Which is the hotwire on the rear speakers on a C4 Corvette?
 

This is on an 84 Corvette. It does have the Bose system which is making it problematic. Okay now here's the situation:

My buddy and I were to install the amp and the subwoofer in the car yesterday, we only got the amp up and running. We ran the power line for the amp to the battery through the doors [i'll be running them through the firewall, i'm just running things as quick as possible to make sure i'm getting power]. Now since I couldn't find much metal on the car that was close to the back of the car, I used the seat tracks rear bolt on the passenger side seat to ground the amp. Finally we ran the remote wire exposed to the fusebox and connected it to the cluster's fuse.

The amp started up fine when the ignition was turned on, and turned off fine when the ignition was turned off. Great! :D

Now the problem is the following. We ran the speaker wire from the amp to the rear speakers instead of running an RCA cable to the headunit Then ran speaker wire from the amp to the subwoofer. We turned the ignition on, and got the radio, and the four speakers, and the amp turned on, but no sound from the subwoofer. Now the thing that is making it problematic is the four wires located on each speaker in the rear because of the Bose system. Which is the hotwire? Doesn't anyone have a diagram or advice on how to run the subwoofer off the rear spakers instead of running RCA cable? I can run the RCA cable, and I do have it, but we've ran speaker wire off of other cars from the rear speakers into the amp and had them provide the amp the connection to the subwoofer.

Anyone with previous experience with a similar setup want to lay some advice on me?

Thanks! https://www.corvetteforum.net/c4/vetter/thumbsup.gif
-Steve

Re: Which is the hotwire on the rear speakers on a C4 Corvette? (puck)
 

I'm not quite sure what you're doing based on the information provided: Use the factory signal wires spliced into the new Head Unit? What type of Head Unit did you buy? Is there a separate preamp output for the sub or is there a crossover incorporated in the amp? If there is a preamp for the sub at the Head Unit, you may have to use it to get the correct frequency to the sub. Are you looking for a power source to a self powered sub? If you want to use the Bose wiring, it's the pink wire at the rear speakers (Black is ground and the signal wires - depending on side - should be dark blue, light blue, yellow and brown); however, power is controlled by the Amp Relay and you're going to have to find some way of powering up the Relay when you turn on the Head Unit. Are you trying to use the Bose amp to power the sub? I doubt there's enough power to do so. Please provide more information as to how you're getting the signal to the amp and the speakers and maybe I or someone else can help you further. As a side note, make sure you ground the Head Unit and the Amp at the same place. Otherwise you run the risk of alternator whine.

Re: Which is the hotwire on the rear speakers on a C4 Corvette? (SunCr)
 

Another thought that just occurred to me is that if you're trying to use the Bose connectors at the speakers, it isn't going to work. The audio signal wires are preamp outputs which is a very low a/c voltage (from the Bose Head Unit) and there's nothing positive or negative about them. They of course are electronically connected to the individual amps which then amplify the sound and drive the speakers. You need to go directly to the speakers; ie, bypass the Bose circuitry.

Re: Which is the hotwire on the rear speakers on a C4 Corvette? (puck)
 

I'm not using the amps from the Bose speakers to power the subwoofer. I have a seperate 800W Profile Amp that will power the subwoofer alone.

How am I to get sound to the subwoofer now? I used speaker wire to connect the subwoofer to the amp, that's fine; however, I do need to run wires in order for the sub to get sound. How do I do this? I know I can run an RCA cable from the amp to the headunit, but isn't there some way to run speaker wire into the amp which would then provide the connection that would tell the subwoofer when to come on? Or would I have to just run the RCA cable? It is an aftermarket headunit by the way. I know that it's possible to run the wire from the rear speakers, to the amp and then run more speaker wire to the sub, so in turn the amp would power the subwoofer, and still get the connection from the other speakers on when to come on. I'm new at audio equipment, but I do know a little.

Thanks for responding, if you need more information i'll be happy to answer. I'm at work so I may not respond for another hour or so.

Steve

Re: Which is the hotwire on the rear speakers on a C4 Corvette? (puck)
 

I take you're running two amps then? You're approach, and not that it's wrong, is little different from how I would look at it. What you want to do is provide power to the amp (which you've done) and audio inputs from the head unit. Then from the amp, the amplified outputs to speakers and sub. If there is a dedicated pre amp output from the Head Unit for the sub, then I'd use this for your audio input to the amp - it's going to be much cleaner. If not, you need to get an audio signal (pre amp) to that Profile Amp and then the amplified signal to the sub. The key is that it has to be a pre amp signal. You can't use the signal that's all ready been amplified at the speaker. Try this(assuming you using two amps): 1. remove power from the speaker amp. 2. take an audio signal from this to your sub amp and with the sub hooked up to the amp, turn on the radio. The sub should work. If you don't have a pre amp output for the sub, then look into adding a Crossover. It will separate the low pass audio signals from the head unit so that they are directed to the amp powering your sub.

Re: Which is the hotwire on the rear speakers on a C4 Corvette? (SunCr)
 

Another thought, Are you using the amplifier in the Head Unit to drive the speakers and adding the amp to drive the sub? If so, make sure the amp accepts speaker level inputs and that you're going into it when wiring the amp. If so, input from any speaker should provide the sound you need to get sound out of the sub.