[WingNut81]

My 21 Sport worked just fine with the factory subwoofer wires going directly into my Kicker CX400.1 amp and later into my LC2i Pro. No limp mode or anything weird.

No issues with the LC2i Pro what-so-ever. Just had to tune it with the factory sub gain setting at max. I also ran a remote lead from the fuse panel instead of using GTO. Auto turn-ons have always been fussy for me over the years.

 

[Border411]

Ok folks... So here is an update. On a whim I connected my OEM subwoofer in parallel to the wires going into the LC2. Sure enough, it worked! This leads me to believe that the OEM HU is going into a limp mode as it doesn't see enough load to send a full signal. I will set up like that and report back.

 

[BrandonP]

I did the "tried and true" 8 inch Kicker CompRT in the OEM box with a 300w Kicker amp. The combo vibrated the living hell out of the back wall. The center seat belt reel was buzzing like crazy. I tried to track down and silence all the vibrations only to find out the OEM box itself was vibrating. IMO...300 watts is just too much awesomeness for the OEM box. It was loud and pounded like an angry caveman, but I hate vibrations.

I swapped to the 4ohm 8" Kicker Solo Baric L7T loaded box from Kicker and put it under the rear seat. The sound quality is so much better with NO vibrations. The box fits perfectly under the rear seat and really doesn't take up that much room. It's easily removable if you need the space. I did my wiring in such a way that if I need to remove the Kicker box for more room I can quickly pull off the underseat trim, unplug the signal to the LC2i and plug it into the factory wiring to utilize my factory sub. When I'm done I can put the Kicker box back in. Super easy 30 second swap.

I just did the LC2i Pro as I found the factory bass rolled off at volume level 21 and above. I'd recommend setting your accubass with the factory sub level maxed out. I had very odd issues and realized I set the accubass with the sub setting in the middle.

Grab your 12v, remote and ground right at the amp...as mentioned...cheap distribution block. Just put a 1-3 amp fuse on the remote wire as mentioned in the LC2i instructions.

GTO works, but a dedicated remote wire works better. You can get an "Add-a-Fuse" for less than $10 and run a line from the fuse box under the steering wheel.

The easiest way through the firewall (for me) is the hood release cable grommet.

Just a few thoughts from my recent experience with adding a sub. Your mileage may vary.

Can you post a pic of the Kicker L7t installed under the seat? I’m debating on running two of them under my seat if it can fit

 

[DeeDigidy]

My 21 Sport worked just fine with the factory subwoofer wires going directly into my Kicker CX400.1 amp and later into my LC2i Pro. No limp mode or anything weird.

No issues with the LC2i Pro what-so-ever. Just had to tune it with the factory sub gain setting at max. I also ran a remote lead from the fuse panel instead of using GTO. Auto turn-ons have always been fussy for me over the years.

Can you tell me where on the fuse panel did you tap the remote lead?

 

[gti16vman]

I tapped the ACC fuse under the dash. The top row of fuses, 3rd position from the right.

 

[WhippetGood]

I did the "tried and true" 8 inch Kicker CompRT in the OEM box with a 300w Kicker amp. The combo vibrated the living hell out of the back wall. The center seat belt reel was buzzing like crazy. I tried to track down and silence all the vibrations only to find out the OEM box itself was vibrating. IMO...300 watts is just too much awesomeness for the OEM box. It was loud and pounded like an angry caveman, but I hate vibrations.

I swapped to the 4ohm 8" Kicker Solo Baric L7T loaded box from Kicker and put it under the rear seat. The sound quality is so much better with NO vibrations. The box fits perfectly under the rear seat and really doesn't take up that much room. It's easily removable if you need the space. I did my wiring in such a way that if I need to remove the Kicker box for more room I can quickly pull off the underseat trim, unplug the signal to the LC2i and plug it into the factory wiring to utilize my factory sub. When I'm done I can put the Kicker box back in. Super easy 30 second swap.

I just did the LC2i Pro as I found the factory bass rolled off at volume level 21 and above. I'd recommend setting your accubass with the factory sub level maxed out. I had very odd issues and realized I set the accubass with the sub setting in the middle.

Grab your 12v, remote and ground right at the amp...as mentioned...cheap distribution block. Just put a 1-3 amp fuse on the remote wire as mentioned in the LC2i instructions.

GTO works, but a dedicated remote wire works better. You can get an "Add-a-Fuse" for less than $10 and run a line from the fuse box under the steering wheel.

The easiest way through the firewall (for me) is the hood release cable grommet.

Just a few thoughts from my recent experience with adding a sub. Your mileage may vary.

Your post is several years old, but I'm going through this process now. Actually, my path to get here is similar to yours since I tried the ol' Kicker in the OEM box last year and it was terrible. This is in my 2017 RTL-E. This summer I ripped everything out and started over, and I got an LC2i. You said you noticed bass roll-off at volume 21. How did you determine that? By ear? I couldn't notice anything by hearing or gentle touching of my new 10" sub, so I broke out my multimeter to measure voltage out of the OEM sub speaker wires with nothing connected and by playing a 59Hz test tone. Results are shown in the image. I did this with the head unit subwoofer setting in the middle and at max, like you suggested. There is a strange dip at Volume 23 at the max sub setting (I measured twice to be sure). Also, maybe I'm getting old, but I'll never listen above about 24, so I stopped at 26. According to this, I'm not getting any roll-off in the range I tested, but I'm no expert and figured I'd ask someone who has done this before. Thanks for any insights!

 

[TriCamiguin]

Not sure about volume roll-off. I thought the main complaint was lack of bass below about 35Hz. Volume 26-28!.....Geeze.....I have never had my volume over 15.... usually 8 initially, 10 highway, 12 interstate.