings(tm). and might cause the amp to go into protect. A clipped signal will also make your bass boomy and distorted.

Socket7- I will set it the way you say. I understand what you're saying, but again, why would it clip the rest of my audio and not just the sub?
That's why I thought it would be ground/power related.
Is it possible that setting the gains too high on the LOC is demanding too much from the stock bose amp, and it just cuts out? I tapped my LOC connections between the stock bose amp and the speakers, rather than between the bose amp and the head unit.
Maybe what you said will work out. I'll start there and post what I get. Thank you much.

Okay, so this morning I decided to try what socket7 said. I turned down the gains on the LOC to almost nothing, and moved the gain up a lil bit on the amp. Then, I adjusted the "Filter" which I think is what he was referring to by "Crossover" because it does have a on/off switch and I set it to about 80hz. I turned volume up a bit, sounds pretty good.... But the problem still exists... I turned the volume up to 28 on the head unit, and all the sound just went out for just a second then came back on, after a couple more hits of bass, it clipped out again.
I went in turned the gain on the amp down a bit, and just kinda tweaked the "filter" down a little, and it doesn't clip out the sound...but it doesn't hit as hard as I know it could...
Again...why would it clip out the rest of my audio like that?
This is really buggin me :(
Stock amp goes to stock speakers
Aftermarket amp goes to aftermarket sub
Everything clips out...
That's why I keep thinking power/ground
Can somebody enlighten me?

*At high volume, some of the interior lights dim down to the bass.

Thanks for all the help so far guys. Friendly place this is...

Oh, it's all the audio cutting, not just the bass? This could be something entirely different. What channels are connected to the LOC? It may be that the LOC is loading the stereo down too much. Or it may be that the amp is pulling down your system voltage enough to make the stereo amp cut out. Where is the power connected to? Battery? Does it skip on all sources (FM and CD?)
I wouldn't recommend running loud for a while, as you may be damaging something. If the LOC is loading down the stereo too much you may damage it. If your amp is pulling down your electrical system, you may already have a problem with your alternator, or just a bad connection.

The left and right rear speakers are connected to the LOC after the bose amp and before the speakers. They're good solid connections. Gains are currently like 10%
The amp is being powered from the battery.
Yes it skips on all sources.
I will do another run through all connections tomarrow after work and be sure to bring my meter back with me too. It's too frosty in the garage right now.
I guess in any case I'm just hoping my alt. isn't hurt, or my bose amp for that matter. But thanks for your contribution skrubol.
Ill let you guys know what I find.
Thanks again.

If you've tapped after the amp, it shouldn't be a problem with loading down the outputs. The front speakers should still work even if the rear amp had a problem.
I don't really think it would be an alternator problem (though it's possible,) because if that were the case, I can't imagine this would be your indication. The radio should still be able to run even when the engine isn't running. If you've got a high-end multimeter or access to a scope I'd try doing a min/max or plot of the system voltage (taken at the battery or maybe something that's fused, like the cigarette adapter,) with the tunes playing loudly to see if the voltage is dipping that much.

I can't think of any reason for all the sound to cut out. Just the sub sure, but not the stock system too. A bad LOC maybe? :dunno:

A bad ground might cause a voltage drop big enough to cause problems, but I'm really not sure. It might be time to cut your losses and pay a shop to spend an hour taking a look at it.

My bet is the LOC and how it is connected. Disconnect the LOC and the LOC only and retest. If the problem goes away, you know where to start looking.

Forbidden comes through with proper trouble shooting procedure. :)

You mention the LOC is connected to the left and right rear speakers. This is a 2 channel LOC then? Are you sure you don't have the the left positive connected to the right negative signal or something? Not sure what that would do, but nothing good could come of it.

You want me to disconnect the LOC and test with just the stock stereo running?
Yes it's a 2-channel LOC, I'm almost positive I have it hooked up to the correct +/- on both speakers.
I'll go over it one more time. But the connections should be good.
After that I'm going to run an 8 gauge ground wire from the amp to the batt along the outside of my car and see if there's any improvement.
Yeah, I'm kinda to the point where I may just take it in to a shop, I just don't know where I'd take it... Just an automotive shop? I doubt bestbuy is gna wanna mess around with used equipment. The local Tweeter went out of business...
Let me know guys. Thank you so much for all your advice so far. I feel like an idiot, I always considered this stuff somewhat simple... :(

Don't feel bad. Electricity is mysterious, and quality audio is an art form. It's always simple until you go out and do it. It's taken over a year to get my system to a point where I'm relatively satisfied with it, and I still haven't finished cleaning up the trunk properly. These things take time (especially if you're lazy like me).

There is probably a local car audio specialty shop near you. Finding a reputable one is the trick.

The Better Business Bureau, is a good place to start. http://www.bbb.org/ . I know I saw the local car audio shop I visit is a member, and they do a fantastic job.

It is only a 5 day roadtrip and 1 ferry ride to see me........


PS.... BC Ferries suck arse....

Hehe, thanks for the tips guys. I'm gonna check out the BBB website in a minute.

Problem with disconnecting the LOC is that it takes the sub out of the equation entirely, so, assuming the problem goes away, he still won't know if it's power, signal, or possibly vibration.

But at the same time it eliminates the possibility of the main amp or HU being bad. The best way to troubleshoot is to eliminate what it couldn't be first. The more things you verify as working properly, the fewer places you have to look for problems.

I want to know how this turns out. I'm very curious to see what the problem is.

Well here's what I know....
It IS somehow AMP/LOC related, because I disconnected the LOC, pumped up the stereo to max. volume and no problems at all...
The LOC was wired correctly... Re-wired and pumped it up, back to the problem... :(
So before I decide to take it to a shop, I'm going to run a temporary ground to the battery out side of the car, just to see if there's improvement, I don't know if this will rule out the ground, but it might shed some light if the problem goes away...
The LOC is an 2 channel AXXESS that I bought from best buy (the more expensive one)
um...what else can I throw out there...?
I guess a high end multimeter and some numbers would help you guys out, but unfortunately I forgot my meter at work again, although i'm not supposed to take tools home anyway.

Thanks for everything, you guys are awesome

I'd eat my hat if it was anything other then a problem with the LOC with the information you've given us.

Another thing to do would be to test the amp and sub combo from an external source like an iPod. Take a headphone jack to RCA cable, plug your music player in one end, the amp to the other, then crank the volume up, then slowly bring up the gain and see how hard it will thump without distorting or cutting out.

I think david navone sells some quality LOC's that people here have used with good results. I'm not to familiar with them though. I'm currently using a JL cleansweep and audiocontrol DQS to get the levels right from the head unit before going into the amp. It would be quite a bit of overkill for a setup like yours. Hell, it might even be overkill for my setup.

Also... I don't know if this would effect anything, but I've had the LOC grounded at the same spot as the AMP... I'm gonna ground it somwhere else before I try running my ground to the batt. Remember I'm just doing this to help with the "trial" part of the process.
I'm gonna try to rule out as many things as I can like you said...
Keep in mind guys, I work 2 jobs and it's freezing out. I apologize if this project seems really drawn out. If I drove this car daily, it'd be done by now or I woulda pulled the whole thing out and said screw it. But since it's hibernating for the winter, I'm not gonna beat myself up to come to a fast conclusion.
That said, I still probably would have given up a long time ago if it weren't for your guys' support.

I really like the Ipod Idea, if only I can find my Headphone-Rca adapter... That would rule out the LOC portion, yeah? Stock stereo only works good, and if the amp/sub run good w/ext. source it must be the LOC right? We shall see :) Thanks

Still haven't tried using the external source. However, when I got home from work today, I ran a ground from the amp to the battery real quick. I have like a 30ft length of 8 gauge that I used, I coulda made it a little shorter, but I just wanted a quick test and just ran it around the outside of my car. Still made sure the connections were solid.
Results... Problem still exists, although seems as though it helped a bit with the dimming of my interior lights, I really only notice it on my door lights. I haven't tried turning the other lights on but I'm sure they dim to the music too.

So... Hm.. I think I may order one of those LOCs from David Navone.

Also I'm going to upgrade my grounding system. Same thing as the "Big 3" right? Just hits more ground points than just the 3? I was thinking I'd do it myself with my own materials going by the DIY thread. I feel confident in tackling this upgrade.
Except I thought with the big 3, you upgrade the positive post of the alternator to the battery, as well as the alernators (block) chassis ground, and battery's chassis ground... that doesn't seem to be the case in the grounding kits or in the DIY thread. Maybe that's the difference between the "Big 3" and a "Grounding Kit" Anybody know?

Anyways, I figure with a LOC that's been a success to others, an improved current flow, I figure I have to break this wall of mine.

For now, I'm going consider amp ground to battery unnecessary seeing how I got very little if any improvements.

I know there's a lot of mixed opinions about the grounding kit upgrade, but years ago my dad upgraded the "Big 3" in my mx-6 and I got a world of difference. Even before my system I noticed a lot of improvements from idle, throttle response, starting, headlights a lot better (mx6's have crappy headlights) to all sorts of things. So I'm a believer in this upgrade.
In the 8, if anything, I hope to atleast get a little smoother of an Idle. Mine sometimes kinda "flutters" in the rpms, and can kinda hear a slight "puff" come from the exhaust at idle. It's really not noticable unless you've put 2 n 2 together enough times driving.

*I heard/read some Rx8s actually have terrible factory grounds... So I'm kinda set on the plan.

I'm going to order the LOC and some High-end terminals for the grounding set up when I get my tax return, cause I know I'm gonna want to order more stuff for the hell of it.
I figure that isn't going to show up in my account for probably another week or so.

So should I just continue on to this thread when all that goes down, or should I start a new thread?? This thread can use a new "Title" as is... LOL, I think I'm way past what size wire I should use to run to my battery. HEHE
But I figure you guys might atleast want an update when I get to that point.
Thanks again fellas

Some of them do have terrible grounds, and dimming lights can be a sign of one.

There are a few grounding kits people have used here. check them out and get the one you like best.
I've got a few photos of my own up here, http://sites.google.com/site/rensaud...rading-grounds , but unfortunately, i forget who makes it. I think it's a vendor here. It was a bit on the pricey side, but i think it's worth it.

Keep posting about your install here. No need for a new thread. Threads like this can help other people with their own install if they encounter the same problems, so it should be all kept in one place, even if the nature of the problem changes with new evidence :)

Yeah, after going through maybe 5 or 6 different grounding kits, I've decided I might as well do it myself with DIY thread. It doesn't seem difficult and I already have most of the supplies. I'm itchin to get this LOC, it appears to only be like $20? Is that right? The LOC i'm using right now was around $50 if I remember correctly, I'm gonna kick myself if this is the answer to my problem. Which it probably is...

Thanks for everything Socket7, I'll keep the thread updated.

Hello again. It took a while for me to get some time back on the computer and let ya guys know where I'm at with this. I followed the DIY grounding thread, and WOW. Huge difference in a lot of areas of the car...
-Starting the car was almost instant when I turned the key
-Headlights are brighter without a doubt
-Throttle response seems a little more crisp, but that could be the "placebo" deal again.
-The music barely effects the interior lights now, you'd only really notice it if you were lookin for it.
-AND the BEST part....
My stereo no longer cuts out with the subs up! I even turned the gains up much higher than I would normally be comfortable with, and not a single hiccup! :) :) :) :)
I never ordered the LOC from DN, for now I'm okay with this one. Eventually I can see myself upgrading the entire sound system, but that's not going to be for a long time. If I have problems with this LOC in the future, then maybe I'll go back to ordering from DN.
So that's that people!
My only conclusion really, is my car must have came out of the oven with a lousy ground.
Thanks a bunch to those who helped me sort this problem out.

I'll add some pictures of everything I installed (related)...
as soon as I figure out how to post pics, I already took pics of the grounding project.
Still gotta finish tucking everything in inside the trunk and will take pictures of that as well.