[JaeReese]

New to the forum, but been following since I bought my ‘21 Elite in January 2022.

Lately I’ve been modding the factory sub speaker box by blending parts from an old Rockford Fosgate P300-12 box with the Honda factory one. Basically I took the amp off the RF box and shoved it in the Honda speaker box.
Cut a hole in the plastic

Drop in 300W two channel class D amp

Had to use the flattest side on the factory plastic speaker box to make it work and spent time with the dremel massaging the hole so it would fit.

Dropped in a Kicker 2ohm dual voice coil 8” sub with some poly-fil.

Pulled high level speaker wires through the hole and I pinched them with the amp and some foam. These will be used as inputs to the amp. Basically the Honda connector puts them in the box and I pulled them back out to feed sound to the amp.

Had to stop. Still waiting on speaker input wire harness from EBay to arrive so I can finish the wiring. Still have to wire the positive to the battery as well. More to follow when parts come in. Probably not a new idea, but I’m hoping that it sounds ok. I really didn’t want to lose any cargo space for the sake of a lil low end thump again.

 

[JaeReese]

Install done!!! No regrets, worth the effort. Sounds punchy at all volumes.

I need to run out and get something to encase the wires in. Looks messy right now.

Grounded the amp using the bolt in the upper right corner. It’s sandwiched between the sub box foot and the frame with a nut on top to hold it all in place.

temporarily 3m’d/velcro stripped the remote gain knob in place. Not quite ready to drill visible holes in my dash cluster.

A few notes:
1 - The head unit bass levels need to be on more than 3 for the amp to cycle on.
2 - It plays hard with plenty of resonance. Box is full of poly-fil and it didn’t dampen the vibrations. I added foam between trunk and license plate.
3 -The adjustment knob makes a difference. Not all songs sound good at the same bass level. It also sounds like it does it’s own thing without knob. Playing at a separate level from the volume knob until you match them up for the song.

So cheap and satisfying work. I’m no Tony Stark and this ain’t an iron man suit, but I did build it in a cave with a box of scraps!

 

[stevenD]

Nice work, I'm interested to hear how it sounds once you are done..

 

[JaeReese]

Me too. I noticed that the inside of the box didn’t have much volume. There is a lot of plastic webbing and bracing in there. I tried to compensate for that using the poly-fil.
My estimation has it hitting lower Hz but not all that loud.
Still waiting on parts. Vendor said they are on the way.

 

[Dbp_22SG]

I just went with alpine S65 component speakers both front and rear doors along with a alpine KTA 450 amp and Rockford p300 sub in my trailsport

 

[JaeReese]

I think I’m headed the component speaker direction soon. The next phase will probably have me cutting out part of the underfloor tray and making a custom box to fit by the spare tire. I would really hate to give up cargo space for speakers again like I did in my 14’ pilot touring.

 

[greenrogue89]

massaging the hole so it would fit.

I'm dying over here. Great install but what you said was hilarious. 😂

 

[JaeReese]

Thanks 😁.
It sounds about as good an 8” sub can sound in an small enclosed plastic box. If I get around to it I may design a 12” enclosed box for the same space in CAD. If it all works out, I can share the file and all anyone would have to do is send it to sendcutsend.com and assemble the parts on their own. I’ve been looking at the numbers and this would be a challenge to get the sub tuned between 35-40Hz with the space available.

What is life and it’s experiences without a little humor?

 

[greenrogue89]

Thanks 😁.
It sounds about as good an 8” sub can sound in an small enclosed plastic box. If I get around to it I may design a 12” enclosed box for the same space in CAD. If it all works out, I can share the file and all anyone would have to do is send it to sendcutsend.com and assemble the parts on their own. I’ve been looking at the numbers and this would be a challenge to get the sub tuned between 35-40Hz with the space available.

What is life and it’s experiences without a little humor?

I hope you do. I would like to put a bigger sub in there. But I'd like to use a Sundown Audio sub. The magnets on them are huge.

 

[storm303]

That's a cool idea. I tried swapping out some low profile drivers into the factory spot (a Pioneer and an Alpine) but never got the sound I wanted. I didn't try an external amp though, interesting.

I went with an add more approach rather than replace in the end. I've got the factory sub enabled and added a P300-8P self powered external enclosure (two 8" total) that taps off factory sub signal. The porting on the external enclosure produces lower bass that a typical 8", and running two 8" together gets a little lower still. I estimate the pair approaches the sound of perhaps one good deep 10". When I need the small space the P300-8P enclosure occupies, it comes out easily in about 30 seconds. I normally keep it strapped to the cargo area rubber floor mat. I made a wiring loom around the speaker taps, remote wire, and power cables to reinforce the connections and make it faster to get everything unhooked and out of the car. In the future I was planning to make a single point connection mid loom but this has worked good.

I like the compactness of what you have going though. Does the enclosure produce flutter or unwanted vibration? I got a bit of buzz even with polyfil in mine.

 

[JaeReese]

That's a cool idea. I tried swapping out some low profile drivers into the factory spot (a Pioneer and an Alpine) but never got the sound I wanted. I didn't try an external amp though, interesting.

I went with an add more approach rather than replace in the end. I've got the factory sub enabled and added a P300-8P self powered external enclosure (two 8" total) that taps off factory sub signal. The porting on the external enclosure produces lower bass that a typical 8", and running two 8" together gets a little lower still. I estimate the pair approaches the sound of perhaps one good deep 10". When I need the small space the P300-8P enclosure occupies, it comes out easily in about 30 seconds. I normally keep it strapped to the cargo area rubber floor mat. I made a wiring loom around the speaker taps, remote wire, and power cables to reinforce the connections and make it faster to get everything unhooked and out of the car. In the future I was planning to make a single point connection mid loom but this has worked good.

I like the compactness of what you have going though. Does the enclosure produce flutter or unwanted vibration? I got a bit of buzz even with polyfil in mine.

i had a buzz the first time or two I dropped it in. After about 6 trials of adjusting the amount of polyfil to get the sound right the buzz was gone. Also got pretty good at putting it in and out and fastening it down.

 

[JArcher21]

That's a cool idea. I tried swapping out some low profile drivers into the factory spot (a Pioneer and an Alpine) but never got the sound I wanted. I didn't try an external amp though, interesting.

I went with an add more approach rather than replace in the end. I've got the factory sub enabled and added a P300-8P self powered external enclosure (two 8" total) that taps off factory sub signal. The porting on the external enclosure produces lower bass that a typical 8", and running two 8" together gets a little lower still. I estimate the pair approaches the sound of perhaps one good deep 10". When I need the small space the P300-8P enclosure occupies, it comes out easily in about 30 seconds. I normally keep it strapped to the cargo area rubber floor mat. I made a wiring loom around the speaker taps, remote wire, and power cables to reinforce the connections and make it faster to get everything unhooked and out of the car. In the future I was planning to make a single point connection mid loom but this has worked good.

I like the compactness of what you have going though. Does the enclosure produce flutter or unwanted vibration? I got a bit of buzz even with polyfil in mine.

Do you have any pics of your setup?

 

[RJRPP]

Install done!!! No regrets, worth the effort. Sounds punchy at all volumes.
View attachment 15005
I need to run out and get something to encase the wires in. Looks messy right now.

View attachment 15006
Grounded the amp using the bolt in the upper right corner. It’s sandwiched between the sub box foot and the frame with a nut on top to hold it all in place.
View attachment 15007
temporarily 3m’d/velcro stripped the remote gain knob in place. Not quite ready to drill visible holes in my dash cluster.

A few notes:
1 - The head unit bass levels need to be on more than 3 for the amp to cycle on.
2 - It plays hard with plenty of resonance. Box is full of poly-fil and it didn’t dampen the vibrations. I added foam between trunk and license plate.
3 -The adjustment knob makes a difference. Not all songs sound good at the same bass level. It also sounds like it does it’s own thing without knob. Playing at a separate level from the volume knob until you match them up for the song.

So cheap and satisfying work. I’m no Tony Stark and this ain’t an iron man suit, but I did build it in a cave with a box of scraps!

 

[RJRPP]

Did you disconnect the ANC?

 

[JaeReese]

Yes. I did that when I took the dash apart to put in the blue LEDs and plug in the lighted running boards. Sry I left that out. I was not sure if enhancing the factory system would interfere with it.