2018 Civic Si Sedan Subwoofer Upgrade

[IvanJonn]

No need to touch the head unit with the Rockford Fosgate that I linked to in my original reply. You can run the "high level" inputs directly from the stock sub wiring.

No need to touch the head unit with the Rockford Fosgate that I linked to in my original reply. You can run the "high level" inputs directly from the stock sub wiring.

Oh nice! That makes things much easier. The one I linked I believe is the same one except it's a 10 inch instead of 12 inch (don't really think I need extra large subwoofer as I'm not looking for crazy bass as I originally posted, just more clarity in the lower end) When they do the install could you link to me how they tapped into the wires? From what I've seen people get a plug adapter so you don't have to cut the factory wires.

Sponsored

 

[Sgtbaker420]

I'm thinking of buying this kit on eBay.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/390835586523
What do you think?

That's the one! The wiring is nice too. The description says that the 12v power line is 8 gauge. But when I opened mine up, it was 4 gauge. Nice bonus.

 

[Sgtbaker420]

That's the one! The wiring is nice too. The description says that the 12v power line is 8 gauge. But when I opened mine up, it was 4 gauge. Nice bonus.

The installer gave me two choices. Cut into the factory sub wires and use the "high level" inputs on the sub. This will not require touching the head unit or opening up any of the dash, but you "lose" the factory sub. OR you use a line adaptor out of the head unit and convert the signal to use the "low level" RCA inputs on the sub. I chose to cut the sub wiring. It should allow for more power distributed to the rest of the speakers, at the cost of losing the factory sub all together which IMO is complete garbage anyway.

 

[IvanJonn]

That's the one! The wiring is nice too. The description says that the 12v power line is 8 gauge. But when I opened mine up, it was 4 gauge. Nice bonus.

Oh nice! But if it did come with 8 it should be fine still right? Also I have a question: Earlier you mentioned an amp? I thought these have a built in amp? Or are you running another one?

 

[IvanJonn]

The installer gave me two choices. Cut into the factory sub wires and use the "high level" inputs on the sub. This will not require touching the head unit or opening up any of the dash, but you "lose" the factory sub. OR you use a line adaptor out of the head unit and convert the signal to use the "low level" RCA inputs on the sub. I chose to cut the sub wiring. It should allow for more power distributed to the rest of the speakers, at the cost of losing the factory sub all together which IMO is complete garbage anyway.

If by "lose" you mean that it won't get any signal, I agree anyways. Most of the bass seems to come from the door speakers anyways, as when I unplugged the subwoofer I barely heard a difference.

Do you know if there is a quality difference between using "high level" and "low level" inputs? I'm fairly new to this. I found these two adapters as well on eBay. One I could probably use for the high level, and the other for low level if I were to use the RCA connections. Check them out and let me know what you think.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/132276842953 <--- Low Level

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/391981243182 <--- High Level

 

[Sgtbaker420]

If by "lose" you mean that it won't get any signal, I agree anyways. Most of the bass seems to come from the door speakers anyways, as when I unplugged the subwoofer I barely heard a difference.

Do you know if there is a quality difference between using "high level" and "low level" inputs? I'm fairly new to this. I found these two adapters as well on eBay. One I could probably use for the high level, and the other for low level if I were to use the RCA connections. Check them out and let me know what you think.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/132276842953 <--- High Level

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/391981243182 <--- Low Level

I don't recall what amp I may have been referring to. I reread all the posts just now. But both the Cerwin Vega from the other poster and the Rockford Fosgate p300 I purchased and that you looked at on eBay have built in amplifiers. As far as the wiring goes, I'm not 100% sure but;

The research I did seems to show that there is very little to no difference in sound quality between the high level and low level RCA inputs.

If you use the high level inputs, you use the wire from next to the speaker as the line in. This saves messing around with the Head Unit but the factory speaker gets no input and is useless.

If you use the low level RCA inputs, you need to use a Line Out Converter BEFORE the factory amplifier and that requires you pull out the Head Unit.

...I think.

 

[IvanJonn]

I don't recall what amp I may have been referring to. I reread all the posts just now. But both the Cerwin Vega from the other poster and the Rockford Fosgate p300 I purchased and that you looked at on eBay have built in amplifiers. As far as the wiring goes, I'm not 100% sure but;

The research I did seems to show that there is very little to no difference in sound quality between the high level and low level RCA inputs.

If you use the high level inputs, you use the wire from next to the speaker as the line in. This saves messing around with the Head Unit but the factory speaker gets no input and is useless.

If you use the low level RCA inputs, you need to use a Line Out Converter BEFORE the factory amplifier and that requires you pull out the Head Unit.

...I think.

Alright! If there is no difference it looks like I'm just going to steal the signal from the factory subwoofer. Like I said, I agree with you. It does little to nothing in terms of what a sub-woofer (even as stock) should put out. It's seriously disappointing how they can call it a "Premium Sound System". I am happy with the other 9 speakers, it's just that dang subwoofer! And so, like I said before, would it be better to buy a plug adapter to take the signal from the wires connected to the subwoofer? To avoid cutting the factory wires altogether. I linked the adapters in a previous post above.

No. I got the Rockford Fosgate Punch. It's going in the trunk.

Right here haha! Unless you accidentally said Punch. Because I looked it up and that's a separate amp. But, never mind that! Just needed to clarify if your setup had a separate amplifier cause I knew the p300 has a built in one.

 

[Sgtbaker420]

Ah ha! Yes. Didn't know that was a separate product, thought that the P in P300 was for Punch.

As far as the adapters go, I can't help much. Maybe get both and return 'em if you don't need them? They're inexpensive.

 

[IvanJonn]

Ah ha! Yes. Didn't know that was a separate product, thought that the P in P300 was for Punch.

As far as the adapters go, I can't help much. Maybe get both and return 'em if you don't need them? They're inexpensive.

Haha! No worries! And I only put two adapters because one can plug into the back of the head unit to create an RCA output (for the low level), and the other one can plug straight into the plug that plugs into the subwoofer (high level) I would just buy this adapter if I were to do the high level route.
https://www.amazon.com/Metra-72-7800-Connector-Harnesses-Vehicles/dp/B0002BEPJY
Does that make sense? Cause it sounds to me that the shop you're going to is actually cutting the wire, when instead you can use this adapter to retain the factory wires.

 

[Sgtbaker420]

Here's a link to download a pdf of the manual.

http://rftech.custhelp.com/app/answers/detail/a_id/1070

The speaker input on the p300 has either RCA inputs or a special harness input that is connected to the speaker wires, I don't think either of your adapters will work. The harness for the high level inputs is included in the package.

 

[IvanJonn]

Here's a link to download a pdf of the manual.

http://rftech.custhelp.com/app/answers/detail/a_id/1070

The speaker input on the p300 has either RCA inputs or a special harness input that is connected to the speaker wires, I don't think either of your adapters will work. The harness for the high level inputs is included in the package.

Sorry! I think we might be getting confused. I had meant for that adapter to just provide two stray wires to splice the subwoofer into, instead of having to cut the factory wires. Because that's what you have to do right? Tap into the signal from the factory subwoofer plug? Let me know if I need to explain it better! (Also for some reason the link wasn't letting me see any manuals when I clicked on the 10 inch manual pdf)

 

[Sgtbaker420]

It's dumb, you have to click where it says [owners manual].

You don't use direct wires or RCA into the sub. It has an adapter. You'll see it.

 

[IvanJonn]

It's dumb, you have to click where it says [owners manual].

You don't use direct wires or RCA into the sub. It has an adapter. You'll see it.

Yup, clicked that and I get a "Page Not Found 404" LOL
And I'm trying to figure this out before I buy it... Since you have it would you be able to take a picture and show me?
https://www.civicx.com/threads/diy-install-subwoofer-in-non-touring-p300-10.5478/
This guy installed the same subwoofer into his EX-T (no subwoofer, had to tap into the rear deck speakers)
Can you point out what you're talking about with his thread?

 

[Sgtbaker420]

I'm not certain. Obviously one could tap into the existing wire like he did and still use the high level inputs AND keep the sub connected which would be great for resale. I don't know though, if one of the adapters you listed would help with that. Sorry mate!

 

[IvanJonn]

I'm not certain. Obviously one could tap into the existing wire like he did and still use the high level inputs AND keep the sub connected which would be great for resale. I don't know though, if one of the adapters you listed would help with that. Sorry mate!

I think I figured it out! While waiting for you to reply I started looking at install videos. That input plug right there has the wire you're talking about which has an RCA end. If you would install it to a factory system with the high level input, you just have to cut that included adapter you're talking about. Then I would just splice those two wires into the adapter I linked to as the input. Hope that makes sense! Do you think that will work?

Sponsored