# Downfiring setups - why?



## Mless5 (Aug 21, 2006)

I am curious as to why people do downfiring enclosures? Do they sound better vs "regular"?


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## brownmoses (Jul 23, 2008)

i just assumed it was another option to get your setup to sound good to you. i bet there are plenty of cars where firing up might sound better.


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## jonny987 (Aug 16, 2008)

some info here:
http://www.diymobileaudio.com/forum/showthread.php?t=32155


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## 60ndown (Feb 8, 2007)

up sideways, down, should all sound the same if designed and tuned correctly.


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## lowpoke (Jun 1, 2008)

I plan to build quite a shallow sub enclosure because I have a convertible top encroaching on a good deal my trunk space. By downfiring I can make the enclosure shallower than the depth of the driver.


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## chithead (Mar 19, 2008)

In my 2003 regular cab Ram I built a downfiring sealed "wedge" box that was the best solution for my application. I tried a few other designs, but the downfiring yielded the best results in the limited space.


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## aztec1 (Jun 13, 2008)

I always thought it would provide a loading surface, especially for the lowest frequencies. I've built a couple that actually hid some noise...maybe some of it was masked by firing into the floor?


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## Hispls (Mar 12, 2008)

aztec1 said:


> I always thought it would provide a loading surface, especially for the lowest frequencies. I've built a couple that actually hid some noise...maybe some of it was masked by firing into the floor?


This is consistant with my experience as well. 

Usually I find the loading effect is about the same as firing to the rear with woofers close to the back of the car. It's also a good option for stealth, and you are much less likely to dammage the cones from something bumping into them.

Worth testing anyway, and in some installs it is very practical and offers some good advantages.


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## jdc753 (Nov 14, 2007)

I think as others have said much of it is install and overall aesthetic design that brings out the use of a downfiring enclosure. For me I am replacing or build a center console area in my truck since its pretty much the only place for the sub(s) to fit. Upfiring would just be a pain since its a console and I would like to rest my arm or drink or something on it. I could fire them back but this will remove floor loading plus be an easy way for someone in the back row to accidentally kick the sub, and is really only good for a single sub application instead of trying to fit 2. 

I noticed an increase in loudness when going from upfiring to downfiring in my truck but also noticed a slight variation in sound. I think this was due to finding some new rattles in the floor or just a small coloration of the sound coming from the reflections and loading.


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## Mless5 (Aug 21, 2006)

Ok, will placing a box upside down on (2) 2x4s for testing purposes be sufficient or is there more to it?


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## bobduch (Jul 22, 2005)

For me the biggest reason to downfire in a car is protection. I don't have to worry about what someone else might do near my woofer or what they put or spill in my vehicle. Cone sag can be a concern, although my 20 year old Velodyne ULD 18 in my house (downfiring) is fine. And how many people on this forum are going to have the same driver for more than a few years anyway? (besides me).
Disclosure:
In my van the sub is in the console firing at a 45 degree angle down and front.
In my car I plan on firing up from rear deck.


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## 60ndown (Feb 8, 2007)

Mless5 said:


> Ok, will placing a box upside down on (2) 2x4s for testing purposes


yes just flip the thing and experiment


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## RajunCajun (Jul 27, 2008)

60ndown said:


> up sideways, down, should all sound the same if designed and tuned correctly.


Im with 60 on this one, if done correctly the only thing that sould affect the sound is the invidual acoustics of the vechile.


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## TXwrxWagon (Sep 26, 2008)

the old-school of thought/training in car audio, especially in small cabins (trucks, convertibles, small hatches etc) was trying to get as much of the initial 1/4 wave of the subwoofer inside the vehicle & arriving @ the listeners ear. Just like rear firing in an average size hatchback (Mustang, Eclipse, etc) get as much of the wave in the car... 

A down firing enclosure will add to that the barrier loading, as mentioned by others. The rule I was taught years ago on barrier loading is 1/2 the radius of the woofer. So a 10" woofer would be loaded 2.5" above the surface. Using the +5% of xmax or 1"-3" + xmax, 99% of the time will be just that 1/2 the radius... its just a safer/easier rule that has always worked for me.

If you look @ JL Audio's Stealth boxes, a good portion are downfiring consoles (almost ALL their truck boxes are. Many of their hatch boxes are also corner/downfiring/barrier loaded for additional gain.

I usually look at every project to see if there is a viable downfiring or brrier loaded config available.

With th advent of T/A & so many circuits & processors, unusual box designs have kinda lost popularity.

Protection & stealth are additional benefits, as already said.

Rob


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## JayinMI (Oct 18, 2008)

While, in theory, they should sound about the same, the loading and filtering effects of downfiring boxes seem to work better in certain vehicles. 

The main places I find downfiring to work best are trucks where space is at a premium, and convertibles. 

In every convertible I've ever done, if the woofers were firing up, generally when the top is down we lose nearly all output. 

That's the main reason I use downfiring boxes. The protection aspect is a bonus. 

Jay


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## quality_sound (Dec 25, 2005)

bobduch said:


> Cone sag can be a concern,


It is no more of a concern than upfiring.


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## lowpoke (Jun 1, 2008)

lowpoke said:


> I plan to build quite a shallow sub enclosure because I have a convertible top encroaching on a good deal my trunk space. By downfiring I can make the enclosure shallower than the depth of the driver.



Sorry guys, I misunderstood. I just assumed the discussion was about inverting the driver to fire into the enclosure, not just flipping the enclosure upside down!


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## sobe_death (Jul 31, 2008)

JayinMI said:


> While, in theory, they should sound about the same, the loading and filtering effects of downfiring boxes seem to work better in certain vehicles.
> 
> The main places I find downfiring to work best are trucks where space is at a premium, and convertibles.
> 
> ...


Jay, are you talking about all convertibles? 2 seaters, 4 seaters, hardtops? 

Reason I ask is because I have a perfect little storage well that would hold an upwards firing woofer in my convertible. In fact, that's how most people put them in these cars...

Paneling in...








Paneling out...


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## JayinMI (Oct 18, 2008)

Well, you do the best with what you got. 
That well is certainly a nice place, but in most cases that I have dealt with, you lose almost all the bass when the top is down. I generally use a downfiring box in the passenger compartment when I can. 

I did have one exception, tho. I did a Pioneer 12" flat woofer firing up from in the trunk in a 4 seat 2 door benz convertible. Even with the top down it still had impact. It's the only car I remember that performed that way...of the MANY convertibles I've done, that's the only one that comes to mind. Other than that I try to down fire them in the passenger compartment.

What kind of car is that? S2k? Miata? 

Jay


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## elvisjer (May 13, 2008)

Be careful with a downfiring install though. Some subs have too little gap between the surround of the speaker and the mounting area to be able to safely operate unless you cut a circle PERFECTLY for the sub. I inversely mounted my Brahma MKI and ended up damaging the surround because there simply isn't a wide enough mounting area around unless you precision engineer a hole, which i couldnt do. For my AW-8240 i have it inversely mounted for space reasons but also you can get away with a little smaller box since the recommendations on box sizes are assuming the woofer is taking up X amount of airspace. Right now my sub is in a inverse mount in a custom ported box and it sounds better than it ever has. Also, i can't get enough of the look of this sub's rear end


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## 60ndown (Feb 8, 2007)

sobe_death said:


> Jay, are you talking about all convertibles? 2 seaters, 4 seaters, hardtops?
> 
> Reason I ask is because I have a perfect little storage well that would hold an upwards firing woofer in my convertible. In fact, that's how most people put them in these cars...
> 
> ...


weird, when you remove paneling the car changes color?


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## quality_sound (Dec 25, 2005)

elvisjer said:


> Be careful with a downfiring install though. Some subs have too little gap between the surround of the speaker and the mounting area to be able to safely operate unless you cut a circle PERFECTLY for the sub. I inversely mounted my Brahma MKI and ended up damaging the surround because there simply isn't a wide enough mounting area around unless you precision engineer a hole, which i couldnt do. For my AW-8240 i have it inversely mounted for space reasons but also you can get away with a little smaller box since the recommendations on box sizes are assuming the woofer is taking up X amount of airspace. Right now my sub is in a inverse mount in a custom ported box and it sounds better than it ever has. Also, i can't get enough of the look of this sub's rear end



Just because it's downfiring doesn't mean you have to mount the sub inside the box.


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## Turborusty (Aug 7, 2007)

I downfired mine for safety, so my kids won't punch or jump on them...plus, being in the rear of my daily driver SUV........it gave me a platform to still set groceries and luggage on.

It may help out with wavelength since it fires out the rear, so the sound vave travels back, up, and then forward....but who knows? It certainly sounds better facing down than it does up. But it's more complicated than just propping up a regular box, as mine is enclosed on 3 sides....all the sound comes out a single area, to the rear of the enclosure.

I remember someone saying something about there being a formula for the distance the baffle should be from the floor...something like 2.5" or something...by luck, mine's exactly that.




























































Turborusty


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## sobe_death (Jul 31, 2008)

sobe_death said:


> Jay, are you talking about all convertibles? 2 seaters, 4 seaters, hardtops?
> 
> Reason I ask is because I have a perfect little storage well that would hold an upwards firing woofer in my convertible. In fact, that's how most people put them in these cars...
> 
> ...


It's an S2k. I'm wondering if a downward firing setup would be feasible in an arrangement like that. The other option is a fiberglass box in one corner of the trunk...


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## UCF52 (Nov 20, 2007)

sobe_death said:


> It's an S2k. I'm wondering if a downward firing setup would be feasible in an arrangement like that. The other option is a fiberglass box in one corner of the trunk...


I actually saw a nice enclosure built in the passenger side foot well of an s2k that housed and 8 (maybe a 10). If I had a 'vert that's what I would do (especially with deep foot wells). Search around s2ki for it - that's where I saw the build.


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## sobe_death (Jul 31, 2008)

Yeah, I know that guy from when I lived in Atlanta. He actually ended up cutting the metal in the footwell to get enough space to mount the 10" in there, which is a BIG no-no in my car. If I can somehow get .5 cubic feet up there then I will have a 9Kv2 down there ported...


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## speakerboy (Oct 2, 2007)

Doesn't loading the woofer by making it fire down effectively change the tuning frequency? By pointing it towards the floor, you are almost trapping a cushion of air between the sub and the floor, and then the sub has to try to compress it. My brain says it would raise the tuning frequency.


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## smgreen20 (Oct 13, 2006)

I've done a huge array of boxes for my truck and down fire was the worst. I couldn't tell any real difference in the sound, but it shook the piss out of my truck to where more rattles were noticable and although the sound was good, it lacked impact. I believe it was due to the shaking of the truck floor and the rattles just playing tricks on my mind. 

That's just my opinion and for my type of vehicle only. 2000 GMC Sierra Ext cab.

A friend of mine did an install in a Jeep Wrangler w/a single 12" down fire that sounded pretty sweet.

I did an install for a friend that has a Ford Expadition w/a single 12" RE SE down fire in the back that souded pretty tight as well.

In conclusion, it mostly comes down to what type of vehicle you have and where/how you mount things.


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