Dual 12 Enclosure Port Help

[bmk6795 10+ year member]

Im gonna attempt my first box build here in a week or two, but i have a few questions first. The box is going in the trunk of my 01 civic. I've been playing with torres box calculator just cant grasp the concept of ports. Dimensions are gonna be somewhere along the lines of 17H 27 W 24D. 17 is as high as i can go but i can go wider or deeper. Wanting to tune to 32-33 hz, right now the port dims are 17H, 2W, 17L. This comes to 4.24 cubes net after displacements but only gives me 34 square in of port area. Now my question is what do i need to do to the port? Also, does the port height need to be the same height as the box? Any help will be appreciated.

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[NASTY08IMPALA 5,000+ posts]

Port needs to be wider...and if ur box is 17" tall the port cant be 17" .it would be 15.5"

 

---------- Post added at 10:22 AM ---------- Previous post was at 10:22 AM ----------

 

If ur using 3/4" wood

 

[bmk6795 10+ year member]

Port needs to be wider...and if ur box is 17" tall the port cant be 17" .it would be 15.5" 

---------- Post added at 10:22 AM ---------- Previous post was at 10:22 AM ----------

 

If ur using 3/4" wood

How does this look? 17H x 31W x 22D



How does this look? If it looks ok why are the port walls "to complex to display"?

 

[NASTY08IMPALA 5,000+ posts]

That looks better

 

[bmk6795 10+ year member]

That looks better

if i were doing sub back port back the port width would be the space between the port wall and the side of the enclosure itself right? also how do i determine the port length? i know it's 28, but what exactly determines the length

 

[NASTY08IMPALA 5,000+ posts]

if i were doing sub back port back the port width would be the space between the port wall and the side of the enclosure itself right? also how do i determine the port length? i know it's 28, but what exactly determines the length

Yes from the wall and 28" from the front towards the back

 

[bmk6795 10+ year member]

Yes from the wall and 28" from the front towards the back

thanks for all the help bro

 

[bmk6795 10+ year member]

Yes from the wall and 28" from the front towards the back

How is it possible for the port to be 28" from the front to back when the depth of the box is only 22"?

 

[NASTY08IMPALA 5,000+ posts]

How is it possible for the port to be 28" from the front to back when the depth of the box is only 22"?

It probably is a L port meaning the total of the 2 lengths is 28"

 

[bmk6795 10+ year member]

It probably is a L port meaning the total of the 2 lengths is 28"

so the wall going from front to back and side to side need to total to 28" and be 3.75" from the side and top correct? Sorry for all the questions but thanks for the help

 

[NASTY08IMPALA 5,000+ posts]

so the wall going from front to back and side to side need to total to 28" and be 3.75" from the side and top correct? Sorry for all the questions but thanks for the help

Yes it should show u the length of both port lengths ..one from front to back then another along the back wall but u cant just make them whatever lengths u want

 

[DukeNut 10+ year member]

Measure port length down the center of the port to the intersection of the other part of the port. 3.75/2 = 1.875, (22 - .75 thickness of backwall - 1.875) = 19.375 is length from front of box to intersection so the smaller side is the difference (28- 19.375 = 8.625)

 

[bmk6795 10+ year member]

Measure port length down the center of the port to the intersection of the other part of the port. 3.75/2 = 1.875, (22 - .75 thickness of backwall - 1.875) = 19.375 is length from front of box to intersection so the smaller side is the difference (28- 19.375 = 8.625)

So the port wall from front to back would be 3.75" away from the outer edge of the box and be 19.375" long and then a piece of wood would connect to the end of that piece and be 3.75" away from the top of the box and 8.625" long right?

 

[bmk6795 10+ year member]

Yes it should show u the length of both port lengths ..one from front to back then another along the back wall but u cant just make them whatever lengths u want

do you think it will be ok with a single baffle? also is it ok if the screws holding the subs in go into the 45s in the front? and lastly are 45s in all the corners gonna be enough bracing or do i need more?

 

[DukeNut 10+ year member]

Think of it as an L and you are looking down into the port. You want to measure starting at the front edge of the baffle (ie put the tape measure lip over baffle edge and run it towards back of box).

Yea the longer port running parallel to your side will end 3.75 from your back wall. your shorter piece will butt to it and be 3.75 away from the back. The side closest to the back should be flush with the end of the longer port and attach inside the longer port. So the short piece will be 6in long (8.625 - 1.875 distance to center of port - .75 thickness of mdf of other port).