4 RCA pre-outs to 2 channel amp
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=24185
Printed Date: May 15, 2025 at 9:36 PM
Topic: 4 RCA pre-outs to 2 channel amp
Posted By: Druid_goldeyes
Subject: 4 RCA pre-outs to 2 channel amp
Date Posted: January 08, 2004 at 1:39 PM
I'm tryind to install my new Rockford Punch 2 channel amp to my Kenwood deck. the deck has 4 RCA pre-out wires, 2 red, 2 white. the amp only has 2 RCA plugs: one labeled left, one right. What goes where? I plan on running it bridged for my sub. Also, I've heard that stuffing the sub box with polyfill "tricks" the sub into thinking it's in a bigger box, making it louder. However, does this also decreace the responce/sound quality? Cheerz
Replies:
Posted By: meh66
Date Posted: January 08, 2004 at 2:20 PM
Hi, The 4 RCA pre-out wires simply mean the Kenwood Deck is capable of controing two amps. I am curious, does this deck have sub woofer eq controls? I am not sure about the polyfill question. ------------- MEH66
"Car Performance and Mobile Electronic Enthusiats"
Posted By: Druid_goldeyes
Date Posted: January 08, 2004 at 2:26 PM
i'm not sure about the sub eq control. I'll have to check when i get home. So what you're saying is i only have to conect one red and one white? Or both red?
Posted By: mrcarsound
Date Posted: January 08, 2004 at 2:52 PM
Filling the box is mostly used in order to compensate for a too small box. It might come in very handy If you are restricted in available space and still want to respect the desired / recommended enclosure size. Besides giving the impression to the subwoofer that it is playing in a bigger box it has some other advantages : - decrease / elimination of so called 'standing waves' will result in smoother / flattened frequency response - slightly better efficiency (don't expect any miracles !) When filling the box make sure the area directly behind the woofer cone stays free of filling material as - the cone might come in contact with the filling - the woofer might 'choke' Do realize that you will have to experiment and measure a lot with the quantity of filling material before you will obtain the best result. Good luck ! Eric
Posted By: Sweekster
Date Posted: January 08, 2004 at 4:53 PM
What you'll probably need for the amp is a y connector (splitter) for the RCAs. But instead of splitting the RCA signal you'll do just do it in reverse. So you run the RCAs (right and left for both) from the radio to the y adapter. That will turn 4 signal in to 2. And then plug the Y adapter into your amp. Here's an example of what one looks like
https://www.scosche.com/efx/products/audiocable/AFMMYP.asp
Hope that helps ------------- Duane...
If you think you're confused, imagine how you feel. 
Posted By: DYohn
Date Posted: January 08, 2004 at 6:22 PM
Just use one set - one red and one white from either the front or the rear output - to your 2-channel amp. I usually use the rear set in a head unit without a sub output.
Posted By: Deez_Nutz
Date Posted: January 08, 2004 at 11:18 PM
may i ask why you would hook up all 4 rca's from the deck usually they are like that for a front rear or even a non fader hookup not to be put together whats the point please let me know (not trying to be rude trying to learn)
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My Ride
https://members.cardomain.com/kwickymart
Posted By: fatdaddyjoe
Date Posted: January 08, 2004 at 11:25 PM
what is the model of your radio?? that will help us in telling you what set you should hook up........there is no way you will use all 4 (both sets ) on a 2 channel amp..............WHATS THE MODEL NUMBER????
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THE LOUDER THE BETTER !!!!!!
CAN YOU FEEL IT ?????
Posted By: Deez_Nutz
Date Posted: January 08, 2004 at 11:36 PM
if there is a set for non-fader use them they are the best for subs no matter how much you fade it front bac side to side same amount of bass i got my eclipse hooked up that way sounds great
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My Ride
https://members.cardomain.com/kwickymart
Posted By: Druid_goldeyes
Date Posted: January 09, 2004 at 12:10 AM
Thanks for all the help guys. They are for front and rear (I actually cracked open the manual :P). The non-fading is only on the model above mine. Thanks again for all the help. Now I just have to do all the in-car wiring. I do have one other question, but I'll put that in a new post. It should be close to this one. Cheerz, goldeyes
Posted By: geepherder
Date Posted: January 09, 2004 at 3:16 PM
Goldeyes, Typically, decks with 2 sets of preouts are front/rear like you said your's is. Most of the time people use the rears for the subs, but the fronts will work just as well. If you're not planning on adding a 4 channel amp or upgrading your deck in the near future, simply use some y-adapters as Sweekster recommended to combine the front/rears. In theory, this would create a non-fading output to your sub amp, so when you fade front to rear for your main speakers, you don't get the annoying fade from the sub as well. Let us know if this works, or what you do, I'd like to know.
Posted By: sssssss27
Date Posted: January 09, 2004 at 4:33 PM
Sweekster wrote:
What you'll probably need for the amp is a y connector (splitter) for the RCAs. But instead of splitting the RCA signal you'll do just do it in reverse. So you run the RCAs (right and left for both) from the radio to the y adapter. That will turn 4 signal in to 2. And then plug the Y adapter into your amp. Here's an example of what one looks like
https://www.scosche.com/efx/products/audiocable/AFMMYP.asp
Hope that helps
Don't do that, all it will accomplish is generating a signal that is unusable not combining them. Like everyone else has said, just run one set.
Posted By: Deez_Nutz
Date Posted: January 09, 2004 at 11:27 PM
i know one set will do just fine put it on the rear set and let it go no prob just keep the bass level at a good setting and be done with it WOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ------------- My Ride
https://members.cardomain.com/kwickymart
Posted By: Druid_goldeyes
Date Posted: January 10, 2004 at 1:55 PM
One more question for you guys, will there be any problems with electronic interference if I mount the amp on the back of the sub box? I'm driving a golf, and space is kinda at a premium, so i need to save every little bit that i can. Cheerz ------------- Not even the sun can banish the phantoms of our land. Nevertheless, we cower in the darkness and pray for dawn.
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