hi guys, haven't posted for a while, but i finally have a question. i have a 1984 landcruiser wagon, and i want to build a false floor in the back with the rear seat folded forwards and flat, sort of like a panelvan setup. I'm doing this so i can leave my bed setup in the back! anywaay, at the moment i have 2 12"s in a box just free floating, and the idea is to build a new box into the floor. since this is my primary concern, the box determines the height and the room left over for the rest of the floor, where i may put large drawers which can be pulled out when the tailgate is dropped.
What i want to know is what my best way of facing the subs is (they've always soundest best facing the back, but this won't be possible now), and what the best sort of box would be now that they will usually be hidden under the mattress, and probablt facing up if in a sealed box. any ideas would be great!
Replies (6)
Swez on 09/30/2003 08:55:26
In very general terms, most sealed 12's need about 1.0-1.25 cf of airspace per sub. You have plenty of width behind the seats so a false floor application makes sense, with the subs mounted in a face up position.
Most 12" subs need 8-10" of chamber "depth" to vent/cool properly. You can make up the rest of the air space by the other 2 parameters. We can say 14" is adequate for baffle panel to mount each sub, so the only calculation left is how long (width) the chamber will need to be for these subs.
Tell us more about the sub model and brand you have now. A Weblink with specs would be most helpful here.
Finally, you can still get the subs to fire to the rear by building a removable scoop type cover over the subs. This scoop will direct the bass waves back to the rear of the vehicle and you will not lose that bass performance until the scoop is removed or you have to cover the subs with your sleeping gear.
Comments?
Swez
bairsjw on 10/2/2003 07:47:38
that's pretty much what i wanted to know thanks! i'm not sure what you meant by the scoop though, you mean like say a bonnet scoop, except it works backwards?
the only other thought was a bandpass, i wasn't sure if that would make the base sound like it came from everywhere, and wouldn't matter which way the subs faced. depth is probably the limiting factor there though.
here's a weblink for the subs, they're running off an alpine V12 MRD M-500 http://www.alpine.com.au/active_pages/amplifier_page.asp
heres the subs (x2), i think, mine are ws304c but i bought it in australia, so maybe you have a different model in the us.
http://www.pioneerelectronics.com/pe/product/detail/0,,2076_4059_2128095,00.html
I know they need about 1 cu. ft of space, but it is ok to be fairly shallow, like 8 inches from the top of the box to the bottom right? or was what you said 8 inches from the back of the sub to the back of the box?
thanks for your help swez, and sorry about the extra post
bairsjw on 10/2/2003 08:52:28
actually mine aren't ws304c's they are TS-W304C's and here's the right page
http://www.pioneerelectronics.com/pe/product/detail/0,,2076_4059_34337,00.html
Swez on 10/2/2003 08:54:06
Hummmm, the subs you show in the link are "free air" version and generally, do not use an enclosure. They are just mounted to a baffle panel and no box. The air space behind the woofer baffle panel is your enclosure and a poor one at that for deep, low distortion bass.
The specs noted do recommend that a 1.2 cf enclosure (sealed) per sub is OK. So these should work.
As for a scoop (bonnet) yes, you seem to have the idea. Will look a bit like this : (_____ The subs are mounted facing upward and the scoop (bonnet) will deflect the bass waves to the rear and propagate throughout the vehicle well as bass waves are omni-directional. This will work nice in your application, if you don't get the bass sound right from upward firing subs.
See the picture? The bonnet can be removed as needed for cargo and added space if you like. It just needs to be made of a flexible yet well reinforced to prevent resonances from the scoop.
Swez
bairsjw on 10/4/2003 00:08:08
I'm pretty sure the first link, TS-W304F's are different to mine, as mine definately aren't free to air subs, must just look similar. thanks for all the help, I'll see how i go!
Swez on 10/4/2003 09:32:01
OK, looking at the new link, same deal... 1.2 cf/sub (sealed) and these are not Free Air design.
Now, the trick is to design an enclosure that meets your sonic and space needs. Come back if you need more help.
Swez
What i want to know is what my best way of facing the subs is (they've always soundest best facing the back, but this won't be possible now), and what the best sort of box would be now that they will usually be hidden under the mattress, and probablt facing up if in a sealed box. any ideas would be great!
Replies (6)
Swez on 09/30/2003 08:55:26
In very general terms, most sealed 12's need about 1.0-1.25 cf of airspace per sub. You have plenty of width behind the seats so a false floor application makes sense, with the subs mounted in a face up position.
Most 12" subs need 8-10" of chamber "depth" to vent/cool properly. You can make up the rest of the air space by the other 2 parameters. We can say 14" is adequate for baffle panel to mount each sub, so the only calculation left is how long (width) the chamber will need to be for these subs.
Tell us more about the sub model and brand you have now. A Weblink with specs would be most helpful here.
Finally, you can still get the subs to fire to the rear by building a removable scoop type cover over the subs. This scoop will direct the bass waves back to the rear of the vehicle and you will not lose that bass performance until the scoop is removed or you have to cover the subs with your sleeping gear.
Comments?
Swez
bairsjw on 10/2/2003 07:47:38
that's pretty much what i wanted to know thanks! i'm not sure what you meant by the scoop though, you mean like say a bonnet scoop, except it works backwards?
the only other thought was a bandpass, i wasn't sure if that would make the base sound like it came from everywhere, and wouldn't matter which way the subs faced. depth is probably the limiting factor there though.
here's a weblink for the subs, they're running off an alpine V12 MRD M-500 http://www.alpine.com.au/active_pages/amplifier_page.asp
heres the subs (x2), i think, mine are ws304c but i bought it in australia, so maybe you have a different model in the us.
http://www.pioneerelectronics.com/pe/product/detail/0,,2076_4059_2128095,00.html
I know they need about 1 cu. ft of space, but it is ok to be fairly shallow, like 8 inches from the top of the box to the bottom right? or was what you said 8 inches from the back of the sub to the back of the box?
thanks for your help swez, and sorry about the extra post
bairsjw on 10/2/2003 08:52:28
actually mine aren't ws304c's they are TS-W304C's and here's the right page
http://www.pioneerelectronics.com/pe/product/detail/0,,2076_4059_34337,00.html
Swez on 10/2/2003 08:54:06
Hummmm, the subs you show in the link are "free air" version and generally, do not use an enclosure. They are just mounted to a baffle panel and no box. The air space behind the woofer baffle panel is your enclosure and a poor one at that for deep, low distortion bass.
The specs noted do recommend that a 1.2 cf enclosure (sealed) per sub is OK. So these should work.
As for a scoop (bonnet) yes, you seem to have the idea. Will look a bit like this : (_____ The subs are mounted facing upward and the scoop (bonnet) will deflect the bass waves to the rear and propagate throughout the vehicle well as bass waves are omni-directional. This will work nice in your application, if you don't get the bass sound right from upward firing subs.
See the picture? The bonnet can be removed as needed for cargo and added space if you like. It just needs to be made of a flexible yet well reinforced to prevent resonances from the scoop.
Swez
bairsjw on 10/4/2003 00:08:08
I'm pretty sure the first link, TS-W304F's are different to mine, as mine definately aren't free to air subs, must just look similar. thanks for all the help, I'll see how i go!
Swez on 10/4/2003 09:32:01
OK, looking at the new link, same deal... 1.2 cf/sub (sealed) and these are not Free Air design.
Now, the trick is to design an enclosure that meets your sonic and space needs. Come back if you need more help.
Swez
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