1. ## is a 4" port enough for a 12" bm???

i am building a box tomorrow and it turns out i have the room to make it a ported box so i want to go that route.

the box will house 2 12" si BM's
there is no good area to place 2 ports next to each other so i am planning on seperateing the 2 subs and each chamber will have a 4" pvc port

does this sound like it would work?

i will have some pictures of what i am trying to do in a little while

Thanks,
~Magick_Man~
Last edited by ~Magick_Man~; 01-12-2007 at 11:52 PM.

2. ## Re: is a 4" port enough for a 12" bm???

here is the basic idea i have right now.
it might change a bit but that is pretty much it.

so if i dont make 2 seperate chambers will the subs really utilize the area in the middle?

Thanks,
~Magick_Man~

3. ## Re: is a 4" port enough for a 12" bm???

you need double that port area.

have fun trying to make it fit

4. ## Re: is a 4" port enough for a 12" bm???

heh, that truck will be happy after you are done though

5. ## Re: is a 4" port enough for a 12" bm???

Originally Posted by xluben
you need double that port area.

have fun trying to make it fit

i am using a port calculator and for 2 4" ports in a 2 cube box tuned to 34 it says they need to be 26.xx"

is that each?

if it is then that *****.
because i can fit in up to 14" long ports.

would i be better off with 2 3" instead of 1 4" ?

~Magick_Man~

6. ## Re: is a 4" port enough for a 12" bm???

Originally Posted by bdawson72
heh, that truck will be happy after you are done though

Yeah that guy is going to be very happy.

7. ## Re: is a 4" port enough for a 12" bm???

Originally Posted by bdawson72
heh, that truck will be happy after you are done though

8. ## Re: is a 4" port enough for a 12" bm???

this should be a little better.

25sq-in of port per driver

~Magick_Man~

9. ## Re: is a 4" port enough for a 12" bm???

did yo use those port tubes on NoLimits box?

10. ## Re: is a 4" port enough for a 12" bm???

Originally Posted by 10W3dodge96
did yo use those port tubes on NoLimits box?
no i used a mdf slot port on his.
i am trying to stay away from that on this box because i dont want to mess with angling the port like it is on your box.

and i have a ton of 4" pvc pipe so i might as well use some of it.

~Magick_Man~

11. ## Re: is a 4" port enough for a 12" bm???

um, what's the volume of the box (after displacement) and how long are the ports?

adding two ports like that (and keeping them the same length) is going to make the tuning A LOT higher (10hz +) possibly.

12. ## Re: is a 4" port enough for a 12" bm???

yeah, thats probably not going to work... the port calc is EACH port, so adding more is just making your problem worse

13. ## Re: is a 4" port enough for a 12" bm???

Originally Posted by xluben
um, what's the volume of the box (after displacement) and how long are the ports?

adding two ports like that (and keeping them the same length) is going to make the tuning A LOT higher (10hz +) possibly.
i dont have the exact number yet but i have about 2.2ish per driver after the port is taken out.

i was looking at a single 4" at 11.xx" long which would supposedly give me 34hz with a 2cube box
now i am looking at 2 10.12" long with 2cubes after displacement which should give me ~36hz

i will end up with as close to 2.0 per chamber after the port and sub is taken out.

~Magick_Man~

14. ## Re: is a 4" port enough for a 12" bm???

Originally Posted by PatFitz9
yeah, thats probably not going to work... the port calc is EACH port, so adding more is just making your problem worse
yeah i figured that.
i was using one at 11.xx long shooting for 34hz
now i am using 2 at 10.12 (i think) shooting for 36hz

~Magick_Man~

15. ## Re: is a 4" port enough for a 12" bm???

so i guess the real question is will 2 4" ports 10.14" long in a box 2.0 cubes after displacement give me a 36hz tuning?

i am judging this off the port calculator from carstereo.com

~Magick_Man~

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