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View Full Version : really quick question!!!Please help



zaid990
05-18-2009, 01:28 AM
Hey everyone i just bought 2 Rockford fostgates P1S412 12's, and i was thinking i was gonna get a vented box but i just came across a guide that said
Sealed box (and sealed bandpass) woofers should have the following characteristics:

* Qts => 0.40
* Fs <= 35 Hz
* Xmax => 4 mm

and the subs have the same characteristics, so should i go with a sealed enclosure?? also the specs of the sub say that for a sealed encloser i should have cubic space of .6-1.8 so where should i go on that scale??? and also would a prefab box make a diffrence if it is sealed ( i know prefab is bad with vented) thanks for everything

alvitae
05-18-2009, 01:32 AM
Enclosure Compatibility


Recommended Sealed Box Volume: The sealed box sizes recommended by Rockford Fosgate range from 0.70 cu/ft to 1.80 cu/ft. Within this range, the ideal size recommended by Rockford Fosgate is 1.02 cu/ft, so this is the enclosure recommended by Crutchfield.

Recommended Vented Box Volume: The vented box size recommended by Rockford Fosgate is 1.79 cu/ft, so this is the enclosure recommended by Crutchfield. One 3" diameter x 6" long port should be used with the 1.79 cu/ft enclosure. Found that doing a bit of research. Don't know if it helps or not. And they recommend tuning to 36 hz

zaid990
05-18-2009, 01:34 AM
so could i just buy a prefab sealed box and than make a port on it???

Louisiana_CRX
05-18-2009, 01:37 AM
so could i just buy a prefab sealed box and than make a port on it???

that could work

marcotheclepto
05-18-2009, 01:40 AM
so could i just buy a prefab sealed box and than make a port on it???

do your math right and make sure its sealed well should be okay....

zaid990
05-18-2009, 11:26 AM
ok so how would i go aboutt making a port would i just make one the size that alvitae said (One 3" diameter x 6" long port should) and drill the box and put in the port?? and how would i tune it if i put the port tube into it??

Oh and what do you mean do the math right ( volume, tuning etc.)??

thanks for all the help

and also i found this box (http://www.bestbuy.com/site/olspage.jsp?skuId=9026984&type=product&id=1218009781817) but it looks like the space inside is a bit small, so if i used a port 3"x6" on this box would it tune to the right frequency, and i checked rockford's site and it says that if i ported a box i should tune it to 36 hz

thanks

dappa5
05-18-2009, 01:31 PM
you need to use aeros easiest way to tune a prefab
http://www.thrilleraudio.com/detail.aspx?ID=42
there are other options but this should fit your skill level

dappa5
05-18-2009, 01:35 PM
oh yeah www.psp-inc.com look 4 port length calc
gl

zaid990
05-18-2009, 06:33 PM
ok so do you guys think i should get this box (http://www.bestbuy.com/site/olspage.jsp?skuId=9026751&type=product&id=1218009779475) and seal the front vent and make my own ports ( because that is close to the size the box needs to be) sub specs say for vented i need 1.79, or could i get this box (http://www.bestbuy.com/site/olspage.jsp?skuId=9026984&type=product&id=1218009781817) and port is ( is there anyway i can make the subs think its bigger? polyfil?) and if so how would i go about doing that?? or any other ideas

dappa5
05-18-2009, 06:52 PM
i say build your own box will be cheaper and the experience will be helpfull later
1 sheet mdf=$25 or so you could get 2 + of those boxes out of one sheet

zaid990
05-18-2009, 07:13 PM
ok, so if i make my own box, the only things im unsure about are the circle cutouts( for subwoofer) i dont have a router, and bracing, i was thinking about making a box like this (http://www.bestbuy.com/site/olspage.jsp?skuId=9026984&type=product&id=1218009781817) but to my own specs, and porting it. so how would i cout out the circles, and do i need to brace it? and if so how would i do that and how much bigger do i need to make the box to keep it at 1.8 cubic feet?? thanks

dappa5
05-18-2009, 07:33 PM
ok no links are comming up when you say "this" but send me your max dim's and I'll fix you up

DNick454
05-19-2009, 01:10 AM
so could i just buy a prefab sealed box and than make a port on it???

There are multiple problems with doing that.

1. Ported boxes require more volume than sealed, and prefab sealed boxes are usually pretty tiny.
2. Cutting out part of the box and then adding a port would take up even more internal volume making the box WAY to small for the woofer.
3. Any port that would fit inside a box with THAT little of a net volume would be so small on the port area aspect that the woofer would be choked down and all you would hear is port noise and turbulence.
4. Prefab boxes from bestbuy are outrageously overpriced and cutting it up and adding a port would make it look disgusting.

Not trying to trash your plans, I just don't want you to go out a spend a bunch of money, and it would sound like ****.

zaid990
05-19-2009, 02:02 AM
i think im gonna make my own, and i used a calculator online, and i got the dimensions so that with the ports, i have about 1.8 cubic feet per woofer

alvitae
05-19-2009, 03:20 AM
Here is an idea for you. go find your local cabinet building shop. Have them do what you are unable to. Cut the sheet up. Cut the holes etc. Whatever you don't think you can do yourself.

Then put it together your self and you will wind up with a quality box that you had a hand in for pretty cheap.

DNick454
05-19-2009, 05:14 PM
i think im gonna make my own, and i used a calculator online, and i got the dimensions so that with the ports, i have about 1.8 cubic feet per woofer


The easiest would be to do a common chamber single slot port. Go to www.reaudio.com and use their box calculator. For two 12's with 1.8 cubes each, you'd want around 45-50 sq. in of port area and then fiddle with the dimensions until you get 3.4 cubic feet (net) with a port that's around 50 sq in. area tuned to your listening preference, anywhere between 32 and 38 Hz will be great on music.

zaid990
05-20-2009, 02:15 AM
what would happen if i had 58 sq inches of port space, because thats what i got when i put in my demensions and got it to my frequency ( 36Hz )

csu87
05-20-2009, 02:18 AM
your in Foco, so am I. Hit me up and ill make you a box that will be perfect for those subs.

Sent you a pm

dappa5
05-20-2009, 08:59 AM
The easiest would be to do a common chamber single slot port. Go to www.reaudio.com (http://www.reaudio.com) and use their box calculator. For two 12's with 1.8 cubes each, you'd want around 45-50 sq. in of port area and then fiddle with the dimensions until you get 3.4 cubic feet (net) with a port that's around 50 sq in. area tuned to your listening preference, anywhere between 32 and 38 Hz will be great on music.
and if you use the calc it will give you almost the same dims I did (I just put port in center for looks)just go see csu87 he's in your home town he'll fix you up. besides will be easier w car in front of him maybe he can squeeze some cubes out of your "max dims" good luck


p.s. dnick by the way 1.8 +1.8 does not equal 3.4 lol just bustin your balls lol

dappa5
05-20-2009, 09:04 AM
Dnick454 you still the man though cuz now i can do this
http://i668.photobucket.com/albums/vv50/DAPPA5/IMG00003.jpg:D:D:D:D:D:D:D:D