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Sub woofer amp wiring

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Old 09-13-2011, 10:08 AM
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Default Sub woofer amp wiring

So the old subs on my 1997 were old and breaking apart. I bought a more powerful amplifier which I will place in the pouch of the rear door and have ordered new speakers that will match the power & impedance specs of the amp.

There are six wires that enter the old amplifier circled in blue on the right side of the following diagram.....

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I need some help reading this diagram correctly and would appreciate you taking a look at it to help understand function of the six input wires to the sub amp.

1,2,3 - These look like audio connections to me. What I'm not sure of is whether the audio to the sub amp is mono or stereo. One possibility is that #1 is a noise ground and 2/3 are the +/- audio (mono). Another is that 2 & 3 are the positive audio channels and #1 is a audio 'common' (or negative) indicating stereo inputs.

4) Clearly the power supply

5) not sure, could be a remote on/off for the sub amp

6) clearly a ground

So, in the absence of RoverChris, and nagarover, anybody else have any car audio expertise for me? Please? Thanks in advance.

I'm also going to post on dweb. No disrespect intended. Just trying to reach another group of potential resources.
 

Last edited by WaltNYC; 09-13-2011 at 12:20 PM.
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Old 09-13-2011, 11:24 AM
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One looks like a ground and 5 a remote on. I would check the power and switched power with a meter, and ohm out the grounds, then the only thing left are the 2 audio wires
 
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Old 09-13-2011, 11:57 AM
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Originally Posted by tweakrover View Post
...., and ohm out the grounds......
Not sure I understand what you are suggesting. Could you please clarify? Apologies if it is a dumb question. I have a multi-meter and can check for power easily enough, it is just this specific phrase that I don't understand.
 
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Old 09-13-2011, 02:49 PM
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Take the two audio inputs you're not sure about and use a door speaker to test if they're left and right by manipulating the balance on the head unit. If you get an audio signal from the door speaker on each and how the balance **** affects them will give you your answer.

I would also consider that the stock amp almost certainly includes a crossover or filter somewhere. The amp won't be processing the high frequencies. It also makes sense for the mids and tweeters to be working on a crossover or low-cut filter, but I don't know the location of the processing since I'm not that familiar with this install.
 
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Old 09-13-2011, 04:13 PM
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By ohming out I mean checking continuity between it and the ground. An ohm is the measure of electrical resistance.
 
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Old 09-13-2011, 10:38 PM
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sorry for the big explanation, I'm not very good with explaining these things for everyday people so please try to bear with me. OK so pin 4 is power supply but bear in mind that an aftermarket amp will probably draw more current than the stock amp, but lets take a quick look your MTX amp is 125 watts into a 4 ohm load and the 2 subs you purchased are 8 ohms each, so if you wire them in parallel your amp will see a 4 ohm load, now ohms law tells us that power/volts=amps or in your case 125/12=10.4 amps, now keep in mind this is RMS rating so peak power you will be exceeding the max current draw of 10amps on the stock fuse, I wouldn't worry about it unless you blow the fuse, in which case I would strongly consider running a new power wire (of course if you wanted to try a 15 amp fuse you probably wont cause a fire). ok pin 5 is amp turn on wire as tweak said, I'm about 99% sure on that one as I remember the colors but metering the wires is still a good idea. 6 is a ground, when you "OHM" out the ground just put your meter on Ohms and look for a 0 that means pure ground with no resistance 1 or 2 is ok 5 or more you may want to reinforce it or just tap a new ground. just a side note the reason you lose ground is because the ground starts at the battery and then it goes through painted surfaces, welds, rust or anything else that may weaken the signal, and the problem with it is if your source unit (radio) and output unit (amp) see a different level of ground potential then you will introduce noise into the system such as alternator whine, hissing, or popping. Now for the fun part pins 1, 2, and 3, I am not 100% sure on this because I personally would never integrate a factory preamp signal with an aftermarket amp, but if you choose to for financial or other reasons I will try to help the best I can. pin 1 is a shield (this is literally just a ground), pin 2 is a positive mono signal and pin 3 is the negative mono signal. In order to connect these wires to an aftermarket amp you will need an rca jack to attach to it and you will use pins 2 and 3. now why wouldn't I use those and what would I do instead? when you mess with (rewire) shielded cables you can introduce noise, not to mention these are very skinny signal wires and they are difficult to work with, but I have seen this done successfully many times. It's just my personal opinion that its more hassle than what its worth between the initial effort and the common issues that arise later on if the connections come loose. I would get a cheap line out converter (just do a Google shopping search for it you can probably get one for about $10) then just tap that into the passenger side rear speaker wires and your good to go.

I hope this helps, if you have any more questions email me as I probably wont be back on here for a while since I drive a Dodge Dakota now!
 
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Old 09-26-2011, 11:35 AM
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For all those interested....

This went very smoothly and the six wires into the connector on the stock sub-woofer as as follows...

1) Grounding shield for the audio connection. I connected this to the ground connection on the amp along with #6.

2) Positive audio (mono)

3) Negative (ground) audio (mono)

4) Power - only receives power when ignition is in position 1 or 2.

5) Remote on. Only receives power when radio head unit powered up.

6) Ground.

Eventually I may need to relocate the amp which powers the subs off the door and into the cubby space on the passenger's side, but for now I'm quite pleased with the results. No ignition noise can be heard and I have a little more 'ooomph' when rockin down the road.

Thanks for all the help.
 
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