Robert373

Since there seem to be a ton of people on here that know more about stereos than me, I've got a question. There will be more to come also I'm sure.

My 16 year old wants to use an amp to power his rear speakers (he just bought new ones). Problem is he already has a sub in his trunk (and nothing else due to the size) and after consulting the installation guide on the deck, there is only 1 set of RCA outputs that can be rear speakers or sub. How do you wire it so he can use the amp for a sub, and a separate amp for the rear speakers? Only way I can see is split the RCAs to each amp, but then don't the rear speakers have too much bass?

Once we get this sorted out, I'll need help with all the settings on the amps, but one problem at a time.

03 ant a hemi

Your amp should have imputs for RCA cables and also speaker wire direct. The sound is not as perfect usingthe speaker imputs but it works well.
You hook up the speaker wire comming from the stereo to the amps imput, then hook it up like normal.

Hope that helps

Robert373

The amp that he got with the sub (MTX) has speaker inputs, and I tried last night to wire it that way with that amp running the back speakers. For some reason the speakers would not work. (Maybe the way the amp was set?). Also he bought the sub box/amp used and the speaker inputs on that amp require a specific plug to input them, and of course when he bought it, it never came with that plug. I did my best to modify crimp on type connecters to fit the pins, but they were not perfect (and a real PITA since they recess them into the amp, and they are close together).

The other amp is an old Alpine 3554 I myself bought about 20 or more years ago, and never used myself (but a friend got a few years free use out of it). That amp has no speaker inputs, only RCAs. I remember at the time I wanted to use it with speaker inputs, the guy sold me adapters that converted the speaker inputs to line level inputs (RCAs). After all that, I still could not get it to work with my factory GM deck, so that is why it never got used.

Any idea why the MTX amp would not work with the speaker inputs? I just hooked the rear speakers back to the speaker inputs for now to get it working.

Or should I try to find adapters again (no idea what happened to the ones I bought) and use the MTX amp for the sub. and use the converted speaker inputs for the Alpine.

JJK98CTD

Hello, You could get a .5 din old school eq with crossover then run RCA cords to each amp or a crossover and mount in the rear of vehicle then wire to amps. or they used to make a single rca to a fader control to double out the rear then you could turn the **** for the what you wanted. Or a high to low level converter.

Good luck,

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B-North

Do either of the amps not have rca outputs. Some do so you just run short rca's from one amp to the other.

Robert373

No. The MTX has 2 speaker outputs, and th Alpine has 4 speaker outputs.

Robert373

Option #3 looks like the ones I bought years ago. I think that is the ticket.

The other 2 options you present are out of his price range. Took him months to save up for his new speakers.

dvst8r

Just split the RCA's using RCA Y cables, and set the High and Low pass filters each of the amps respectively. That way the Sub will only get signal below X hz, and the rear speakers will only get signal above X hz.

Mike Holmen

I did that on my stereo in my truck, works well and a cheaper option. Your deck, does it have sub-outputs RCA's? That works the best, you might need a device so you can tune out hi freq for the sub. Most newer deck have at least 5 RCA's outputs (two for the front, two for the rear, and one for the sub).

Those mixing boards work great but are more complex. I have Apline one that it tunes itself for the truck. Hated it, went back to the rca spliters. I run four amps in my truck on 12 speakers.

Robert373

This does sound like the easiest option.

I was going to ask what the "LP" and "HP" switches on the alpine amp were, now I know (low and high pass).

So if you wanted the amp doing just the rear speakers, set the amp to HP, and for the sub it would be LP?

Also what does "gain" do?

Robert373

The deck only has 1 set of RCAs for rear/sub, and you need to somehow select which one. If it had 1 set only for the sub it would be golden. I suspect it is a lower end Sony deck, but as I said, on a 16 year old budget, its better than the factory GM deck.

My contribution was giving him my old Alpine amp, other than that it's on his dime.

dvst8r

You got it.

Gain on the amp adjusts the input level. Well it doesn't adjust it so much as limit it. It is sort of like a separate volume for that amp. It allows you to match the output between amps and the rest of the system, as well as it allows you to limit the overall output of that amp to keep the amp from clipping or the speakers from over extending.

dvst8r

Also depending on the rear speakers being used and the amount of power you are pushing them with, you may want to just run them full range.

Robert373

Awesome, thanks. I picked up a couple Y connectors last night and we'll get this done this weekend.