Proper subwoofer placement

[Rand McNally]

I have been thinking of building a "fake floor" for the cargo area of my 2001 XJ. No one will even know I have a stereo system installed. I would like to mount my amps/caps/cd changer all under the "fake floor". I was wondering if it would work to have a downward firing sub? How far off the floor would the sub need to be? How much room would I need to allow the soundwave to escape the under floor? I tried searching here and on the web and there isn't any information about downward firing subs. Must not be the way to go or others would be talking about it... Thanks for your help!

 

[MDMIKE]

From what I understand (don't take it as gospel), but a down-firing subwoofer has to be half the diameter of the sub, spaced off the floor. So, if you have a 12" sub, build your false floor 6" off the floor and vent it out the front or the back. Someone correct me if I'm wrong, its been a long time since I've dealt with "subwoofer tech"

MIke

 

[BIG-G]

well its NOT 6" but u will have quite a high floor for it 2 work. Put ur sub in the "cubby hole"! U can build a good stealth box that fits a good 10" sub there! Theres a thread on it, do a search.

 

[sbxoxj]

build a bandpass box

 

[Rand McNally]

I have looked at the threads on the "cubby hole" box. I just thought it would be nice to have it completely hidden. Plus I read somewhere that subs work best when fired towards solid objects. The floor is pretty solid.

A bandpass box is totally out of the question. They seem to be really big and I don't want to give up any cargo space. There isn't much to begin with.

Thanks for the help everyone. I will keep hunting...

 

[boise49ers]

Rand I bet you never get lost do you ? Any way I have a bandpass in mine and yes they take up alot of room. I just take it out if I need the room. It is usually just when I go hunting, camping, or wheelin. My system still sounds good even when the sub is out.I don't listen to it when Hunting or Wheelin though. 6x9 Infinitys pump out quite a bit of bass themselves. My son is going with the Cubby hole sub. At least that is the plan after cutting up the plastic cubby piece.

 

[Ron4x4]

your fake floor will work fine it will just have to be tall enough (at least where the subis mounted) to have the Sub 2-3 inches off the floor and for an inch more than the mounting depth. If I were to do this I'd build a Step up behind the back seat and then slope it down toward the back door.
Build it out of cardboard first and see if you like it. Then build your box out of wood.

 

[Rand McNally]

I found this downfiring sub box on Crutchfield's website.
http://www.crutchfield.com/S-sNttOhmxHcy/cgi-bin/Prodview.asp?readmore=true&i=044UHC112#Tab
Now keep in mind I do not want a box that is this high, but if you look at how far it is sitting off the floor you will notice it isn't that far. Maybe an inch or two. The box then would only need to be high enough to give clearance for the sub, which is 4.875" according to the tech sheet (http://www.jlaudio.com/subwoofers/pdfs/10_12W6_MAN.pdf). So add a couple of inches to make room for everything, the "floor" should only be about 8" high. Make sense?

 

[Ron4x4]

I found this downfiring sub box on Crutchfield's website.
http://www.crutchfield.com/S-sNttOhmxHcy/cgi-bin/Prodview.asp?readmore=true&i=044UHC112#Tab
Now keep in mind I do not want a box that is this high, but if you look at how far it is sitting off the floor you will notice it isn't that far. Maybe an inch or two. The box then would only need to be high enough to give clearance for the sub, which is 4.875" according to the tech sheet (http://www.jlaudio.com/subwoofers/pdfs/10_12W6_MAN.pdf). So add a couple of inches to make room for everything, the "floor" should only be about 8" high. Make sense?

2.5+4.875+1+.75 = 9.03 inches usng 3/4 MDF. $199 is a bit steep for a box like that. For my stuff I'd charge about $150 Total including shipping.

 

[Rand McNally]

2.5+4.875+1+.75 = 9.03 inches usng 3/4 MDF. $199 is a bit steep for a box like that. For my stuff I'd charge about $150 Total including shipping.

What are those measurements?

I agree, $200 + shipping for a sub box? That is crazy. That is why I am building my own. I have done it before with conventional boxes, but never anything like this. Should be interesting...