I'm building a box for a 12" Rockford Fosgate P212S4
The recommened volume for a sealed box is .85 cu ft. Sub displacement is about .049 cu ft.
So that would mean the box should be about .9 cu ft.
A box 15"x15"x10" with .75 thickness is about .9 cu ft.
Did I figure this out right? could someone please let me know.
Thanks
Replies (10)
uochronos on 12/20/2004 13:57:34
actualy when i add his up subtracting the driver volume nad the volume of the board i got around .89 for 15x15x10 may i ask how you got 1.08 victor? i dont think you subtracted all the wood properly perhaps or not the driver. all the wood though is around 700cubic inches which is around .4 cubic feet both my calculations and the program i was using gave me the same awnser withen like .05
unless both me and this program are way off i think the original 15x15 x 10 should work quite well if anything it may be a little on the small side but after subs actualy displacement this should be like .86-.89 should sound good.
if i'm wrong please let me know but i added up all the wood and then subtracted thats cubic footage from the box volume and then subtracted the volume of the woofer from the box volume. unless i'm forgetting something here.
Chronos
ttocs on 12/20/2004 14:04:42
I assume you mean those are the external dimensions for the box? Just want to be sure.
if that is the case then the internal dimensions would be 13.5" x 13.5" x 8.5" right?
13.5"/12(inches per foot) gives 1.125 feet
8.5"/12(inches per foot) gives .71 feet
Take 1.125 x 1.125 x .71 and I also get 1.05 cu feet of airspace in the box, prior to displacement.
sounds on 12/20/2004 16:07:38
what i posted was the external dimensions if that helps
uochronos on 12/20/2004 16:19:32
then in that case your internal dimensions well be about .89 which is withen tolerance if your aiming for .9... hope we have been of help
TTOCS 8.5/12 is .71 not .83 thats where your figures wheer off a bit i belive..
Chronos
ttocs on 12/20/2004 17:54:00
oooppssss...
dunno what yer talking about...
just kidding........
sounds on 12/21/2004 16:50:00
I was thinking of adding some polyfill so the bass won't sound so boomy would i need to change the dimension of the box to accommodate this?
swez on 12/21/2004 17:15:58
Nope, polyfil is more an absorbant material to catch some of the rear bass waves from the back side of the cone. It also has a srange, but uesful property that fools the sub into thinking (yeah, subs can't THINK) it is in a larger enclosure.
For a single 12" sub, 1 lb of polyfill is good. line the back, sides, top & bottom panels inside the enclosure. (~1.5" thickness) Use a stron staple gun to secure it.... 10mm staples are good.
Swez
cplkittle on 12/25/2004 18:22:04
Although it is great to aim for the exact airspace, on a sealed box, you have alot of room for error (+ or - .8 cubic ft.). It would be difficult to tell the difference between one that is .9 and one that is 1.0. Hope that relieves some stress.
sounds on 12/26/2004 22:23:02
got another question
how should the box be put together?
should the top and bottom be 15x10 and the sides should be 14.25"x 14.25" and 14.25"x9.25"? or is am I suppose to have the side ones 15x15 and 15x10 while the top and bottom 14.25x9.25?
I hope this makes sense, let me know if you need more explaination.
Thanks
uochronos on 12/27/2004 02:20:40
makes great since.. certain ways can be more stable and strong but in general unless you have a very power full sub thats isnt incredibley important... i have built boxes in both ways you listed and both have worked. i would sayput it together however is easiest... biggest thing is get some good glue.. standard wood glue well work but better ones such as gorrila glue and similar ones well give you alot of structural intgrity at the joints.
tested some differnt glues awhile back standard wood glue broke at the seem everytime when force was applied, gorrila glue and other simialar ones uauly break the wood before the joint when used properly.
Chronos
The recommened volume for a sealed box is .85 cu ft. Sub displacement is about .049 cu ft.
So that would mean the box should be about .9 cu ft.
A box 15"x15"x10" with .75 thickness is about .9 cu ft.
Did I figure this out right? could someone please let me know.
Thanks
Replies (10)
uochronos on 12/20/2004 13:57:34
actualy when i add his up subtracting the driver volume nad the volume of the board i got around .89 for 15x15x10 may i ask how you got 1.08 victor? i dont think you subtracted all the wood properly perhaps or not the driver. all the wood though is around 700cubic inches which is around .4 cubic feet both my calculations and the program i was using gave me the same awnser withen like .05
unless both me and this program are way off i think the original 15x15 x 10 should work quite well if anything it may be a little on the small side but after subs actualy displacement this should be like .86-.89 should sound good.
if i'm wrong please let me know but i added up all the wood and then subtracted thats cubic footage from the box volume and then subtracted the volume of the woofer from the box volume. unless i'm forgetting something here.
Chronos
ttocs on 12/20/2004 14:04:42
I assume you mean those are the external dimensions for the box? Just want to be sure.
if that is the case then the internal dimensions would be 13.5" x 13.5" x 8.5" right?
13.5"/12(inches per foot) gives 1.125 feet
8.5"/12(inches per foot) gives .71 feet
Take 1.125 x 1.125 x .71 and I also get 1.05 cu feet of airspace in the box, prior to displacement.
sounds on 12/20/2004 16:07:38
what i posted was the external dimensions if that helps
uochronos on 12/20/2004 16:19:32
then in that case your internal dimensions well be about .89 which is withen tolerance if your aiming for .9... hope we have been of help
TTOCS 8.5/12 is .71 not .83 thats where your figures wheer off a bit i belive..
Chronos
ttocs on 12/20/2004 17:54:00
oooppssss...
dunno what yer talking about...
just kidding........
sounds on 12/21/2004 16:50:00
I was thinking of adding some polyfill so the bass won't sound so boomy would i need to change the dimension of the box to accommodate this?
swez on 12/21/2004 17:15:58
Nope, polyfil is more an absorbant material to catch some of the rear bass waves from the back side of the cone. It also has a srange, but uesful property that fools the sub into thinking (yeah, subs can't THINK) it is in a larger enclosure.
For a single 12" sub, 1 lb of polyfill is good. line the back, sides, top & bottom panels inside the enclosure. (~1.5" thickness) Use a stron staple gun to secure it.... 10mm staples are good.
Swez
cplkittle on 12/25/2004 18:22:04
Although it is great to aim for the exact airspace, on a sealed box, you have alot of room for error (+ or - .8 cubic ft.). It would be difficult to tell the difference between one that is .9 and one that is 1.0. Hope that relieves some stress.
sounds on 12/26/2004 22:23:02
got another question
how should the box be put together?
should the top and bottom be 15x10 and the sides should be 14.25"x 14.25" and 14.25"x9.25"? or is am I suppose to have the side ones 15x15 and 15x10 while the top and bottom 14.25x9.25?
I hope this makes sense, let me know if you need more explaination.
Thanks
uochronos on 12/27/2004 02:20:40
makes great since.. certain ways can be more stable and strong but in general unless you have a very power full sub thats isnt incredibley important... i have built boxes in both ways you listed and both have worked. i would sayput it together however is easiest... biggest thing is get some good glue.. standard wood glue well work but better ones such as gorrila glue and similar ones well give you alot of structural intgrity at the joints.
tested some differnt glues awhile back standard wood glue broke at the seem everytime when force was applied, gorrila glue and other simialar ones uauly break the wood before the joint when used properly.
Chronos
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