Theory behind downfiring box?

[dropkick13 10+ year member]

Could someone explain the theory behind it? Basically I would think that the sub would sound like butt from it pushing air directly into the carpet....thus muffling the sound AND redirecting the air back to the sub and causing the sub to lose clarity.

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[Immacomputer 10+ year member]

So then by your assessment, sealed enclosures should sound horrible as all they do is push air directly into wood and then redirecting air back to the sub causing the sub to lose clarity. I guess if you put carpeting in a sealed enclosure that the sound would become muffled.

 

[PV Audio 5,000+ posts]

There are really only two reasons to downfire: aesthetics, or bass enhancement. Most often, it is done because people don't want to see or think that there's a subwoofer in the room, and having the cone face out into the room makes it very obvious what it is. However, the other reason you down fire is because you can load the output off of the floor which actually makes the output greater. This only works well on hard surfaces though, but it still works nonetheless.

 

[daniel.lindsey 10+ year member]

i think what he means is like when u have a box under a seat in the back of a truck or something, where its close to the ground and practically hitting the carpet? not sure if thats what he means though

 

[squeak12 10+ year member]

In trucks, the often downfire so they arent right against the seat. The subs arent actually touching the ground either, theres space there so they wont hit the ground, get kicked, etc.

 

[luvinthebass 5,000+ posts]

what if you had a box with a sub that was ported and u faced the port on the ground would the bass be deeper or louder or be muffled?

 

[maldecido33 10+ year member]

it would screw up the tuning by making the port "think" its longer than it really is

 

[dropkick13 10+ year member]

i think what he means is like when u have a box under a seat in the back of a truck or something, where its close to the ground and practically hitting the carpet? not sure if thats what he means though

This is exactly what I meant actually. I have an ext cab silverado and I'm building a box right now to go under the seat. The downfiring box is extremely common, but the typical build only leaves 1''-2'' of clearance between the sub/s' surround and the carpet. I am no acoustical expert, but I just would have thought this would make the sub sound like butt. People with these boxes do not complain though so I'm just looking for a little bit of a scientific explanation between the theory of a downfiring box and an upfiring box. I can't decide which to build.

and how does a downfiring box increase output?

 

[tcguy85 10+ year member]

and how does a downfiring box increase output?

well for HT it is usually a really good option. the sound hits the floor and it reflected throughout the room. not sure how well this works in a car though. i have never tried it or seen it.

 

[Immacomputer 10+ year member]

It's more about the sub being able to load off of something that is beneficial. It will work the same in a car as it does in a house. As long as the driver has something that resists movement and applies pressure back on the cone, there will be an increase in output. Just like corner loading the sub in a room.

 

[PV Audio 5,000+ posts]

Bingo.

And //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif at your sig image.

 

[AVX Mike 10+ year member]

You also have to leave 1/4 to 1/3 of the cones diameter for clearance other wise you will run into cancellation issues. I have recently built a center console for a F-350 with 4-8" Focal Utopia BE subs firing down with slot ports firing forward into the dash. Amazing sound!! Between loading the subs to the front and the ports, it sounds like the subs are in the dash.

 

[dropkick13 10+ year member]

I got an RL-p12. If all I have is 1.5" for clearance between the sub and carpet, should I just upfire instead?

 

[AVX Mike 10+ year member]

Yes, with a 12" sub you would need 3-4" of clearance between the sub and the floor.

 

[goodstuff 10+ year member]

A friend of mine had 3 12's in a downfiring box at one point. It made my eyeballs wiggle it hit so hard.