Car Audio Speaker Wiring

[1972ChevyCheyenne]

Currently I am working on installing a head unit in the glovebox on my 72 truck. I plan on running am amp sometime under the seat, but right now I want to get all the wiring done, expect the power feed for the amp. The head unit is a panasonic cq-c1401u. I plan on using 16 gauge speaker wire from where the amp will be to where the speakers are. Anyway my question is what type of wire do I need to run from the headunit to where the amp will be. Can I use 18 guage 4 strand (like the tail light wire) automotive, or will that cause speaker noise if they are ran in the same channel? I wasn't thinking far enough ahead to put them in before the carpet that is now glued down Thanks for any help.

[djracer]

16 or 18 is large enough for speaker wires! You will need 1 or 2 rca cbles and a remote wire ran from the headunit to the amp along with a decent gauge power wire! are you planning on running the speaker off the radio now and an amp later? P.m. if you need any help I've been in the biz 20yrs!

[bagged74]

werd, hes correct. Ive been in the biz for a long time too

[piecesparts]

The trigger wire for the amp can be a 16 gauge wire. This is the one that is run from the back of the radio unit to the amp to turn it on when you turn the radio on. There are two ways to wire the amp from the radio for sound. The first is the best (cleaner sounding signal); it is by using RCA cables that send a low power radio signal to the amp. If you only have right and left to worry about then there will only be two. If you are going for front and rear seperation and the right and left sound, then there will be four cables. Hopefully the radio is set up for this.
The second way is MOST radio/head units have a set of higher power speaker wiring connections, along with the RCA connections. This is usually around 25 watts and can be connected to another amp. However, this may created a distorted sound when you try to increase the power the amp is capable of generating. The signal is confused by the power that the radio unit is sending out. This is not recommended.

Most head units have a wiring diagram in the back of the owners book that shows the simplicity of how this can be hooked up and what color wire goes where.

The power wire for the amp needs to come from the battery through a fuse or circuit breaker and connect to the amp directly. It needs to be whatever the recommended size that the owners manual has. Most are around 10 gauge or 8 gauge. The fuse needs to be just after leaving the battery---so that if the wire were to rub through and "go to ground" your truck would not burn up. Where ever you go through the firewall or sheetmetal, drill the hole big enough to use a good quality rubber grommet for the wire to feed through. Safety is first. I personally run all of my stereo equipment ground wires to ONE point (radio, amps, or accessories) so that there is no ground static build-up in my sound. That will be your choice, most people ground to a clean sheetmetal point that uses the frame to feedback to the truck battery, at different points in the body.

[shifty]

Everything that piecesparts just stated is 100% on point (great post, man!)

I used to work at an install shop in high school. Always use a dedicated power wire for your amps. 10 gauge power wire is sufficient - do not run it on the outside of the car. Perfect installation would be like this: run a 10gauge wire from the battery, through the firewall (be sure to use a rubber grommit! Greenlee knockout punches are great for making perfect holes in a firewall) and back to the amp. Be sure to: 1) debur your hole and use a rubber grommit to keep your wire from getting cut and grounded out and 2) Be sure to use a circuit breaker or fuse WITHIN 18" FROM THE BATTERY - this is super important just incase the power wire DOES short out somewhere (unless you like your car burning down ).

With that said, you'll run your power wire from the batter to the amplifier - don't tap off of the radio power wire. Run a stranded 16-18 gauge wire from your "remote turn on" or "power antenna" lead on the back of the stereo back to the amplifier's "turn on" power feed. This will make sure the amp is only turned on when the radio is on - use this unless you like your battery dying.

Last, be sure to ground the amp properly unless you like lots of ground noise (alternatore whine, etc.). strip any metal from the place it's contacting. Mount to a shock/strut tower or something that attaches to the frame, not just to a body panel.

There are two basic types of signals you need to understand: "amplified" or "speaker level" signal - this is the powered signal that your radio puts out to the speakers directly using the supplied speaker cables. then you have "non amplified" or "line level" or "low level" signals. This signal has little to no power and is what you want to feed into an amplifier - you should have RCA outputs on the back of your stereo that will put out this low level signal. If not, there is a company called "PAC" that sells line-level converters, they will turn a speaker level output into an RCA output. I wish it was as easy as just splicing an RCA into a speaker wire, but it ain't . I can link you up to one of these at Crutchfield if you want to get one cheap.

You should use the RCA outputs on the back of your reveiver if possible - assuming yours has them. It is not suggested to run a "speaker level" signal into your amplifier or you'll get the distortion spoken about above. You should try to always run RCA's where possible. If your amplifier has a "speaker input" on it, I guess you could go ahead and use it. I still wouldn't recommend it. Most of your better equipment won't have features like this.

I suggest 14 gauge wiring as a minimum for any speakers that are being powered by an external amp. Sure, you can use some chintzy ass 18 gauge wire - it will work, but your overall stereo system is only as strong as its weakest link - so, why would you buy an external amplifier to increase power only to choke out the sound using cheap ass wire? Wire should be your biggest expense consideration when piecing together any sound system. Buy good cables - good power wire, good RCA's, good speaker wire, good ground wire. In most cases, going big is your best bet.

For reference, one 10 gauge power wire is suggested for each amplifier. If you need to run two amps, but only want to run one power wire, you can buy trunk-mount power distribution blocks at your local stereo shop. For two amps, run a single 8 or 6 gauge wire to the location the amps will be and split it into two ten gauge wires using a distribution block - the 6 or 8 guage will carry enough power to allow you to cleanly split the power equally between both amps with no loss (if you use one 10 gauge and split it into two ten gauge wires, you're only getting half the power to each wire!)

Lastly, never run RCA (low level or line level) signal wires anywhere near a power wire. Try to keep your speaker wires away from your power wires. For example, never run your RCA's or speaker wires bundled up with your amplifier power wire. This is a big no-no, you will be able to hear electrical noise if you do things like this. Try to run all of your power wires down one side of the car and all of the speaker/signal wires down the other side.

[pat]

Great thread

[Hoods69BadBowTie]

Yeah, Shifty and pieceparts described it in alot better detail and wording then I could have. Some good info in there posts too.
-Later

[djracer]

I am familiar with your panasonic headunit I know it has rca's so I didn't mention running a high to low convertor! never I quote "never hook up any amp with speaker wire inputs" end quote! the size of the power wire is determined by the size of the amp and the distance of the run don't just run a wire without making sure its big enough! I challenge anyone to be able to hear the difference in speaker wire size unless it an extremely long run or the wire get smaller than 18ga! Typically I run everthing 16 but that's just a preference! if you tell me what size fuse or fuses are in your amp I'll recommend a proper power wire! your radio has an amp turn on wire some don't and they must use the only option which is power antenna wire! If you use the power antenna wire your amp will turn off as soon as you put a cd in the player "NOT GOOD" it is a good idea to keep power away from the rest of your cable but if you are using a modern amplifier it may not be an absolute necessity! If you have any questions feel free to pm or ask here! one more thing it makes no difference what gauge your remote wire is period! The amount of current required to turn onan amp will not even light a bulb type test light! therefore it can be tiny!

Kevin

[panhandler62]

I'll just chip in a temperance comment.

Unless you are investing thousands of $$$ and using very high power amps and speakers; high buck speaker cable is not required. 16 gauge generic wire is quite sufficient.

Don't chintz on terminals though. All connections should be soldered or use decent quality solderless connectors -- no twisty-ties!

As for power.. not much more to be said. I run two small amps (35rms x 2 and a bridged 80rms for my sub.) I ran 8 gauge to a barrier strip and 10 gauge cable to each amp. That's probably overkill, but I really hate electrical fires.

[bodydropped]

all my truck is ran off of 14 gauage wiring i got bored and redid the whole truck because i got tired of the orginal wires shorten out im runnin the amp turn on wire from a amp kit but im ruinnin memphis car audio rcas from my head unit to the line driver and from the line driver to the amp

[1972ChevyCheyenne]

Thanks for the help guys! I was going about it the wrong way (the not reconmended way). I see where the RCA jacks are now so i'll get three cables and run them for the Sub and front and rear speakers. Not that a sub will likely fit though. Can I run the ground wire for the headunit in the same bundle as the RCA wires if it is grounded at each end. I figure doing this should compensate for and resistance in the metal between the grounds for the amp and headunit, therefore making basically it the same ground point. My power for the head unit comes in through an 8 gauge and then I will be building a fuseblock to feed the headunit and a couple other small lighting loads.

Also it was said that the power wire for the amp should be ran inside the cab. What would be wrong about running it along the frame it I get it to where the amp will be? I have yet to buy an amp, so i don't know what gauge I'll need.

The fuse at the power source is a good idea, I never thought of one there.

I have nothing conected right to the battery all my wires go to a juction block. and the through a 14 gauge fusible link to the battery. This is okay to wire everything to that junction box right?

I think I am on the right track now. Thanks for all the help.


BTW I found my wiring instructions, again. The weren't with the rest of my liturature on the headunit. I put them with the headunit so I'd have them when I was installing it. Who would have thought they would be there were you'd need them.

[djracer]

Jamie
Their is no problem running the power wire along the frame just be sure to use a grommet where you come into the cab! I would use a 8ga wire if you want to go ahead and run the power now with a inline maxi fuse close to the battery! If I was to ground the headunit in the rear you could run this ground with the rca's but I would only ground it up front or in the rear but not both! I use panasonic headunits all the time and rarely have any noise! I used to ground my headunits in the rear but I don't anymore!

Your junction box should be fine for your other acc.

[shifty]

I'll agree with djracer - I intended to put 14-16 gauge speaker wire in my post, but edited it out somehow (Normally if you buy the wire in bulk at the store, it's like t-shirts from Hanes or Fruit of the Loom, it's packaged as 14-16 gauge or 18-20 gauge...), Believe it or not, you can get pretty decent wire from Sears in a spool of 50ft for 10-15 bucks if I remember right. Circuit City and other name brand stores charge out the butt for it.

The suggestion above about not skimping on connectors is also great. USE A GOOD PAIR OF CRIMPERS!! Do not use crappy ones like this: http://www.installer.com/photos/crimpersb.jpg --- go out and spend a couple bucks on a good pair like this: http://www.qsradio.com/Regular%20Crimp%20Tool.jpg --- best purchase you'll ever make...Home Depot and other hardware stores sell them. You'll save time on soldering, it's an easy way to do "almsot the best". Not many stereo shops solder these days, but solder and shrink wrap is king!

As for running the power cable along the frame, this is not suggested - I say this because this wire is thick, it is a direct power line from the battery and the longer your wire runs outside the cab, the more chance it has to short out all that power -also - when exposed to the world, you risk corrosion/nicks/oil and heat absorption/other damage to the wire. Most professional fine multi-strand power wire sheathing is not made to handle being outside like that. Generally, inside the engine bay is portected from most elements like water, oil (unless your engine is in seriously bad repair) and heat (run along the upper fender well to avoid heat). If you stick inside there and run through the firewall from the battery, you only have maybe 3' of wire exposed to the elements. If you must run along the frame, keep away from all moving parts and use a wire that is oil/heat/gasoline/water resistant to preven copper corrosion or breakdown/hardening/deterioration of the plastic wire sheath.

The previous comment about Power Antenna leads is typically correct on most modern stereos. Your remote turn-on lead is normally blue in color if there is both a power antenna and a remote turn on lead. I've seen some radios that have only one lead (older ones) and it stays on all the time as long as the radio has power - it works as a power antenna lead or remote turn on.

IF you only have one RCA output? Get a crossover, small equalizer or get a quality splitter from your local stereo shop - run one RCA cable to the amps area and run into the EQ or crossover - but if you do this, you can't fade front-to-back on your stereo Some quality amplifiers come with a "piggyback" lead that will let you jump the signal to another amp from the first. This is really convenient way to reduce runs. Look at yours before proceeding to see if this is an option (but - again - you can only fade if you use 2 or more RCA cables from diff't RCA jacks!!). Ignore all of this Paragraph if you have multiple RCA outputs on your stereo.

Good RCA cables will come bundled with a remote turn on lead already attached. It's a thin wire. Go to the wiring section at Best Buy or Circuit City - look at theirs - you'll see a pair with this extra wire, I'd almost gaurantee it.

Your wiring to the junction box sounds fine. 14 gauge, through a breaker/fuse within a foot and a half of the battery, back to a distro block. I still suggest using 10 gauge wires for each amp if it's pushing 50w or more - really, I guess it depends on what the amp is wired with inside the guts of it. If you open the bottom cover and the power terminal is wired to the amp circuit board with 14 gauge wire, there's not much point in using something larger - again, you'll only get as much power as your smallest wire will hold. But if you're doing stuff like I do, you need something beefy Example of my old truck's install:

0 gauge power wire:
http://shifty.org/pics/truck/stereo_...l/IMG_0975.jpg

Amps and capacitor:
http://shifty.org/pics/truck/stereo_...l/IMG_0981.jpg

That's only ~$1000 in amps and wire.



If you find your amps are dimming your headlights, come back and post; I have solutions (capacitors).

One last note: If you're running 10 gauge wire, use a 10 gauge fusible link, not a 14 gauge. Again - a chain is only as strong as its weakest link. In theory, by inserting a 14 gauge link in a 10 gauge wire run, your bottleneck is at the 14 gauge wire.

[djracer]

Jamie your remote wire is blue with a white stripe. Pm me if you need help on an amp! of course you will have to have a 4 channel if you want to fade! Quality crimpers like shifty showed are a must on an electrical work period. they have some like that cheap at harbor freight!

Kevin

[1972ChevyCheyenne]

Thank for the help guys. I know what wire you are talking about for the remote switch. I am now on the road to a reasonable sound system. Now atleast I can listen to music as I go nowhere. Maybe in late April my truck will be on the road. As for an amp maybe early spring I make a selection. Thanks again.

[shifty]

I've had great experiences with the JL Audio amps you see pictured in my post above. A few tips:

Don't buy generic equipment.

You get what you pay for.

Most importantly, aim for upgradability! To start your system, think. For example, for your first amp, I suggest buying a 4 channel amplifier that is capable of running in 2 channel, 3 channel or 4 channel mode. Something with a power rating like ... 4x35w, 4x50w or 4x75w.

Thinking about this in greater detail, with this single 4-channel amplifier, you can run your mids and highs (front L/R) off of two channels, then "bridge" channels 3 and 4 to make a single (mono/bridged) channel so you can power your subwoofer (let me know if you need more explanation on what this means.). Basically, with a 4-channel amp, if it will handle 4/3/2 channels that is rated at 4x50w, you can:

Do 4 channels at 50w each: this amp can push front L/R and rear L/R, so you can run all mids and highs in your vehicle off of it - each channel will get 50w each. Doesn't seem like much wattage, but it actually is...remember, your radio uses cheap, light, small equipment that won't overheat - so in reality, 50w from an amp is in reality 10x more stable/powerful/capable than 50w from a radio.

Do 3 channels, 2 @ 50w and one at 100w or more: run front L/R mids at 50w each (or all mids and highs, if wired correctly) and bridge the other 2 channels to make one subwoofer channel.

Do 2 channels: Run both channels in bridged mode and either push two subwoofers indepenednetly or run your front L/R or rear L/R off this one amp.

So, using this configuration you start out with one amp to power your highs and mids. It will allow you to run your whole system for a while until you can afford to buy a dedicated subwoofer or a second mids/highs amplifier. Later, you can buy another amp to add to your system and move some load off of the first amp(s). It's very economical and will keep you sane with good power in the meantime.

If I were you, I would first buy a 4 channel amp - push front L/R and a single subwoofer with it. Second, buy another 2 or 4 channel amp - take the first amp, power all my mids and highs off of it, then use the new one to drive my subwoofer. Last, buy one final 1, 2 or 4 channel amp, using the previous two to push my mids and highs, then the new one to push my subwoofer.
Finally, when you have all your amps, think about upgrading speakers.

I would try to stagger your rear/front wattage in the end. So, for example, use a 4x35w amp for your rear mids/highs and a 4x50w amp for the front mids/highs.


Two last things you need to know about wiring -

1) When I say "wired correctly" above, you need to understand the two basic ways to wire up speakers: in Parallel and in Series. I would explain this to you, but it is so perfectly described with pictures at this one website that it would be stupid for me to try Here's the link: http://www.bcae1.com/spkrmlti.htm --- Check it out.

2) Depending on how you wire your speakers (based on #1 above), the ohm ratings on your speakers are very important. The higher the ohm rating, the less resistance it will give the amplifier. The lower the ohms, the higher resistance it will give the amp. Basically, by wiring (2) speakers in series, you can decrease the resistance (load) on your amp and reduce the wattage your amp will push into the speakers. By wiring in parallel, you can increase the resistance (load) on the amplifier and it will push more wattage into the speakers.

To clarify on those numbers, say you buy (2) 4ohm speakers. If you wire them together in parallel, you have reduced the resistance the amplifier will see down to 2ohms! That means a 50w amplifier will actually push something closer to 100w (total) into those two speakers because of the lower ohm rating! If you wire them in Series, the amplifier will see that as a 8ohm load and will actively only push ~25w total into them. That's only 12.5w per speaker, which is crap.

You can do some neat things with this - like get a dual-voicecoil subwoofer...that is @ 4ohms per voice coil. Well, wire them in parallel using a 50w amp and you can push 100w into them...it's definitely a good deal - you just upped the wattage you're pushing into a single speaker by almost double!

Your amplifier will say "2 ohm stable" or "1 ohm stable" in the specs. This will let you know how low of an impedance (resistance/load) it can handle. If you go below that level, the amp can overheat and will start "clipping" (cutting out). This is a quick way to blow your speakers

If anyone needs more clarification on this stuff, ask, I will try to explain.

[GoobersBlueBurban]

I know most people like the convenience of having the amp come on with the cd player, but I like to have my amp(s) on a switch. Basically all you have to do for that if you want to is run 14-16 ga. cable from your power hook-up on your amp(s), to a switch, then from the other terminal on the switch to your remote hook-up on your amp(s). This is most helpful if you are running multiple amps, especially for regular speakers and 1 for sub. and you want to turn your amp off for your sub and/or turn off the other amp(s).

[shifty]

Originally Posted by GoobersBlueBurban

I know most people like the convenience of having the amp come on with the cd player, but I like to have my amp(s) on a switch. Basically all you have to do for that if you want to is run 14-16 ga. cable from your power hook-up on your amp(s), to a switch, then from the other terminal on the switch to your remote hook-up on your amp(s). This is most helpful if you are running multiple amps, especially for regular speakers and 1 for sub. and you want to turn your amp off for your sub and/or turn off the other amp(s).

Not trying to shoot your post out of the water, but that's a really inefficient way to run it, there's a cleaner/better solution. The proper way to do this is to use a relay, the same way you would do the relay -headlight fix on our older trucks.

Here's a quick explanation of how to use the relay in a system like your to prevent waste:

Go buy a relay ($5?)
Pick up a toggle switch.
Connect ACC power from the fusebox to one side of the toggle switch using a 18-20 gauge wire.
Connect the other side of the toggle switch to pole pole 85 on the relay.
Apply ground to pole 86 on the relay.
Put positive voltage from the battery to pole 87.
Attach the amplifier turn-on lead to pole 30.

With this setup, you are basically running the amplifier power directly to the amp (passing through the relay) and instead of running a heavy power wire from the battery to a toggle switch (which is unsafe), you'll be using the 18-20 gauge wire to "open" and "close" the relay, allowing power to remotely be added or removed.

This setup will also kill any amplifier "turn-on thump" you would typically have using a straight toggle switch, which will lengthen the life of your speakers, especially your subwoofers. It only costs $5 to setup. It also reduces the length of the power wire run, which will decrease the likelihood of loss....and you won't choke out the power by forcing your amp line to run through the switch.

I would run one dedicated relay per amplifier power wire.



An explanation of how to do it in the trucks is here:
http://67-72chevytrucks.com/vboard/s...d.php?t=173230

An example of how to do it with a dual electric fan setup in our trucks is here:
http://67-72chevytrucks.com/vboard/s...d.php?t=180436

[shifty]

PS - I think my numbers are correct above.

Here's a great wiring diagram tool that shows you a full stereo setup:

http://www.bcae1.com/images/swfs/rel...eassistant.swf

Here's more info on how to use the switch in a relay:

http://www.bcae1.com/swrelay.htm

[pat]

Could a decent 4 channel amp run a 5 1/4 component spkr system and two 8" subs? I have a Kenwood P-605ie component system and still need subs. Sorry not trying to jack the thread.

[djracer]

Pat yes it could! You just need to be carefull that the load on the third channel of the amp doesn't get too low. You would need 8 ohm subs if you use 2 subs and 4 ohm if you run a single sub!(if you run dual voice coil subs this would change!) Most 4 channel amps will only run 2ohms stereo or 4 ohms mono!

Kevin

[shifty]

I would get a name-brand 1-ohm stable 4 channel amp. Then get two 6 ohm JL Audio subs or a single dual voicecoil sub and wire them in parallel.

[djracer]

Most 4 channel amps are going to be 2 ohm stable only! A 1 ohm stabe 4 channel is rare and very expensive! I own a mobile car stereo shop if anybody needs anything send me a Pm.

[shifty]

Really? You must not carry Audiobahn products at your shop. Check this baby out, it's 4x75w at 4ohm and 1x1200w at 1ohm!!! Price tag is less than $600 several places on the web (it's $580 here, but I saw it for $450 elsewhere):

http://www.cardomain.com/item/ABNA4075HCT

Cool case too, perfect for our trucks w/the flames and all:



Specs:
300W High Current Series 4-Channel by Audiobahn:

• 75W x 4 @ 4 Ohm
• 150W x 2 @ 4 Ohm
• 300W x 2 @ 2 Ohm
• 600W x 2 @ 1 Ohm
• 1200w x 1 @ 1 Ohm

Last time I checked, Rockford has the T8004 for around $450 (1ohm stable in 4ch mode, 2 ohm stable with two bridged channels)...US Amps and Hifonics both sell a reasonably priced 4ch amp that's 1ohm stable. Most of your high current 4 channel amps will handle it and most that I've seen are under $500 for such a setup. Really not that poorly priced.

[panhandler62]

Also.....

If you run standard 3 way speakers on "high pass" you will significantly decrease the amp load so be sure to run a couple in series or inline a 1 ohm resistor to keep the amp from overheating.