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Hello all...

I just did this upgrade to my 2014 i-Touring hatchback yesterday, and the result was amazing. This upgrade will be the most cost effective and stealthiest looking, and the sound will be loud and clear throughout the whole spectrum, unlike the typical amp and sub install. I was under a time constrain so I couldn't take any pic at all.. sorry... but I'll try my best to describe the process and details...
Before I begin, I'd like to point out that there is a particular member on here that would love to jump in and tell me what I did was wrong, what I did would upset the balance of the universe,,,,blah blah blah... Either he's terribly misinformed about car audio fundamentals, or he's trying to impress ppl that don't give a crap by trying to sound scientific,,, but in reality, it's all cow dung... Whatever the case, ignore him.

What you'll need:

A pair of decent 3/4" or 1" tweeters. Mine is Polk db1001. Try to stay away from those $4.99 piezo specials...

A 4-channel amp with built-in hi-pass and low-pass crossovers, speaker level input is a plus. Mine is a Kicker DX200.4

A 4-ohm subwoofer of your choice. Try to get one that comes with the enclosure, that way you know they're perfectly mated. Mine is a Polk DXi108 (It's actually a DVC, each coil is 4-ohm,,, I'm using only one of the two coils)

Wires, RCA calbles, connectors, zip ties..... etc...

TWEETERS:
Pop off those triangular grills on top of the dash with a panel popper (those blue ones from Harbor Freight work just fine).. Underneath you'll find a plastic blank panel that shapes like a 3 1/2 in speaker... You'll need a very short Phillips head or one of those right angle drivers... Take those plastic blanks off, cut an opening (with a hole saw) that will allow you to flush mount your tweeters on. You can try to surface mount the tweeters, but it may not clear the grill....
To run the wires, just use a giant 36" zip tie (with the head cut off) as a puller. You can get these at Harbor Freight or Home Depot.. Don't forget to use the passive crossovers that came with the tweeters..
Sure, the tweeters point straight up, but the windshield should reflect those high frequency notes nicely.
For the driver's side tweeter, add a speaker wire extension and run under the dash, across over to the passenger side,, and end it somewhere in the passenger kick panel.
For the passenger's side tweeter, run the wire down to the same location,,, this passenger kick panel will be your "rendevous" spot.

REMOVE THE FACTORY STEREO:
The air vents and that horizontal fake wood panel just below it, that runs over to above the glove box, is one piece.... remove this assembly with your blue panel popper... Use your head, and don't fight physics... It should come off without any issue.. Unplug the hazard light harness,,, set this assembly aside...
Take off the single 10mm bolt. The stereo should slide out easily. Go ahead and unplug the 4 harnesses/plugs on the back of the stereo... The biggest harness is the only harness we'll need to work on.

CUT THE 8 SPEAKER WIRES:
Use a blade and CAREFULLY cut away the electrical tape/flex loom to expose about 6-7 inches of wires... Again, use your head and CONTROL your cutting force... Don't worry, it's not quite neural surgery..
At this point, you have 2 options:
A. Use a Metra 70-7903 or equivalent harness as a guide to which 8 speaker wires to cut.
B. There's a row of 8 wires on that harness... those are it.... polarity alternates ( + - + - .....),, You can then use a 1.5V alkaline battery to pop the speakers... As far as polarities, you can get a helper with a flash light to look at the cone direction, if it moves away from the magnet, you got the polarity right...

Make the cut at about the half way point of the exposed portion... Now you'll need speaker wires....

RUN 4 SPEAKER WIRES TO PASSENGER KICK PANEL AND 4 MORE TO UNDER FRONT PASSENGER SEAT.
If you're using a 4-channel Line Out Converter, put it at the passenger kick panel or the area just above it.. Run 4 speaker wires from the output of the stock stereo to the passenger kick panel. Make sure you label your channels (LF,RF,LR,RR)...It helps a lot if you remove the glove box..(Squeeze in the 2 stoppers to partially release it, then pry off the shock absorber thingey with a flat head..If your 4-channel amp has speaker level input, you can skip this and run these 4 speaker wires all the way to under the seat, where your amp will sit... I used a Scosche LOC.... I feel that you have a bit more adjustment by using a LOC...
Now run 4 more speaker wires from the other side of the cut... to under the seat, again, label your channel (but you can always pop your speakers later, if you don't label them)....
Now run the front and rear RCA wires from the LOC to under the seat..

RUN A REMOTE AMP TURN ON WIRE:
Run a single wire for your amp turn on. Tap it onto the gray wire (double check with a volt meter, this wire should turn on and off with ACC)... This wire is very thin. What I did was to expose the wire (1/4" or so) and wrap your wire around it, squeeze it nicely with a needle nose, tape it, then zip tie it... Add an in-line fuse (2-5 A) at kick panel location (in case you need to service it later)... Run this wire to under the seat..

BATTERY WIRE:
You can pierce through the big rubber grommet where a bunch of factory wires run through the firewall... I used the giant zip tie puller, and didn't have to remove the battery...A nice 8 gauge will be adaquate,,, I used a Stinger 10 gauge... now run this wire across to the passenger side together with the left tweeter wire...

GROUND WIRE:
You can ground your amp to a spot underneath the runner panel (not sure of the correct name)... Make your you sand all the paint off, then maybe coat the whole thing with silicon to prevent rust later....

SUB WIRE:
Run a nice gauge subwoofer speaker wire from under the seat to the trunk/hatch area.

SPEAKER CONFIGURATION:
Left tweeter, front left stock speaker, rear left stock speaker are joined together in parallel, and hooked to front left output from the amp. Right tweeter, front right stock speaker, rear right stock speaker are joined together in parallel, and hooked to front right output from the amp... Your tweeter wires should tap into the front speakers at the kick panel area...
Your sub will connect to the bridged output of the remaining 2 rear channels... It's important that your sub is 4 ohms or higher.. My Polk DXi108 is a DVC woofer connected in parallel resulting in a 2 ohm load,,, I had to remove the terminal cup and cut off one wire... It's now running only one coil...for a perfect 4 ohm load.. You can connect the 2 coils in series to make an 8 ohm load, but the sub will only get half the power from the amp...

CROSSOVERS, BASS BOOST, AND GAIN ADJUSTMENTS:
Go ahead and turn on the HIGH PASS FILTER for the front channels on your amp. If the frequency is adjustable, 80-100 Hz is a good place to start... Then turn on the LOW PASS FILTER FOR THE REAR CHANNEL, 70-80 Hz sounds about right... If your amp has the bass boost feature for the rear channel, use it.. it usually boosts at 40-50 Hz, much better than your bass adjustment on the stock stereo, which I'm guessing is at aroung 100 Hz,,, BAD...
Now play around with the gain adjustments on your amp, as well as level controls on your LOC... Find that perfect balance between background hiss (with volume all the way down) and the sensation of a powerful system...


All wires to the amp, I ran them under the carpet, in front of the seat, over that ledge, and out to a carpet opening around a vent/heater output plastic duct. Didn't have to unbolt a single seat bolt.... Now, add the fuse at the battery, hook up your sub, make some adjustment and enjoy.
 

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Good write up and install. I have been thinking of doing something simular to this but I heard there was a factory amp in the passenger kick panel even for the non-bose system. If there is that would eliminate the need to remove the radio and catch the speaker wires down there for the LOC.
 
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