How to power all 4 speakers and subwoofer

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=38667
Printed Date: May 10, 2025 at 2:17 AM

Topic: How to power all 4 speakers and subwoofer

Posted By: edd1
Subject: How to power all 4 speakers and subwoofer
Date Posted: September 06, 2004 at 8:45 AM

Hi guys

I recently purchased a head unit for my car and I would like add more power with an external amp and a subwoofer. I have the following problems -

(1) The HU doesn't have a wire for an external amp, but it does have a wire for the power antenna. However my car doesn't have a power antenna, so how would I connect the remote trigger wire from the external amp to the HU ?

(2) The HU has only 2 RCA line outs (presumably for left and right). However, I would like to power all 4 speakers as well as hook up a subwoofer in the trunk ? How would I go about doing this?

(3) Would I need to purchase a 4-channel amp or a 2-channel amp in order to do all this ? I believe my set-up is pretty much a tri-mode setup with one amp powering 4 speakers and a subwoofer, but the problem is the existence of only 2 pre-amp outputs, not 4 !

P.S. Thanks a million. I have no idea on this !

Replies:

Posted By: switch_hitter
Date Posted: September 06, 2004 at 9:06 AM

the easy fix for only having 1 set of out puts, is to add a 2-way electronic cross over......that will give you a low output, and a mid/high out put out of the cross over. And it will help your sound a bit too.

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2 Memphis HPO 12s
1 Memphis 1000D
2 Memphis 8s
1 Memphis MC200
4 Memphis 3way 6 1/2s
1 Memphis MC3004
4 Memphis Tweeters
1 Memphis 3-way electronic crossover
2 Memphis 5 1/4
2 Memphis 4s

Posted By: stevdart
Date Posted: September 06, 2004 at 9:24 AM

1. Connect the amp remote wire to this wire on the deck. If for some reason the amp only powers on when the radio is selected, then move the rem wire to a switched 12 volt source instead of the head unit.

2. Yes, the preouts are left and right. Choose an amplifier that has a set of full-range output RCA's, which will connect one amp with another amp and provide a full signal.

3. Use a 4 channel amp for the interior front and rear speakers. You won't have fade control on the deck, but you can adjust the amp rear gain down to lower the volume of the rears. You should avoid tri-mode unless you are willing to learn a lot about it first. Instead, get a second amp to power the sub. There are also 5-channel amps you can choose from.

And don't you have a manual with that deck?

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Posted By: edd1
Date Posted: September 06, 2004 at 10:55 AM

Thanks a million. Your comments have cleared up a helluva lot here !

What I am gonna do is buy a 4-channel amp and power the front speakers only using 2 channels and bridge the 2 rear channels on the amp to power the sub (i.e. combine them in mono mode). I believe this is the basic 3-channel setup.

However, my question is, the HU only has 2 pre-amp outputs for "left" and "right". But I want the 4-channel amp to only power the front left speaker and the front right speaker. How do I connect the RCA cables to the input terminals on the amp ?

In other words, do I simply use RCA cables to connect the 2 pre-amp outputs on the HU to the front left and front right input channels on the amp ???

Posted By: customsuburb
Date Posted: September 06, 2004 at 12:31 PM

If your amp has a switch labled 2ch. on one side and 4 ch. on the other then run your single rca cable to the front inputs (if you dont get any sound connect them to the rear instead). Then switch the switch to the 2 ch. Here is a picture: amplifier_side.jpg

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Posted By: stevdart
Date Posted: September 07, 2004 at 9:56 PM

If the amp doesn't have the switch shown above, you would buy two Y-splitters (1F-2M). Connect the RCA's from the head to the splitters, then run one into both front and rear left, and the other into both rights.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.