2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install

SATX_Si

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Hi all,
Like many of you I find the stock Si audio system lacks bass, and set out to improve it. Thanks to all of you who have posted your Honda Audio discoveries as they helped me out A LOT! Here's my contribution, and I hope y'all find it useful. Goal was to add good clean bass using parts I had on hand, and buying only what was necessary. I did all this work early in 2020 before the AXXESS DSP and amp bypass connectors were available.
Note: This post is not all inclusive, and assumes one already has some basic car audio installation experience. I aimed to expand upon what others have already done and how I went about improving the Premium Audio system's bass. This factory system is a PITA to modify and upgrade. Wish the head unit had pre-outs.

Amp Power and Ground Wires:
I pulled the battery and ran my 8 AWG OFC power wire through the big rubber boot in the firewall. There are a ton of wires in it so don't poke a hole in it! I unwrapped the black tape on each end of the boot, and that gave a ton of wiggle room to fish the cable through. 4AWG would fit easily. I used new electrical tape to seal the boot back up inside the car and in the engine bay. Easy, much safer, and less cursing than poking a hole in it!
I attached the power wire to the fuse box since the +battery terminal has a plastic cover that got in the way. I mounted the fuse block with a homemade bracket, and used a rivet nut in an existing hole between the shock tower and fuse box. The ground wire was attached in the trunk above the driver side wheel well.

Getting a signal:
Thanks to ScopeSys(?) and others for their hard work sorting out the signals our factory amp outputs. Based on their research I knew I needed to tap the front door mid-bass signals and use an LC2i to achieve a decent signal for the subwoofer amp. Not wanting to cut the factory harness I bought an Acura RDX amp off of eBay that included the male 18pin connector with maybe 3 inches of wire left on it. I de-soldered the female 18pin from the amp's circuit board and made my own straight through harness with a "Y" for the front right and left door woofer wires. I ran those 4 wires to my LC2i with a 9-wire speed cable.

Mounting the amp and LC2i:
My JL Audio 250/1 is too large to fit under the front seats, and a Kicker Key500.1 sure would make life easier by taking the place of this amp and the LC2i while fitting under a front seat easily. Originally I mounted the amp and LC2i to the back of my DIY speakerbox, but this made it difficult to remove if I needed to haul stuff. Just this month I relocated those components to the back of the 60 side of the 60/40 split rear seat. The board is just 1/2" plywood I had on hand that is spray painted black. I lifted the seat carpet to gain access to the metal seatback and drilled 6 holes for M5 rivet nuts. Be careful when drilling and go slow so you don't accidentally punch through the metal so quickly the drill pops through your seat fabric!
I drilled tons of holes in the board for cable management zip ties taking cues from Dean and Fernando at Five Star Car Stereo. There's enough slack in the wiring to flip the seat up and down if needed, and the components are far enough left that I can fit 8ft long 2x6's into the car without scraping them up, lol!

Subwoofer:
I had this Kenwood 12" laying around and a bunch of plywood, so I made a .9 cu/ft sealed box with a double thick front baffle. All the edges are rabbeted so it is glued and brad nailed together. I'll carpet it in the future. It meets my needs for now and makes stuff rattle!
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SATX_Si

SATX_Si

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Getting a signal:

Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200508_200844083


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200508_200855096


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200508_200950729


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200508_202624008


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200517_112232077


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200517_112235445


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200517_112245488


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200517_113012258
 
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SATX_Si

SATX_Si

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Mounting the amp and LC2i:

Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200412_111949713


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200412_111958181


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200412_112032408


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20200412_112038138


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20210421_144254290


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20210421_153123374


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20210421_162039151


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20210422_170151522


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20210422_180617875


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install IMG_20210422_180801722
 


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SATX_Si

SATX_Si

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Little update. The Insta algorithm got me good with a Skar Audio ad for fiberglass sub box for the Civic Sedan. Checked the price and reviews and bought the 12" version that night. Packaging was superb, and arrived no damage. I installed it and been listening to it for a couple weeks now, and it sounds great. Love the corner loaded bass!
The main downside to this enclosure is how it mounts to the car. It only has the one mounting hole up top and a plastic push rivet to go through the factory push rivet hole. I noticed it was backing out, so decided to mount it with real hardware.
I drilled out 2 factory push rivet holes to fit 5/16-18 rivet nuts aka nut-sert(?), and drilled a hole thru the back of the box. I shoe-goo'd large washers inside and out of the new hole for strength and put a layer of butyl sound mat over them. Re-installed and it is SOLID! Now I can take corners without worrying if this box will come loose.
For those wanting a fiberglass box to maximize trunk space, this is a no brainer.

Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_203505083


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_183535268


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_183742477


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_185456996


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_190005256


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_195330944


Honda Civic 10th gen 2019 Si Sedan: Sub, amp, LC2i, power/ground/signal wire install PXL_20240310_203305054.MP
 

Enzym

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These are very beautiful lips :p! nice setup!
 
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SATX_Si

SATX_Si

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Uhhhh, thank you very much🤣
 

Estocker1981

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And it looks like you still have full access to the donut, right? I'm gonna have to pull the trigger on this purchase, I think. Thanks for the update!
 


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SATX_Si

SATX_Si

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The Si Sedan does not have a donut due to the center exhaust and different trunk floor pan. Might want to double check with Skar to see if this fits the non-Si sedan as well. I think the donut trunk pan has molded foam block spacers on the right and left to make up the height difference.
 
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SATX_Si

SATX_Si

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Just checked the Skar website, and looks like these enclosures fit any 10th Gen Civic Sedan. Happy shopping!
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