# Subwoofer firing directly into the rear of the back seat



## cheesehead (Mar 20, 2007)

I am in the process of building a box for my new BM MKIII. It will be going into a 2003 Crew cab s-10. Due to very limited space the box I have designed will have the subwoofer firing directly into the rear of the back seat. Once I install the grill it will undoubtedly be pushing into the rear of the seat. What effects will this have on performance? I am sure others have had similar issues. What did you do?

Thanks


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## playedout (Feb 17, 2010)

...ok depending on what you are referring to as "crew cab" this could be remedied a few ways.....
if by crew cab you mean -two seats...single cab....no extension...

not sure if this will help you or not, but what we did on the 98 s-10 we recently did was took the seats out and with some measuring, tweaking, cutting, and playing round we were able to extend the box under the seat... we did it the hard way and went with sealed enclosure due to the subs we were using...

however the easier route would be to design an enclosure with a "slight" underseat kick that creates enough room for a couple tuned ports... as long as the grill guards you are using has enough space to allow for a full extension of the sub, and nothing is pressing against it......you should be fine taking careful consideration in how you tune your ports for maximum performance from your subs.....


if by "crew cab" you mean extended (back seats).....then there are TONS of options..lol

There is the Classic remedy to.....the Old Faithful "cut-through"..lol put them suckers in the bed and port em into the cab...hahaha (not for the faint of heart....lol)


dunno if that helps, but thats what we came up with.....


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## PorkCereal (Nov 24, 2009)

All the f150 screw guys are building boxes that upfire under the rear seats. You only need .5 cuft if i remember.


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## cheesehead (Mar 20, 2007)

playedout said:


> ...ok depending on what you are referring to as "crew cab" this could be remedied a few ways.....
> if by crew cab you mean -two seats...single cab....no extension...
> 
> not sure if this will help you or not, but what we did on the 98 s-10 we recently did was took the seats out and with some measuring, tweaking, cutting, and playing round we were able to extend the box under the seat... we did it the hard way and went with sealed enclosure due to the subs we were using...
> ...


Thanks for the reply!

Crew cab meaning 4 doors with the rear seat being a full seat. There is "some" room behind the seat but nothing under the seat. My plan was to build a wedge shaped box behind the seat. Between the cab wall and seat. I do not want to make any major modification to the truck. So no "blow through".:blush: 

Back to the question........ will firing the sub into the seat be a problem?


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## PorkCereal (Nov 24, 2009)

Will muffle the sound a slight bit. As long as nothing is touching on the sub, no.


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## playedout (Feb 17, 2010)

as i said ..as long as your grill guard doesnt interfere with the travel of your sub, you will be fine. 

are there reasons that you're not considering up firing or rear firing them? 
(just curious)


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## playedout (Feb 17, 2010)

ohhhh.FFS...i cant believe i read that three times and didnt catch the fact that you are wanting them BEHIND the REAR seat..im sorry brother..lol in THAT scenario..what ya got goin is your best run... remember the grill, and let me know how it sounds.....lol

sorry bout my crappy reading comprehension skills..lol (it is 8:30 am , havent been to bed yet from work..lol)


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## cubdenno (Nov 10, 2007)

playedout said:


> as i said ..as long as your grill guard doesnt interfere with the travel of your sub, you will be fine.
> 
> are there reasons that you're not considering up firing or rear firing them?
> (just curious)


He drives a 4 door crew cab. There is just a tiny amount of space behind the rear seats. No way in hell to upfire. No room under seats for a box either if I recall.

To OP:
If the seat material is cloth, there should be very little muffling of your subs. If leather/pleather/vinyl, you might have more depending on how much rap around the material does to the grill. Think using vinyl to seal up something.


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## cheesehead (Mar 20, 2007)

PorkCereal said:


> Will muffle the sound a slight bit. As long as nothing is touching on the sub, no.


I ordered the 12" grill from Madisound that was recommended in the BM MKIII thread. So nothing should be able to touch the sub. I figured it would probably muffle it some. I was just wondering if anyone had any experience doing it this way.


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## cheesehead (Mar 20, 2007)

playedout said:


> ohhhh.FFS...i cant believe i read that three times and didnt catch the fact that you are wanting them BEHIND the REAR seat..im sorry brother..lol in THAT scenario..what ya got goin is your best run... remember the grill, and let me know how it sounds.....lol
> 
> sorry bout my crappy reading comprehension skills..lol (it is 8:30 am , havent been to bed yet from work..lol)


No worries man!

Sorry the multi quote function doesn't seem to be working?:blush:


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## cheesehead (Mar 20, 2007)

cubdenno said:


> He drives a 4 door crew cab. There is just a tiny amount of space behind the rear seats. No way in hell to upfire. No room under seats for a box either if I recall.
> 
> Correct on both accounts.
> 
> ...


Well the front of the seats are leather but the rear of the seats (where the sub will be firing) is a nappy cloth(for lack of a better term!). 

I guess I continue on with my plan and see what happens.....


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## playedout (Feb 17, 2010)

ppl will be beggin to sit in the backseat to get a massage..lol


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## cheesehead (Mar 20, 2007)

playedout said:


> ppl will be beggin to sit in the backseat to get a massage..lol


I hope so. It will be a great way to not have to talk to the wife while driving!


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## softdome (Jan 25, 2008)

cheesehead said:


> Thanks for the reply!
> 
> Crew cab meaning 4 doors with the rear seat being a full seat. There is "some" room behind the seat but nothing under the seat. My plan was to build a wedge shaped box behind the seat. Between the cab wall and seat. I do not want to make any major modification to the truck. So no "blow through".:blush:
> 
> Back to the question........ will firing the sub into the seat be a problem?


 Cheezehead, I also have a crew cab. I think your plan to build a wedge is the best bet. I used that area to hole my amps and installed the sub & rears in the rear window (removed). First determine what size cabinet (cubic Ft.) will fit and select the drivers which will work in that volume. Unless you want the rediculous, destorted bass it not necessary to go with overly large drivers. sometimes multi smaller drivers will preform better. Used a sealed box for clean extended bass. Ported boxes are smoke and mirrors. Even a 8" woofer can get low enough with cabin gain to provide bass to Low E of a base guitar. I've done four 8's before and people couldn't believe how deep and fast they where. Oh by the way I only did two 10's in the rear window. I had the entire back camper cover if I wanted to be rediculous. The truck had the pass thru boot in it when I bought it or I would have never made it as complicated. Keep it simple. Good Luck Softdome 

P.S. firing into the back of the seat is not a problem as long as you provide suffient space for the sound to move into the cabin and for the excursion of the cone.


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## kkreit01 (Aug 27, 2009)

I'm in the same boat: Sport Trac with little room behind or under the seats. I've been firing into the seats, and it sounds fine. The seat backs are cloth. Just make sure to leave about an inch of space -- or however long your excursion is.


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## cubdenno (Nov 10, 2007)

softdome said:


> Cheezehead, I also have a crew cab. I think your plan to build a wedge is the best bet. I used that area to hole my amps and installed the sub & rears in the rear window (removed). First determine what size cabinet (cubic Ft.) will fit and select the drivers which will work in that volume. Unless you want the rediculous, destorted bass it not necessary to go with overly large drivers. sometimes multi smaller drivers will preform better. Used a sealed box for clean extended bass. Ported boxes are smoke and mirrors. Even a 8" woofer can get low enough with cabin gain to provide bass to Low E of a base guitar. I've done four 8's before and people couldn't believe how deep and fast they where. Oh by the way I only did two 10's in the rear window. I had the entire back camper cover if I wanted to be rediculous. The truck had the pass thru boot in it when I bought it or I would have never made it as complicated. Keep it simple. Good Luck Softdome
> 
> P.S. firing into the back of the seat is not a problem as long as you provide suffient space for the sound to move into the cabin and for the excursion of the cone.


Softdome, I gather that you have had less than satifying experiences with ported enclosures. All I can say is, you have had bad enclosures. A ported enclosure is no less "fast" than a sealed enclosure. hertz is hertz right? 40 hertz is 40 cycles a second in ported or sealed. The truth is ported enclosures are generally more efficient and can give a little more low frequency extension. The positive about sealed enclosures while generally less efficient and offering less low frequency extension, are wayyyy more forgiving than ported and usually smaller significantly. The benefit is really the vehicle. If there wasn't cabin gain sealed would be less popular except for enclosure size just due to roll off.


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## sqshoestring (Jun 19, 2007)

I've done a pile of trucks that way. Sometimes you can step the box or make the shape off so part of it contacts the seat, that way the sub can't get against it. I've also built the sides and face onto the body, though the cab back can be weak so maybe not a good idea with high power stuff. I did that with 8s in a ranger it worked fine but amp was only 2x50. Some of the seats are hollow and you can press the box right into them, though you have to make it so the sub is not of course. That is what I mean by stepped box where part of it pushes into the seat for more cf and the sub is elsewhere.


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## UngaroCD (Jan 11, 2010)

Just throwing my 2 cents in:

I've done several trucks with either a 4 6" sealed or 2 6" ported enclosure. Both sound really good. The ported sounds much better from the front as opposed to the back seat however.


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## cheesehead (Mar 20, 2007)

Thanks for all the replies!

I will be using the 12" BM MKIII which only needs .5 cuft of air space(sealed). The box I have figured out is about .43-.45 cuft. Which according to Nick at SI is acceptable. I could go slightly wider but then I wouldn't have sufficient space to mount my amps on the remainder of the back wall.

The fabric on the back of the seat does give some. I could possibly build the sides out 1/2"-1" more but then the rear seat would not latch. I'm not sure if this is a major deal or not. As mentioned in a previous post I will be using a grill from Madisound so the cone should never come in contact with the rear seat.


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## sqshoestring (Jun 19, 2007)

Inverted mount would be great there, but I can't figure how you would without making the box less volume.


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## cheesehead (Mar 20, 2007)

sqshoestring said:


> Inverted mount would be great there, but I can't figure how you would without making the box less volume.


I thought about that also. But like you mentioned I would lose volume not gain it.


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## baschwar (May 22, 2007)

kkreit01 said:


> I'm in the same boat: Sport Trac with little room behind or under the seats. I've been firing into the seats, and it sounds fine. The seat backs are cloth. Just make sure to leave about an inch of space -- or however long your excursion is.


I've done the same thing... I mounted two Elemental Design SQ10's in a box built by Sound Off Audio. They sound darn good even if they do slap the seat backs a bit... the box isn't cut at quite the right angle but it was good enough. If I were to do it again, I'd undermount the subs to give them a bit more room for excursion... :blush:


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