2009 Legacy Subwoofer install. HK System.

[Neodeus]

Hello,

 

For the longest time I have had a good amp lying around that I used to use in a subwoofer system in a Jeep Grand Cherokee we used to have. Recently I have been getting the car audio itch and decided I wanted to install it in our 09 Legacy. This Legacy DOES have the HK system in it. I believe I have gotten most of what I need to do the install for it, but I do have a few questions.

 

1 - Any "gotchas" in running the power wire from battery to trunk? Any advice to make that process easier?

 

2 - What is a good spot to ground in the trunk?

 

3 - I am using Line Output Converters to get music signal to the amp. I am not replacing the head unit or speakers or anything in the car. What is the least painful speaker to tap in the car for signal? I know there is a subwoofer in the back already, but it looks like it's mounted up side down, and the wire to it is obscured, I am guessing under the rear deck panel behind the seats? I looked at how this comes off and it looks to be fairly involved. I was thinking maybe one of the speakers in the back door, but that panel also looks to be a pit of a pain to get off. The door handle (opener) looks to be the worst part with cables and such.. I can just see me never getting that back on right... Also, I know the HK amp is under the front passenger seat (I think). I believe I can tap off the subwoofer signal there, but is that wiring harness hard to get at? Would I have to loosen or remove the seat? How hard is that to get back in!??!

 

I would say my biggest hurdle so far is just getting that speaker signal to the amp.

 

Also, I have a 5 farrad capacitor. Would anyone recommend installing that too? Someone on reddit said they are useless, but it's just sitting around. Worth it at all, or no?

 

Thanks in advance!

[Neodeus]

I'M GONNA DO IT!!!........

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.....

Bump.

[Tehnation]

I just ran a new 1/0 gauge wire... the 1st time I had the wheels on and I ran it through the fender and then through the driver door. But that was a big waste of time, fast forward to now I ran it through the fender and then through a big oval grommet behind the fender liner. You have to of course remove the front driver wheel and fender liner, and it's right there, pop the grommet make a slit on the line, it seems that the extra space is intentional for extra wires. Then feed it through, it will come out behind clutch pedal or somewhere in that area, I snaked it along the driver side under the carpet, under the back seat and into the trunk. easy cheesy.

[Tehnation]

there are tons of things in the trunk to ground to, just remove the side carpet panel pieces and you will see a nut and bolt somewhere. Pick what's convenient or makes sense to your setup, you can go either left or right side, it's all part of the metal body, so anywhere is fine.

[Tehnation]

I used

 

https://www.crutchfield.com/p_142SLC4/Scosche-SLC4-Line-Output-Converter.html

 

and shoved it below the radio. If you search on here there is a diagram, thread or post which tells you which wires in the back of the radio are what. I just cut the wires behind the radio, instead of running around chasing wires in different locations, all the wires are right there, run them straight to converter, then run rcas under carpet in center column then to the back under the rear seats and then into the trunk. Just open your trunk and pop off the back seat, just needs force and it comes out. Then you should be able to see exactly what i'm talking about.

[Tehnation]

I think the subwoofer is under the driver seat, there is a write up on how to convert that one to rca as well. I'm not really sure, tossing that shit in the garbage was like one the first things I did when I got the car.

[Tehnation]

with this kind of setup, you can use your stock radio like normal, balance/fade, volume, eq, etc. as long as you have a 4 channel amp, or 5 channel if your running a sub as well. I run two separeate amps, and use a distribution block to split the power for my fuel pump, and two amps, with two extra two spare, for whatever in the future.

 

https://www.amazon.com/gp/product/B07RVJQFY7/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

[Neodeus]

Thanks for the info. I think with the regular stereo there is a sub under the seat and wiring to the back of the stereo is ok, because that is where the speaker harnesses plug in. My car has the Harmon Karden (spelling) system in it, however, and I believe this means there is an amp under the passenger seat. This amp controls the different speaker and the sub which is under the deck lid behind the back seat. With this setup I may be forced to tap the line output converters somewhere other than the back of the stereo. I may be wrong, however. Maybe I can still tap it off of the stereo. That would probably be easier than my other options.

[Tehnation]

oh! my bad! i didn't know the hk had a seperate amp. does the radio have pre amp outputs?

[Neodeus]

Quick question. I was looking around the engine bay and right in front of the driver area on the firewall there is a large grommet with nothing going in to it. It's kind of diamond shaped with soft edges. Do you know what this is plugging up? Can wire be run through it?

 

[Tehnation]

you can use that if you have an automatic, its where the clutch master cylinder goes.

[jherbo]

no clue if anyone on this is still active but does anyone know how to remove the OEM sub in the rear deck if you have the HK system?

[m sprank]

Remove the rear deck cover.  Its a pain in the ass.  Must remove back seats to access.  Chances are some clip or plastic retaining mechanism is going to break when you pull it.  UV, age, etc.  Last time I pulled a rear deck was 2018.