# Thoughts on firing position in a suv



## cheesehead (Mar 20, 2007)

I just came a crossed a few posts in the install section where posters have mentioned that down firing subs in a suv my be optimum.



Thumper26 said:


> downfiring i believe is one of the more optimum ways of running subs in suv's. something about the sub firing very close to the floor causes it to have higher output.
> 
> i don't understand it enough to fully explain it, but it's worth a try.





kingstretch said:


> haha - funny you said it that way. I was thinking the same thing judging by other posts I've read, but I don't really understand the technical aspect of it so I didn't want to sound stupid trying to repeat it. Suffice it to say that from what I've read - downfiring is a pretty good setup. Everybody has their own opinion though.


Any thoughts on this? 

I am in the design process right now. I am looking to build a 1.25 cu.ft. enclosure for a 12" AA Atlas. I was planning on rear firing towards the hatch until I stumbled a crossed this. Any thoughts or insights would be appreciated!


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## 89grand (Nov 23, 2006)

Well one for sure advantage is you wouldn't need grilles or have to worry about protecting the subs at all. I see no reason why you wouldn't get good output.


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## bobditts (Jul 19, 2006)

Ive always enjoyed downfiring enclosurse in smaller cab vehicles like trucks and under the front seats of cars. Ive never heard a down firing in a SUV. Most people aim towards the back of the vehicle and up a little bit for the longest wavelength.


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## Turborusty (Aug 7, 2007)

I've tried positioning boxes in every possible direction and down-firing in my Durango is by far the best sounding.....so I built my new box to fire down and out the rear. Definitely a big gain in output!

The protection is great.....before I built this one, I had a 15" firing up and one day my 3 year old hopped the back seat and I found him sitting in the middle of the cone.  I can also stack groceries and stuff on it. Perhaps I'll build trays on top to keep stuff in place.

Yes, I still need to carpet it, but that's on the back burner right now.

It's not fancy but it kicks ass!




















































Turborusty


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## t3sn4f2 (Jan 3, 2007)

Isn't this type of install called slot loading? Would it be even better to add a braced face in front of the subs so that it isolates the waves from vibrating the floor and causing rattles?


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## Turborusty (Aug 7, 2007)

I hear no rattles.........but yes, that would likely be best.

But then again, there is a science to slot-porting and I didn't follow it. I just needed the box to be as low-profile as possible. Adding another .75" of height didn't appeal to me. Not to mention, if I need to drop a sub outta the box for whatever reason, I don't want to disassemble the enclosure to do it.


Turborusty


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## cheesehead (Mar 20, 2007)

Thanks for the info and pic.s turborusty. 

I really like the idea of protecting the sub by down firing.

I'll have to do some research on this.


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## Turborusty (Aug 7, 2007)

cheesehead said:


> Thanks for the info and pic.s turborusty.
> 
> I really like the idea of protecting the sub by down firing.
> 
> I'll have to do some research on this.


No sweat......There are no readily available grilles to fit my subs anyhow, so this really worked out on all fronts for me.

It is also a good theft deterrent. When I get it carpeted, you won't be able to tell anything's there through the tinted glass.


I built my box to be as shallow as possible, then left a 2" gap underneath.....and as you can see, it has 3 walls so the only opening for sound to escape is in the rear. Looking at it now, I could have gone with less gap, since the subs don't have a huge xmax and are recessed .75 inches as it is..


Turborusty


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## stoeszilla (Jul 9, 2007)

The Decware site has a sub box that incorporates this idea of bottom firing drivers.

http://www.decware.com/newsite/invertedwedge.htm

Quoted from the site:

"SIZE: 32" wide x 12.75" tall x 14" deep

The Inverted Wedge Design was done for 10 and 12 inch drivers as a sound quality and SPL box. Originally done with cars in mind we have found it to also work well in the home as an audiophile quality subwoofer. This particular design was one of our most popular around the time we did the Deathbox. It was featured in our 1991 Decware box catalog and could be found in many serious competition cars during those early IASCA days.

It has 3 main features that set it apart from other box designs around the same size:

1) It pre-loads the drivers against the floor of the vehicle / increasing damping and power handling.

2) It couples more bass to the interior cabin space then any other box design of the same size.

3) It has 8 times the physical coupling to the vehicle with over 1 lb per square inch verses the normal 0.13 lb per square inch of a normal box.

What all this means is tight, deep, loud non-fatiguing bass. In hatchbacks or larger trunks it simply kicks ass. It's a classic lesson in how the right box design can give you up to 4 times more bass from the same pair of woofers. Your amp will run cooler, clip less, draw less current from your charging system, have more headroom and lower distortion as a result.

Designed for woofers that are used in sealed boxes between 1/2 and 3 cubic feet. We always ran a pair of 8 ohm woofers in parallel for a 4 ohm load. (Remember bridging a stereo car amplifier makes the amplifier see only 1/2 the actual speaker load so this example creates a 2 ohm load for the amp)."

They recommend a 2" opening to allow the driver to "breathe"...seems you got that dimension right-on Turborusty.


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## ocuriel (Oct 7, 2005)

Nice build turborusty.


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## jazz391 (May 17, 2007)

how does this work for ported enclosures?


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## cheesehead (Mar 20, 2007)

stoeszilla said:


> The Decware site has a sub box that incorporates this idea of bottom firing drivers.
> 
> http://www.decware.com/newsite/invertedwedge.htm
> 
> ...


Nice Find!  

Thanks for the info guys!

I think I just figured out my next box design!  

I'll try to remember to take some pic.s of the build to post.


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## Turborusty (Aug 7, 2007)

Thanks for the props guys......it was really a shot in the dark for me. I knew I needed a down-firing box for utility and protection reasons. 

I used 2" to make sure I wouldn't be slapping the floor at full extension, though I'll need more power for that. I am running those subs with the mono channel of a 3-channel amp, it's putting out 250RMS @ 2ohms.....not earth-shattering by any means, but I have to keep my sub level at around -1 to -3 in order to not overpower my front stage that's running 150RMS per channel.

It's tight, clean, and a lot louder than you'd expect for a pair of inexpensive 10's with a low to moderate amount of power.

After my son butt-bombed the 15, I decided I had to change the setup so I tipped the box upside down and screwed some feet on that I cut from scraps of 2x4, to elevate the woofer for clearance.........it made a huge difference in output, so that's how I knew what I needed to build for my 10's.



Turborusty


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