Wiring for a new sub..

[ChrisInSeattle]

I hope this isn't an old topic... But how do you wire up a new sub?

Since the sub has it's own amp (?), are the inputs line level? Can I simply connect those to line-level inputs on my amp? Something more complex? Can I get those inputs at the amp socket in the back, or do I have to look at something on the head unit?

How does the sub button work? Does it simply toggle power to the sub? (i.e., could I run power control line from the socket in the back to my amp?

Essentially, I'm hoping that I can get amp inputs, and a working sub button by simply jacking into the wiring harness below the stock amp, and I'm waiting to be told how it's nowhere near that simple.

[socalboo]

I assume you are talking about the stock sub

From what I can tell from the .pdf wiring diagram on one of the stickies above, as well as the sub switch I pulled out and shipped off, the sub switch is nothing more than a toggle on the 12v amp lead (usually blue wire, but not the power antennae lead). The out line from the switch looks like it is one of the wires that goes into the sub plug beneath the sub mount, so that would support that notion. The sub switch is simple plug with two lines...so I can't see it working any other way than just an on/off function, where you depress the button to connect the two wires ("on") and depress again to disconnect the two wires ("off"). Made me kind of sick to see how simple it was and how much they charge for it.

The stock sub has line level inputs.

The rear channel off the stock stereo runs the NEXT headliner speakers, line levels to sub, and the rear pillar speakers (at least according to the .pdf stereo wiring diagram and .pdf electrical diagram).

As for where to pick up the wires, it looked consistent to me when I pulled the fjammer out, but about 10 minutes of exploration should give you your answer.

You can tap the line level input for the sub off the switch, but you've still got to pull line level from the HU (but the sub plug will give you those).

Personally, I would ditch the entire stock wiring, save the switch if that is important to you, and run new wires. the power wire back to the stock sub is piddly small, and I didn't see any grounding nearby, which leads me to believe the ground runs back up through the harness to frame tap, about a foot and a half from the battery. not good if your amp pulls many amps. you could easily pull off a little paint around the stock sub mounting bolts, put on a crimp on or solder on ring connector to a beefier ground wire, and attach it with a 1/2 inch 10mm bolt. You will be much better off. If you are using stock head unit, you might think about some decent quality rca line level converters, shielded rca cables, and run them to the new sub. If you've got an replacement HU with sub out, rcas are always the way to go.

Didn't you have some bomber system in your FJ, or am I just confusing you with someone else?

[ChrisInSeattle]

I wasn't clear.

What I have now is a stock FJammer and the stock sub. I'm ditching the stock sub and hooking up a new one, with its own amp. So, the basic question is how do I get line level inputs from the FJammer into the new amp?

My question is assuming that there are seperate outputs for the sub. But maybe that's not the case and the crossover just takes place in the sub itself? So I can use the same speaker level inputs that I use from the speaker amp?

[socalboo]

ChrisInSeattle previously said:

I wasn't clear.

What I have now is a stock FJammer and the stock sub. I'm ditching the stock sub and hooking up a new one, with its own amp. So, the basic question is how do I get line level inputs from the FJammer into the new amp?

My question is assuming that there are seperate outputs for the sub. But maybe that's not the case and the crossover just takes place in the sub itself? So I can use the same speaker level inputs that I use from the speaker amp?

Sorry, but your response raised some more questions, namely the crossover reference.

To get line level inputs to Fjammer, you can use the wires off the sub harness under the right wheel well panel cover, or you can tap off them any time all the way up to the deck. The main questions is whether you are going to get any noise/whine from using line level inputs. I'd do it in this order:

1. hook amp up with speaker wire from sub harness. if no noise/whine, you are good to
2. if whine/noise, I'd just drop thick guage speaker wire temporarily back to the amp in the rear (literally resting on top of the seats...it is just to test the new amp). If no noise/whine, then I'd take the time to run the wires back so they would be hidden. But if noise/whine....
3. get quality line level converter to RCA (I assume your new sub amp can take RCA) and get some quality shielded RCA cables, run them back temporarily and test. if you've still got noise/whine, you should then address power leads and grounding.

I would avoid using power lead off sub harness. small guage wire. stock amp only 2x30 watts, so doesn't use much. You can tap the bottom 10mm bolt on the bottom sub mount right next to the harness if needed for ground (might need to scuff up a little to get good ground).

There is no separate lines from the back of the fjammer to the sub. there are front channel, left right, positive negative, and same for rear channel. the front dash and door speakers tap or splice off the front pairs, and the rear pillars, NEXT headliner speakers and sub splice off the rear pairs. You'll note that the speakers you pull out all say 2ohm on them. That is because you've got multiple speakers running off one line 4 ohm line (I assuming the fjammer output is 4 ohm...that is what I read on a .pdf from a sticky here on the forum). The sub says 30w/2ohm x 2 on the rear of the magnet.

as for crossover, I've never seen one, despite pulling my fj apart significantly. any crossover that may exist for the stock sub is likely in the amp housing.

Yes, you could just use the same speaker level inputs you use from the speaker amp. If that amp has an rca pass through (most newer amps have this), you could just use these for the sub amp.

Hope that answers your questions.

[Prof T]

ChrisInSeattle previously said:

I wasn't clear.

What I have now is a stock FJammer and the stock sub. I'm ditching the stock sub and hooking up a new one, with its own amp. So, the basic question is how do I get line level inputs from the FJammer into the new amp?

My question is assuming that there are seperate outputs for the sub. But maybe that's not the case and the crossover just takes place in the sub itself? So I can use the same speaker level inputs that I use from the speaker amp?

Hope your new sub has a better amp then the stock one. What kind of "bazooka" are you putting in?

[fourx4ord]

Here is a thread that gives you the proper speaker connections for the sub

Installed Rear Speakers and Bazooka Tube

[ChrisInSeattle]

Prof T previously said:

Hope your new sub has a better amp then the stock one. What kind of "bazooka" are you putting in?

Noooo... no bazooka. I have an amp under the seat for 4 speakers, adding another on the other seat for a sub which will be in an FJCruiseraudio box.

I guess my question really boiled down to whether or not there was a low-frequency-only output from the FJammer (eventually ending at the subwoofer harness). Seeing as how that's not the case, the rest is easy enough.

[socalboo]

No, no 2v low level inputs available. Whew! You made it so simple third time out.

[Prof T]

socalboo previously said:

No, no 2v low level inputs available. Whew! You made it so simple third time out.

Can you post some pics of you install?

[ChrisInSeattle]

socalboo previously said:

No, no 2v low level inputs available. Whew! You made it so simple third time out.

Haha.. sorry 'bout that!