Car Audio Central - Ultimate Car Audio Forum and Community

by **_gonz_** » Fri May 05, 2006 7:56 am

Bwcad1 wrote:ok i can take your points into consideration

Also take into consideration that, we do things above and beyond, when we're really trying to do it right.

Theres convienient...
And then theres "optimal".

To say your RCA signal cables have to be on the opposite side of the car from your power cable, is incorrect... in my view and experiences.

To say "the optimum way to run cables is to isolate them" is actually correct. The only part I'd argue with is where and why you'd see any negative effects... because you should'nt see an actual difference either way.

I hope I'm making sense here.
So if we're ripping apart both sides of the car anyhow, and running RCAs down one side, and power down the other is easily doable... ask yourself, why not take the optimum approach?

But if you have a noise problem, I really don't think moving the cables to the opposite side will fix it. If it does actually eliminate the noise, I'd immediately replace that cable, because at that point I'd conclude it's faulty. In essence, the problem being with the cable itself, not it's location.

With home theater for example, people want their power cables away from their RCA cables. Well, at some point, your wires are going to end up crossing over one another... or else, all tucked behind the entertainment system in close proximity to one another anyhow. So end result, it's usually just foolish to worry about a non-existant problem, when with wiring, it's hard to keep things apart, sometimes.

Now when, and if, it really does become a problem, that would be the time to confront it. Fortunately, these days, it really isn't an issue. And it does'nt mean $3,000 interconnect cables are necessary, just decent quality $10-$15 sets will suffice.

by **Robert Wollenberg** » Fri May 05, 2006 7:53 am

I second that. I've seen kids too cheap to buy the fuse and have something short in their trunk. That power wire can burn for quite a while. lol.

by **Bwcad1** » Fri May 05, 2006 7:47 am

exactly thats y i say it should be as close as possile. and i know i always run fusing even in my comp car that .01v or what ever it could be just isnt worth it to me.

by **_gonz_** » Fri May 05, 2006 7:43 am

Bwcad1 wrote:ok i can take your points into consideration but not this one it should be no more than 6 inches i have never seen a battery that you would have to put the fuse 18 inches away thats just crazy talk! lol

You don't Have to....
It's just the maximum allowable length away from the battery for safety. You should get it as close the the battery as you reasonably can.

SPL competitors sometimes use no fuses at all, because god forbid they lose that micro-fraction of a volt!!!

Rather the whole car go up in flames

Someone on CAF got into a heated argument with myself, and another pretty knowledgeable guy, because he was adamant that you never fuse at the battery. Advice like his has gotten people killed.

by **Bwcad1** » Fri May 05, 2006 7:39 am

_gonz_ wrote:As for 18" ... thats the general rule for battery fusing

ok i can take your points into consideration but not this one it should be no more than 6 inches i have never seen a battery that you would have to put the fuse 18 inches away thats just crazy talk! lol

by **_gonz_** » Fri May 05, 2006 7:36 am

Bwcad1 wrote:y take the chance? if you buy cables that are so called sheilded and they dont work you have to pull it out and it it again anyways.

Thats like saying "why take a chance, the JL amp might not work"
If your specs say it's 95% shielded, or specs say it's 500w RMS, then thats what it damn well better be... and it's usually true with a quality company. Go to parts express and look at Dayton's shielded RCA interconnects. Or KnuKonceptz shielded RCA interconnects. Or any other reputable brand.

You will NOT get noise with them. As a matter of fact, it's seriously unlikely to get noise in cheapass scoshe RCAs ran on top of Scoshe power cables. How do I know? My last install was done exactly that way for the sake of convieience... and I had no noise whatsoever. No filters of any type used either.

If you end up with a bad RCA of any brand/quality that has a poor solder job, or a cheap cable with extremely thin conductors, then you will probably run into trouble.... but we don't go to the Dollar Store for interconnects, and defective cables are defective cables, period.

Also don't forget... with electronics as sensitive as they are, and all the sensors and computers in today's cars... we don't have cheap ass electrical systems these days, compared to a 1970s diesel pickup with glow plugs. Regulation of power is improved from what it used to be.

As for 18" ... thats the general rule for battery fusing, while the general rule for grounds is 3'. Short as possible is always the best, all around rule, for wire/cable of any type in any application... from Toslink and SPDIF cables, to Coax, to speaker wires. The shorter the better, always. (exception to that rule is in antenna applications where the cable length and resistance, actually makes up part of the antenna itself)

by **Bwcad1** » Fri May 05, 2006 7:20 am

_gonz_ wrote:Why?
Whatever you've been told, it isn't true... IF your cables are shielded.
Put unshielded speakers near a TV and the screen turns purple. So they always told people keep speakers away from TVs and subwoofers away from computers. Nowadays these things are shielded, and so that rule no longer applies.

y take the chance? if you buy cables that are so called sheilded and they dont work you have to pull it out and it it again anyways.

Where, how, and why... does your 12v power lead have any bass whatsoever? Good quality headunits have extensive power filtering built in. This is one of those "features" that equate to getting what you pay for. Does that mean these high quality SQ decks have no bass response? C'mon now. MYTH, busted.

i thought you were talking about the inline rca noise filters my bad.

As short as possible is the rule.
You can actually run your ground all the way back to the negative battery terminal with no ill effects whatsoever.... but also with no real benefit... and a large expense in unnecessary cable.

there is a benifit only in spl though not much for any other application as kiki has stated many times before most modern day cars have spot welds which only equate to about 4 gage wire. when i went back to the battery my voltage gained .2v. and in spl comps voltage means alot.

by **_gonz_** » Fri May 05, 2006 7:15 am

Bwcad1 wrote:(this is a fundemental no you should never run your rca's on the same side as your power wires its just asking for trouble.)

Why?

Whatever you've been told, it isn't true... IF your cables are shielded.
Put unshielded speakers near a TV and the screen turns purple. So they always told people keep speakers away from TVs and subwoofers away from computers. Nowadays these things are available shielded, and so that rule would no longer apply. Same thing with RCA cables... shielding keeps out noise and interference. You can get RCA cables with 4 different types of shielding, for cheap money. No reason not to buy them.

(i have tried these and they killed my bass response. they were not worth the money and i wouldnt try them again.)

Where, how, and why... does your 12v power lead have any bass whatsoever?

Good quality headunits have extensive power filtering built in. This is one of those "features" that equate to getting what you pay for. Does that mean these high quality SQ decks have no bass response? C'mon now. MYTH, busted.

Using this type of power filter at an AMP is going to be a problem, as you're going to draw more power than the unit is capable of passing comfortably, thereby possibly reducing your amp's headroom. That can result in lower dynamics. Headunits are an entirely different set of rules, as it's not drawing 40 amps worth of current. Noise filters are not meant for amps, but for headunits yes.

(good advice but i always say 18" but thats just me)

As short as possible is the rule.

You can actually run your ground all the way back to the negative battery terminal with no ill effects whatsoever.... but also with no real benefit... and a large expense in unnecessary cable.

by **Bwcad1** » Fri May 05, 2006 7:02 am

_gonz_ wrote:RCA cables should be quality, shielded cable. You want heavy shielding because thats what blocks noise (RFI).

If you have quality cable, running them right alongside the power cables should'nt matter one bit. Never has in my experiences.

(this is a fundemental no you should never run your rca's on the same side as your power wires its just asking for trouble.)

The headunit... could simply have poor power filtering internally. You can get a noise filter, which connects to the pos/neg power input from the car wiring harness. They'll usually knock out alternator interference... and don't cause any problems. Its just a filter on the 12v line.

(i have tried these and they killed my bass response. they were not worth the money and i wouldnt try them again.)

Supressor type spark plug cables are usually worth the investment.
Make sure your amps are both grounded to the same spot. Sounds like you do your setup the same as I, where amp grounds go into a block, and only one cable out > to single grounding point. If so, as long as the grounding point is to the chassis, clean, and paint free... should be solid.
Is your ground run less than 3ft overall?

(good advice but i always say 18" but thats just me)

Can you shorten it, and perhaps try another location to ground to?
These are all the factors I'd be looking at... and over the years have been the tricks I've used to clean up any noise issues I've ever come across.

by **Darthness** » Fri May 05, 2006 6:50 am

overal it should be less than three feet. the 1/0 that goes from the chasis to the ground block probably a little udner a foot... i'm not changing my ground location though. i've already came too close to my gas tank for my liking.

Car Audio Central - Ultimate Car Audio Forum and Community

Teh Noise

Post a reply

Expand view Topic review: Teh Noise