Inducted Interferance, etc.

[Lyle's GTP]

Hey stereo guys. I need to know what the minimum safe distance is when running signal wires near/parallel to power wires.

Also when mounting a 2-way component set in the back dash. What is the best configuration? Should both speakers be fired toward the glass or should the tweeter be directed toward the listening area. Keep in mind this is with best sound quality in mind.

Last thing, how will grill cloth work for covering a fan? Will it allow enough air flow or does it have too much resistance?

Thanks in advance.

PS. Shouldn't their be an electrical section on the forum main menu? It could cover ignition, chassis wiring, stereos, electrical accessories, alternators and batteries. Just a thought.

Lyle

[bszopi]

RE: Inducted Interferance, etc.

It depends on what type of signal wires you are running. Ideally, opposite sides of the car are always best, but never really easiest unless you have your car torn apart. If you are running twisted pair signal wires, then you can probably get by with the cables relatively close to the power cables. I've done it before with no real noise pickup. And at the same time, I've had them on opposite sides and had noise. So its more than an experimenting thing than anything. But the further away, the better.

Again, its more of an experimenting thing, mainly because it really depends on the dispersion of the speakers. Normally, its best to have the tweeters pointed directly back and the mids pointed toward the center of the roof. With dsah speakers, this can be quite hard without blocking the speakers, or physically fitting them in. I would hook them up and try them both ways. I would probably try to point them toward the rear of the car if possible and see how it sounds (should have a wider soundstage). Then try it hitting the glass. You are going to get more mixing that way, but it may sound better. Just depends...

As far as the speaker cloth on the fan... You should be just fine. I've done it several times before. If its visible, you may just have to clean it every now and again, because the cloth will hold dust quite well.

[Juglenaut]

RE: Inducted Interferance, etc.

You can also filter the noise to ground, and you can use a simple passive filter on the amps power terminals. Want to know more PM me. My e-mail now picks up PM alerts.

"Twisted pair" or baseT acts like a passive filter.

Often most stray inductance is around 2kHz to as high as a human can hear because of the alt, however most times the bandwidth frequency is tight.

In extreme cases an active filter can be used set up as a band-pass filter or a noise rejection set-up to a resistive ground or dirty ground so to speak, running the noise though a resistor network to ground controlled buy a tone decoder(s) and a data selector to set a path. The resistors will help dissipate the noise before entering the ground. A resistor in aspect to ground is 'dirty' only passively.

Even though a signal wire may be twisted that it only for it own inductance or interferance feed into the line through its source, placing it parallel to a power source wire will induct some noise depending on how big the source is and how good of shielding it has even then shielding is shielding, double shielded wire has no more going for it then cost.

See it like this; if 50 amps is going though a 8gauge wire and the signal wire is right next to it, the magnetic flux is rather larger. 8ga wire has less free valence electrons thus less capacity so the flux is large and extends upto 5 times it radius the energy has to have somewhere to go so it is lost to inductance (resistance) and some times to capacitance. Then if you have 50amps on a 4 gauge wire the flux drops because the cable is not even close to being fully energized, the 4ga cable also has more free valence electrons thus more capacity and less resistance which is key here, as a given cable gets longer the more resistance, this is where noise enters the equation. Good fine braided large gauge power wire comes into play at a point.

A clean ground and a large power wire should not cause any noise no matter where the signal is, this depends on the amps you need to deliver to the amplifiers however. If you need to cross a power wire lap it over the powere wire at 90 degrees.

If you plan on running a ground source to the battery always use a gauge larger then the power source. The cleanest ground is at the battery not the frame.

[Lyle's GTP]

RE: Inducted Interferance, etc.

Well, in my Grand Prix, there are a ton of factory wires running on both sides of the car. I am running my main system power opposite of course. I am also running my speaker and signal wires along the roof instead of the froor. My signal wires are top notch, shielded, silver plated OFC conductor, twisted pair, split-tip, platinum plated contacts, silver soldered and the bag of chips.... $100 bucks each. As far as signal voltage, I am running an 8-volt, 55 ohm preout to my EQ's which are good for 10 volts of output.

On the power side: I've got a 170 amp alternator connected to an Optima Yellow Top (primary) via 2-awg, 2000 strand OFC. From the primary I'm going to a 200 amp battery regualor/isolator via 0-awg, 4000 strand OFC. From that to a Lightning Audio SBX-1500 AGM battery (secondary) via the same 0-awg. From that to my amps via 4-awg, 1000 strand OFC. Along the way to my sub amp I have two 1 farad 24v capacitors in parallel.

I have the whole interior pulled and have relocated most of the factor wiring that is in my way, but I can't get all of it. I have narrowed it down to 3 trouble spots. The first one I can cross at 90 degrees, but it is speaker level, so I'm not too worried. The other I have to run parallel for about 10 inches and it is signal level. But it is a small interior light that is only has power when the door is open or if somebody flips the switch. The last one would be some wiring I have to run and the signal/speaker wires will run parallel to it about 12-8 inches apart for about 2 feet. These wires though are 16 guage and are carrying only enough current to activate a relay.

Oh, and just for good measure I pulled the antenna wire out of the huge factory wire run, and ran it by it's self.

I've got a ton of cash invested in this bitch, so I don't want any cheesy engine whine. I wish a company would hurry up and build balanced equipment, Eclipse started with it but only build one head unit and sub amp capable of it. But dropped it soon after. Now their new line has nothing Balanced in it. Whores.

Let me know if anything should be upgraded or changed.

Thanks

Lyle

[bszopi]

RE: Inducted Interferance, etc.

Umm... AudioControl has balanced line stuff. And I think you are worrying too much. If you start worrying about getting noise inducted from wires such as the roof light, you are worrying too much.

[Lyle's GTP]

RE: Inducted Interferance, etc.

Fair enough. As far as AudioControl goes, nobody sells it around here. It seems that any time I build a system like this I end up with some sort of noise. So, this time I'm not fucking around.

Thanks for the input.

Lyle

[Guest]

RE: Inducted Interferance, etc.

I always run the signal down the passenger side and power down the driver side. Part of that has to do with running the signal wires past the steering column/pedals, or rather NOT doing that. Also in most cars there are more wires running along teh driver side than passenger side.

How to install the rear components with best SQ in mind? No tweeters. I'm VERY serious about this. Use only the mids. Reason being if you do any studies on a venue, say a theater or concert hall, most of teh high frequencies will be absorbed or not reflected due to thier wave forms being so short, so they don't traval as far as lower frequencies, and will seem attentuated from behind in comparison to teh lower frequencies. Also the natural roll-off of high frequencies of an average mid, is about ideal to momic this effect.

Depends on the cloth. Myself I try and place the fan so the opening to the fan will not be viewed, say behind a trim panel, so that you don't get that ring of dust on teh grill cloth.

[bszopi]

RE: Inducted Interferance, etc.

Damn, I didn't even noticed it said back dash. Yeah, no tweeters. Actually, I prefer no rear speakers at all, but many people will disagree with me there. The less rear fill you have, the more natural it will sound. Leave rear speakers to home surround sound setups where they are actually utilized correctly.

[Guest]

Re: RE: Inducted Interferance, etc.

Damn, I didn't even noticed it said back dash. Yeah, no tweeters. Actually, I prefer no rear speakers at all, but many people will disagree with me there. The less rear fill you have, the more natural it will sound. Leave rear speakers to home surround sound setups where they are actually utilized correctly.

Yeah I too prefer no rear speakers, in most cars. but sometimes a little fill can be good.
About the only time I suggest rears is when a Surround system is being installed, with DVD and screens.

[Lyle's GTP]

RE: Re: RE: Inducted Interferance, etc.

Well, I got them. So I might as well use them.

Lyle

[IXLR8]

www.splbassx.com ...................Go there awesome bunch of guys

[Lyle's GTP]

So, I figure I will install the components faceing up toward the rear window. As far as loosing the tweeter, I'm not going to go that route. I will see what I can do with my 1/3rd octave EQ. I haven't decided if I'm going to compete yet, but anything is possible.

I was looking at my wiring set-up today, and I think it's pretty good. As of right now I have no parallel contact with any power wires.

Lyle

[Guest]

So, I figure I will install the components faceing up toward the rear window. As far as loosing the tweeter, I'm not going to go that route. I will see what I can do with my 1/3rd octave EQ. I haven't decided if I'm going to compete yet, but anything is possible.

I was looking at my wiring set-up today, and I think it's pretty good. As of right now I have no parallel contact with any power wires.

Lyle

If you are going to compete in SQ, then you WILL loose the tweets, maybe even the entire rear fill. IASCA especially hates to hear rear speakers.

You made me cringe when you mentioned using teh 1/3 octave EQs to "see what you can do", with a known problem with the staging to start with. EQs cause other problems like Phase shifts, especially when used to make major adjustments.

[Lyle's GTP]

Not using the EQ for major adjustments. I wouldn't consider using the rears in SQ. Just for my personal amusement. I'm actaully in the works of trying to get my hands on an Eclipse Line Source component set. It is a 3-way set up but the midrange is a 2"x6" flat planar speaker. Absolutely phenominal imaging from those.

Lyle

[bszopi]

The only thing I have found good about 1/3 octave EQs (and I have used them in competition before) is getting a flat frequency response for that portion of the competition. I've actually seen people use 2 EQTs and and EQL together, using the EQL as the main tuning module for SQ, then using the EQTs to flatten the curve. They have the EQTs on ONLY for the freq test, then turn them off for the rest of the competition. But unless you have a meter (yeah, I still have an AudioControl 3050 RTA), trying to tune with 1/3 octave EQs are probably going to end you up with a terrible curve.