All right, finally finished everything today w/the rear subs while I was working on the back-up cam install. Still haven't made the amp rack, will work on it in a few weeks when time permits. I'll cover the actual fabbing of the rear seat, and generally how to wire up a Line Output Converter (LOC). If you're doing this install you should know how to run your amp power, remote lines, and ground before attempting. I am also skipping the "how to" on a sub box because I didn't take pictures and making a sub-box is it's own how-to write up...

Dimensions were roughly:
may be off by .75" in any direction, my brother just informed me he changed 2 of the dimensions because of a mistake he made. Either way it all came together and sealed nicely.

Started off with these dimensions:
33" x 12" (Face and Back-sub mounting holes centered ~7.75" away from sides)
12" x 5.5" Side panels (Mount FLUSH with all other panels-@ least they should have)
33" x 5.5" Top and Bottom

Total volume comes in around .78 cu. ft. If I had more expensive subs or larger subs mounted in there I would care more about the volume, but I don't and it sounds fine.

Tools Needed:
PAC-SNI35 Line Output Converter (~$28)
3ft+ RCA Left/Right channel ($12)
(2) RCA mono input dual channel output ($6)
(2) *sub of choice* I chose 8" Kicker C8's -cheap and replaceable, sound good too- ($62)
1 Sheet (usually comes in 36"x48") 3/4" MDF -medium density fiberboard- ($~20)
(4) L-shape metal mounting brackets ($4)
Silicone based sealant ($4)
10-14ga speaker wire ($~8)
Jigsaw/Table saw
Metal Grinder/cut-off saw
Self Tapping Screws
Sheet Plastic or Cardboard for template
Small Nails
Electrical Tape/3M scotch locks/Screw terminals
Ratchet w/appropriate size sockets (own a full set of metric and U.S.)
Offset/needle-nose pliers

1) Start with rear set folded DOWN and remove headrests. On the left and right sides find the (4) bolts holding the top and bottom halves together. Completely remove bolts and set aside.

2) Fold seat back and flat, flush with ground.

3) Use offset pliers or needle nose pliers to GENTLY depress flanges of plastic cable stay separating cable from steel frame.

4)Remove cable wire insets on both sides by pulling forward, then outwards and rear.


5) Set aside bottom half of seat, headrests, and bolts in a safe place.

6) Find zipper on bottom lip of seat back. The start/end of the zipper may be tucked up into fabric. Unzip.

7) Begin gently peeling and separating fabric from seat foam. There are velcro strip stays down the edging of the seat. When you hear ripping don't panic. Just keep moving slowly turning the seat inside-out.


8) This is what the seat should now look like. Prop it frame side up on a worktable or the ground. The cover will stay clean because it's inside out .


9) Take sheet plastic or cardboard and stencil out the frame. Mark the INSIDE lip dimensions.


10) I did a depth check by stabbing a pencil through the foam until I could feel it on the other side to get a rough idea for depth of the box.


11) Instead of removing the foam completely and turning a difficult task into an impossible one I simply flipped the "butt end" of the foam up vertically w/out breaking it. You need to rip the foam in a few spots to release them from the steel support lines. This way I could work on the frame with the foam out of the way.
12) The steel support lines need to be cut/grinded off. HOWEVER leave the top portions intact so that the cable stays remain on the leftover support lines. I electrical/ductaped them in place so they wouldn't slide off.

13) Slide the sub box into the frame rail in the up-right position.

14) Grab the 4 L-shaped steel mounting brackets and mark holes for the screws. Get your hands on some quality stainless self-tapping screws, or tap the holes with a small drillbit.

The best spot to mount the box to the frame is the square steel at the bottom of the seat.


You COULD mount the box to the actual round sub-frame but self-tapping screws would be near impossible to use and the sub-frame is much harder to get through. Also the flush flat surface mates much better with L brackets.
15) NOW COMES THE FUN PART
Start to rip all of that terrible crappy foam out! but do this very carefully or you'll end up with a giant PITA. Mark the outline of the box into the foam with the mounted box ON TOP. Then take scissors or a sharp knife (no longer than 7") and cut along the line trying not to completely go through the foam. With the bladed crease begin by hand to rip the foam out.You want to leave about a 1" layer between the back of the box and the seat back. Essentially you are hollowing out a spot for the sub box to rest in while maintaining a cushy back for your passengers. Also the fabric won't fit back over the seat and box if you have not removed enough foam. It's trial and error, I had to re-do my foaming 3 times before the seat cover fit back over it and zipped.

16) Now drill out holes for your speaker wire, or install a terminal. I hate terminals and the loss of current most are notorious for (and its one more thing to fail/pop out) I seal my holes w/silicone and duct-tape. Run enough length to reach your amp.
17) Now that the box is nestled into your foam pocket begin to turn the fabric right-side out again. Go 4" down on either side evenly and slowly to prevent tearing/catching on the box or hardware.

18) Take a screwdriver and stab 2 holes for your speaker wiring to come through. You can choose to do it on the sides, bottom, top, w.e. I chose the bottom because of where my amp will be mounted. Pull the wire through the holes.

19) When you reach the bottom you will most likely have to remove a good amount of foam more than you anticipated. Just be patient and make it fit right, DO NOT wrench on the zipper, it will break.

20) With everything zipped up and the speaker wire ready find the rough center of your mounting holes in the box. Again stab with a screwdriver and snip out the center with scissors. Leave ~.2" lip of fabric overlapping into the box.


21) Wire up the subs appropriately.

22) Mount subs into seat.

23) Now run steps 6-1 (reverse) mounting back of seat onto lower half.
24) Time to wire the LOC. Remove your stock sub(if applicable). And bolt-cut the upper mounting post, or all of them if you feel the need.

25) locate the 4-pin connector that was going into the sub box. Cut it off and strip all 4 wires.

26) THE WIRES ARE LINKED AS FOLLOWS- GREEN WIRES are negative- +GREY WIRES are positive+ Channels are separated by BLACK stripes and WHITE stripes.
The PAC-SNI35 has 4 lines. WHITE/GREY are channels, -BLACK stripe is negative- +NO stripe is positive+
Link all channels to their appropriate signal and channel.
The two left-over brown wires from the LOC are spliced together.

27) Link the LOC with the RCA's to the amp. If you have an amplifier that utilizes a dual-band Channel1+2 to 3+4 you will not need the mono-splitters. My amp keeps CH1+2 and 3+4 separate for all configurations. Basically using the splitters turns a 2 channel input into the 4 required.
28) Run your amplifier ground wire to the seatbelt!!! I tried the tailgate link and stop, BOTH are unreliable grounds.


29) Before putting in your amp fuse and firing everything up re-check all levels and crossover points, the PAC-LOC now comes with it's levels turned all the way down. DO NOT turn these levels past 1/2, it's unnecessary. Level match your amplifier, RCA's, and any equalizers once the system is up and running. Check all sub seals. Tune to your personal preference. Once everything is nice and tucked, ENJOY!


^Finished-except for relocating amp to amp rack-^

 

Cool idea.....How do the seats feel, I am sure there not as soft as before but at least they are still functional. Would have been pretty cool to keep the speakers hidden under the fabric, but I guess a thief will have a hell of a time removing them from where you put them so doesn't really matter if you can see them or not.

Great job nice write-up!!

 

Nice set-up ...Just a couple of questions though....

1) Are you getting any engine noise coming from your speakers?

2) Does the LOC & amp only amplify the subs..The front & sound bar speakers are not affected/enhanced. Are they only powered by the stock unit?

3) The brown wires are not being used, is that the reason why they are connected to each other rather then grounded

Thank you.

 

The seats feel exactly the same - the foam that is removed is VERY dense stuff. Because the box is mounted to the frame the rigidity that the steel support lines provided is maintained.

If the speakers were mounted under the fabric you would get a fluffy poof of fabric when the subs hit, it would be funny but if you ever needed to do any maintenance on the sub/box it would be a pain to take the fabric all the way off again and have to unmount the back.

1) No engine noise. Engine noise is generally due to a bad ground, or from RCA lines that are poorly insulated (cheap knock off crap) that are run on the tub. RCA's will pick up electrical interference, vibrations, engine noise, etc. if they are poorly insulated no matter where you run them. Spend the extra $5 on good quality. -A bad ground is generally more likely to be at fault than the RCA's-

2) The LOC converts the analog speaker input from the main amp into a 4v low level output, it doesn't amplify per-say but you can adjust the output volume level. In my set-up the Amplifier ONLY powers the subs. If you wanted to you could get a 5-channel A/B amplifier and power all of the speakers in the car. However you would need dual voice coil subs and an amp that is stable in the final ohm rating the subs need. The only amps that I would consider with that kind of system cost upwards of $1000.

The BEST set-up in the Jeep IMO (there are lots of varying opinions on the best SQ) would be to run a 4 channel A/B amp in place of the stock infinity ran to an aftermarket head unit. Then a monoblock (1channel) D-class amplifier running 2 dual voice coil 8" subs @4ohm. If you level matched the amps correctly and took the time to modify the x-overs to compliment each other you could have a killer system for less than $500 (excluding the head unit). Using LOC's always compromises SQ because it is in effect translating and distorting an already crossed-over frequency from another amp.

3) The brown wires are grounded to each other. The PAC-manual states for some instances they actually do need to be grounded to the frame, but I have never needed to in any vehicle- I've put the SNI-35 in a few VW's, an accord, 2 Jeeps, Dodge charger and none of them ever needed the browns to ground to frame. If you get a dirty signal I'm assuming you need to ground to the frame.

 

Thanks for the reply ...May have to include that MOD in my list of things to do

 

Thanks for the reply and Great job in the install and info!!!

 

pretty cool!!!

 

chaulk up another mod to the list

 

Dose your seat still fold all the way forward OK without having to push your front seats to far up? Could you post up some picks of the seat tumbled forward? Great idea by the way and thanks for the detailed write-up. I will more than likely be doing this one soon. I have been looking for a solution for subs in my 2 door for a while and this is the best I have seen.

 

very nice