i have 2 12s that i want to install in my truck and im going to use the stock radio till i can get a new one but where do subs hook up to on the stock system?

 

The factory radio does not have subwoofer outputs nor does it have enough power to drive any sub by itself, much less a pair of 12's. You need an external amplifier with a built in crossover for the subs to work properly and sound good.

Check around at Best Buy or some good independent car audio shops. There are some good deals out there. But don't connect the radio to the subs, it won't work well at all and you could damage the radio, the subs or both.

Jimmy

 

I will ASSUME you have an amp. Otherwise, the rest of what I am going to write doesn't matter as there is no way your stock stereo can ever satisfactorily power a set of 12" subwoofers. Subs without an amp are like a good running truck with no gas - useless.

Next, I am assuming your amp has a built in cross-over. This works to make sure that the amp is only reproducing the sound frequency that you desire the speakers to reproduce. Cross-overs are also called "low pass filters" or "high pass filters." A low pass filter allows frequencies below a certain range to get through to be amplified, while blocking all frequencies above the filter point. Low pass filters are often selectable, given you an option of filtering frequencies above 60 Hz, 80 Hz, and 120 Hz, for example. If your amp has a high pass filter, it is designed to power speakers that are not subs and will not work well.

First, you will have to use the "high-level" or "line level" inputs on the amp because there are no RCA pre-outs on the stock stereo. This will entail splicing into either the front or back speaker wires and running four individual wires to the amp. It is not incredibly difficult to do, but you will have to mess with the "gain control" on the amp to get optimum sound quality. It is a stupid little plastic screw looking thing that takes a little slotted screwdriver to turn. In my experience, the RCA cables produce a much better sound quality, even after meticulously adjusting the gain on the amp, but you won't be able to go that route. This is also where your low pass filter comes into play. Since the factory stereo is sending a wide range of sound frequencies over the speaker wires, you need to get rid of the high frequencies. You aren't using the sub to blast out cymbals, after all. Most after-market stereos with a dedicated subwoofer output will have a built in cross-over that sends only the desired frequencies to the subs.

Second, you need to locate the switched power wire on the back of the stereo. It is also called the remote power on wire. Often, this wire is blue with a white stripe, but not always, so you will need to check. It is the wire that powers up a power antenna when you turn on the radio. This powers the amp on when the radio is turned on and allows it to power off when the radio is off. Use your voltage tester and find the wire that has power when the radio is on but has no power when the radio is off.

Third, if you have 2 12's, I am ASSUMING you have a pretty hefty amp. I don't know what subs you have, but I am guessing you will want at least 250 watts of "RMS" power to push those subs, possibly considerably more. That means you will have an amp with upwards of 500 watts total power. You will need to get some high quality 4 gauge wire for a power lead and ground. Welding power wire has worked nicely for me in the past, and it is pretty cheap as 4 gauge goes.

Fourth, put an appropriately rated in-line fuse (the amp rating of the fuse depends on the maximum power of your amp) as near to the battery as practically possible. Inches away, not feet. This way, should your power wire short out, you eliminate the risk of having all of the electrical crap under the hood burning up. I would solder any connections made with the 4 gauge (like the connection between the wires and the ring to attach it to the battery, the connections to the fuse, and the connection to the ring for the ground) with the exception of the connection to the amp itself, of course.

Finally, if your amp is large enough to appropriately power 2 12's, I would consider getting a capacitor. They are not too expensive, and they do make a considerable difference. It will eliminate a bouncing voltage gauge and dimming headlights when the bass hits. Make sure you get one that is big enough for the amp, but there is no reason to go overkill on it. A 1 farad capacitor is probably sufficient up to 1000 watts total power. If you get one of these, charge it exactly as the instructions say. There can be 1000's of volts of electricity stored in a capacitor, and it can and will jack you up.

 

lmao, the stock radio is like 20 watts max output.... fail
and theres not any way to hook an amp into the radio (if you even thought of that).... double fail.

 

too bad you don't have a stratus, some of them come with an amp under the passenger seat. wish they did it in the dakotas.

 

This is simply not true. The method I described above will allow an after-market amp to be installed using the stock head unit, if the amp has high level inputs on it.

Once upon a time, back when dinosaurs roamed the Earth (or when I was in high school) there was no such thing as a head unit for a car with RCA pre-outs (or at least not one that I could afford making minimum wage). I had an Escort with a Pioneer TAPE DECK (yeah, I am that old) that I hooked an amp up to. I had four speakers (two little dinky crappy things in the dash, and two nearly as crappy 6x9s in the hatch). I bought a full-range MTX box and a Precision Power amp from a pawn shop. I used the front speaker leads as the inputs for the high-pass part of the amp (to power the tweeters on the box) and the rear speaker leads for the low-pass part of the amp (to power the subs). For a rusted out, carbed Escort that didn't like to run when it was below 40 degrees outside, it sounded pretty decent.

 

UGH - those factory amplified systems are a pain when something breaks.

My wife had a Jeep Grand Cherokee with the Infinity system. It constantly blew the dash speakers. And, those crappy little speakers were 2 ohms. Try finding an after-market, 2 ohm, 3.5 inch speaker. They do not exist. So, to get the radio working properly required a trip to the Chrysler dealer to purchase the factory Infinity speakers. $80 a piece. And garbage. But, the only way to get around it would have been to install a new head unit and completely re-wire the Jeep for 4 ohm sound.

I have a Mustang with the Mach 460 sound system as well. It sounds decent with an aftermarket head unit (you can, in fact, hook one of these up to the factory amps in that car with the proper wiring harness), but I am locked into using the original equipment speakers.

After-market speakers will effectively cut the power of a two ohm system in half. Imagine making your stock stereo half as loud as it was. Not desirable, IMHO.

 

Really I think it would be to much of a pain to try and figure out. I mean like wait a little bit and get a new head unit mine was only 130.00 at crutchfield and when I had my subs it was power wire,remote power wire and rca's took me a matter of 20 min to get installed and hidden

 

 

Whether he has the factory amp or not (some Dakota's had it and some did not, depends on the model) he can add an amp without too much trouble by using a line level convertor. Back when I was an installer we also called it a step-down convertor because it reduces or steps down the high level speaker outputs from the factory radio to a low level RCA output. The better quality convertors will also have gain controls to match the impedance of the output from the radio to the impedance of the RCA outputs to get the best sound quality from the new amp and speakers.

The OP could use a convertor and a good set of quality shielded RCA cables and a good amplifier with a built in low pass crossover for the subs and get really good bass output from it. Trouble is, when he adds the bass to the system it may overpower the factory full range speakers so he won't be able to hear the midrange and high frequencies. If he were to use a good 4 channel amp, he could connect the front outputs to the door and rear side panel full range speakers, and use the rear channels for the subs. The downside to that is you lose the fader control, unless you use a separate 2 channel amp for the subs and a separate 4 channel amp for the mids and highs. Adding new 4 ohm full range speakers won't decrease the power of the factory system. If anything, going from an 8 ohm speaker to a 4 ohm would be louder due to the decreased impedance (resistance) presented to the radio.

A few manufacturers back in the day offered 6 channel amps that did the whole system, ADS and Xtant are a couple I remember. I think JL makes one nowadays. I remember they were pretty expensive. The other downside to adding bass to a factory system is he will likely need to upgrade his factory full range speakers if he adds an amp to them, which will also cost more for the new speakers and installation too if he doesn't do the work himself. And you don't really need huge gauge power wire, a typical 8 gauge power wire kit from Walmart or any other store will do fine for most amps you can buy, especially for a simple 2 channel amp driving a pair of subs. He will need to be sure the new amp is stable enough to handle the impedance of the speakers if it is bridged, or run in a monaural single output which can increase the power to the subs and therefore make the bass louder. One safe configuration would be to use a 2 ohm stable amp and a pair of 8 ohm subs wired in parallel and the connected to the amp in mono. In a bridged configuration the amp will always see half the ohm load presented to it.

Jimmy