I just installed some subs and can only get one to work. I have a 4channel amp with 2 sets of RCA jacks. Each set has a white and a red input. I think channels 1 and 3 are white and 2 and 4 are red.

I have 2 12's bridged and I know for a fact that the channels work. The problem is with the RCA inputs.

I have a RCA cable that has a red, white, black, and blue input. I hooked the white and red into the back of my Alpine deck into the subwoofer inputs. The blue and black are just sitting back there.

Now, on the amp end, I hooked the the red and white RCA inputs into my amp and only one sub works, again the black and blue input are just sitting there. If I switch the inputs to the other two open inputs (channels) the other sub works.

My question is do I need a specaial RCA cable that has 2 inputs on one end and 2 (sets a total of 4) on the other end?

 

Take pics of the amp with the wires running into them.

 

Also, does your headunit have inputs for front and rear speakers? Does it have RCA hook ups for those?

 

I think I have figured it out. All I need is Y adapters. Its a piece that makes one RCA input turn into two.

 

Bad idea, its designed to split a signal not add signals. It may fry your head unit.

Run one input to the amp.

This a/v stuff is touchy and do to the wide variety of products its hard to point you in the right direction. List your HU and amps make/model. If i can read the manuals for them we can help you more.


On my xtr400 it likes one input, with two the sub seems to get less power. Although this amp was a refurb back in 99 and has since suffered a rca jack failure. It was repaired again.

 

My stereo is a Alpine 9883

Here is a pic of my amp. Since the cord from my head unit only had one set of red/white, I went and bought splitters. I know have two sets of white red/white.

I also attached a pic of the splitters I used.

 

I think you just need to hook it up different. Your headunit should have 3 sets of RCAs coming out of it, 1 subwoofer one and 2 for the speakers. Since you've got a 4 channel amp and not a Mono subwoofer amp you need inputs in both pairs of the RCA's on your amp. Basically what you need to do is pull out your headunit and unhook the single pair of RCA inputs from the subwoofer output and connect both pairs to the speaker outputs. Then connect both pairs to the amp. It'll be more important to adjust LPF correct on the amp now since youre going to be sending it more than just low frequency but it should work fine and sound good. Using the Y splitters would work too but I would think it wouldnt be as loud since you're splitting the signal and lowering the input volts to each channel. You'll probably have to turn up your gain a little to make up for it which means more chance of clipping.


I think you're confused. He would be splitting the signal by doing that and I couldnt see him frying the headunit. He would be taking 1 pair of outputs coming out of the headunit and splitting them.

 

I tried the speaker outputs and it didnt work. I got sound but sounded like ****.

I think i have it figured out.

Looking at a picture of my amp, how should I set my settings?

 

Here is a little paint picture of what I am doing.

 

It sounded like **** because you probably didn't have the settings on the amp set right. Do it again how I said to do it and then put both of the little switches to LPF and then (Its kind of hard to tell but I think this is what you should have to do) put the dial on the right that has LPF under it to probably inbetween the 2nd and 3rd dots from the right (about 80hz). You can mess with it a little from there but that should get you started good.

Splitting the signal with the Y splitters will physically work but I think it wont be good in the long run, nor will it sound good. Your headunit puts out probably like 2-3 volts through the preouts in the back, which isn't that much. You using the Y splitters will probably cut that in half, which would mean you are going to have to turn up your gains. Higher gains induce more clipping which is pretty much your enemy lol. It'll kill your subs.

 

I played with the LPF and if I had it on that setting it sounded even worse, lol...?

I had every setting on the amp at half way just to see if it worked.

 

After reading his first post and seeing the Y adapters. I was thinking he wanted to add the front and read rca to the amp. Which would be bad for the HU. Confused maybe, not reading this 2 or 3 times definitely.


Your right though, he can either.

Run front and rear and use the LPF.

or

Run the sub out to splitters.


I would do the latter and run a second amp for new highs. Factory speakers suck regardless, and are easily overpowered with bass.