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lithium

Infinite baffle and cutting rear seat back

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I would like to run an IB sub (ski pass) setup in my new vehicle (2015 honda accord coupe) but I'm unsure if its a smart idea to cut the rear seat back. In previous vehicles w/ a 60/40 split rear seat I would lay down one of the rear seat sections. However, this vehicle the entire rear seat back is steel and does not have a split section that I can lower. Also, there is no pocket arm rest in the center like most sedans which people commonly vent through. 

  • Can I remove a section of metal and vent through the foam/leather seat? 
    • For low frequencies I think I would be fine... 
  • How much metal should I remove? 
    • Some percentage of SD? 
  • Are there any safety concerns I should have when removing some of this metal? 
    • passenger safety? (who actually has passengers in a coupe :)
    • I assume the function of steel is noise barrier and maybe some fire barrier? 

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I've done several different IB setups.  That metal is part of the structure of your car, as is the rear deck.  I would not touch any of that unless you are certain you can add that structure back in.  That being said, that panel is actually a blessing.  IT's more than likely giving you an ideal seal between the trunk and the cabin.  If you have a  rear deck, you can use this to your advantage by building a manifold, or baffle and letting the air from one side of the drivers filter through here, while the other side of the wave just meanders it's way 180 out.

 

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Post some pics so we can see what you're working with and what are your plans so far driver wise?

 

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I forgot to mention that the rear seat does lie down unlike other coupes I've seen. So I think its not structural, thoughts? 

The issue with the rear deck is that it's very narrow, roughly 12". Stock sub installed in the rear deck  is 8 inches with two additional holes for 6.5" drivers. 

Current driver options that I own are my Mach 5 MJ18 and  12" AA Arsenal. Making the MJ18 fit in a car is rough, I'd probably grab a 15" IB sub option just save myself the hassle. 

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I'll get some pics when I can. Here is a stock photo of the rear seat. As you can see, its one section. 

2015 Honda Accord EX-L w/Navigation Coupe Rear Passenger Seats

 

stock photo of the truck

 

 

 

image.png

Edited by lithium

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SO the steel you're thinking about cutting is the actual seat back?

 

If it were me, I would build a wall straight down from the back of the deck.  That gives you your front/rear separation and allows it to vent through the rear deck when the seat is up. 

I would be simple enough to fab up a baffle and seal it with some hot glue and clay to get an idea.  If you like it, then work to make it permanent.

 

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4 hours ago, Tirefryr said:

SO the steel you're thinking about cutting is the actual seat back?

 

If it were me, I would build a wall straight down from the back of the deck.  That gives you your front/rear separation and allows it to vent through the rear deck when the seat is up. 

I would be simple enough to fab up a baffle and seal it with some hot glue and clay to get an idea.  If you like it, then work to make it permanent.

 

Ya that's right. Cutting the actual seat back. I would cut a small hole and let the sub vent into the seat foam. 

The problem with the rear deck is creating that baffle. The actual deck is <12"  and I have to deal with the lid tension bars. I'll get pictures. Its useless to talk about this without showing you what it looks like. 

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So as you can see here the rear deck is about 12 or 13 wide between the bracing. 

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seat up (this color combo is kinda fuggly in some lighting, should have went with black interior lol) 

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seat down, opening is about 27 inch wide at the bottom, 16 inches wide at the top, 30 inches wide in the middle, and 16 inches tall. 

1SVAxLO.jpg

Edited by lithium

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Maybe three 10s or 12 IB on the rear deck could happen.

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3 dayton ultimax 10's vs my MJ18 in 15 cuft. MJ 18 on 300 watts vs 600 watts on the daytons.  (the mj18 xmax is 12mm so it actually runs out well below 300 watts) 

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Edited by lithium

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I'd rather see what you can fire through the rear speaker holes.

 

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I think I could make 3x 10" work on the rear deck. Seems like the Daytons, modelled above, could get close to the same performance as the mach 5 mj18 I've run in my last vehicles. 

I need to see if 12s could fit. And if they do, would the stock speaker openings in the deck be large enough to vent through. 

Im sure I could build a 6 inch thick baffle to install any size woofer on the rear deck. But that would defeat the purpose of the install. 

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Do you have the ability or desire to cut and weld on the deck?

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I don't want to cut the deck and do not have access to a welder. Still working out of my 1 bedroom apartment for now. 

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I hate to say it, but I think a small driver and enclosure is best for you at this time.

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4 minutes ago, Tirefryr said:

I hate to say it, but I think a small driver and enclosure is best for you at this time.

do you think stock opening in the rear deck would be too restrictive for 10s or 12s? 

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I am concerned with the loading and it how it can easily wipe away all the neat advantages you are trying to gain.  

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33 minutes ago, ///M5 said:

I am concerned with the loading and it how it can easily wipe away all the neat advantages you are trying to gain.  

That's fair. I'd rather cut the seat than the rear deck, but for now I'll probably try my 12" AA Arsenal sealed. 

Front stage is bit more important to me anyways. Planning to start with a simple two way with SSA components since I have a set just lying around. I'll probably get bored of that after a year or so and try some weird midbass stuff (underseat, kick panel, etc). 

Edited by lithium

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I was looking at the replacement seat back part and noticed circles on the drawing. Turns out there are about 36 holes on the panel. I'm going to build a sealed enclosure for one of my subs and see how much bass pass through the rear seat as is. 

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I’ve cut seat backs for IB and it made zero difference.

I’ve also cut rear decks, PITA and it’s rarely ideal.  Plus you lose the trunk lid torsion bar, which trust me you’ll miss.

I’ve never used an IB manifold through the rear deck factory speaker opening.  I think this would work well.

Here is an example.

 

C78762D7-9CAD-488C-974E-146F93FCB1C1.jpeg

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