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Psyence
10-16-2005, 03:55 PM
Hi, Just built a box for my Alpine Type-R....

I have a total volume of 2.5 cft, and i was thinking about using a square vent, not a slot, but a perfect square...

I would like to tune to 36hz

I have come up with a 3.5"x3.5" port that I figure needs to be....

7.3" long...

Can someone that knows something about this double check my calculations?

Thanks.

PowerNaudio
10-16-2005, 05:27 PM
is that volume internal or external,
is that volume with or without the displacement of the port and sub.
what is the thickness of the mdf wood being used. are you using the same width of mdf for the port walls.
is there going to be any bracing used.

Psyence
10-16-2005, 05:45 PM
That is the total internal volume including sub displacement.

3/4" MDF on port walls

No Bracing, that isnt accounted for already.

PowerNaudio
10-16-2005, 05:47 PM
That is the total internal volume including sub displacement.

3/4" MDF on port walls

No Bracing, that isnt accounted for already.

did you account for the port
displacemet as well?

Psyence
10-16-2005, 05:48 PM
No.

Also, check the dimentions again, i changed them slightly...

But this is the final measurements I came up with...

With the port @ 7.3" 5x5" external dimentions of the port...

would be 2.40

thus making hte port length required....

7.72"

Correct?

PowerNaudio
10-16-2005, 05:55 PM
I have a total volume of 2.5 cft, and i was thinking about using a square vent, not a slot, but a perfect square...

I would like to tune to 36hz

I have come up with a 3.5"x3.5" port that I figure needs to be....

7.3" long....

that about right
did you take into consideration port noise?

Psyence
10-16-2005, 05:58 PM
Well, I was going to round the edges of the port on both ends...

Anything else i can do?

PowerNaudio
10-16-2005, 06:06 PM
Anything else i can do?

yes,
you can increase the port area by at least x3 . rounding the edges may help a hair, but sizing the port correctly will make the difference.

the port length is also going to increase so it makes sense to see how much available area you have for the box, since you may have to go with a bigger enclosure to fit the bigger port.

Psyence
10-16-2005, 06:25 PM
Well...

Ive figured that if I go 2" x 10" x 8.6" slot type port...

I will have a reduced chance of port noise?

PowerNaudio
10-16-2005, 07:01 PM
Well...

Ive figured that if I go 2" x 10" x 8.6" slot type port...

I will have a reduced chance of port noise?

that right there tunes it to like 40some Hz


whats the height of the enclosure? use that for the height of the port.
then do 4"~4.5" inches in width, then calculate the tuning off of that for the length.

Psyence
10-16-2005, 07:35 PM
I cant do a concentional slot port... I have to have it in the middle of the top, because of angles, etc.

I was thinking to make the rectangle shape (the port) and fastening to the top in the middle...

I cant make it so that the port uses the back of the box as one side of the port.

Psyence
10-16-2005, 08:03 PM
Well, now im just stumped....

Xmax = 18.1mm the manual says...

So I enter this into this calculator that i found giving dimentions for square ports... It says for that xmax @ 36hz I need the sides to be 6" or so

I enter that number into the port calculator, and it says 0" for the length...

If I leave it at the 6mm it has as default xmax for 'most subs' it says 3.42" for the dimentions...

So I dunno what to do :)

So basically, i need the square port dimention for the 2.4cuft box tuned to 36hz... and its gotta be somewhere around .... 7-8" in length...

This is the shape of the box, and you can see why I can not have a slot port. The sub is on the angled part facing forward, so the port has to go on that top piece.


http://battlepsyence.com/box2.jpg

PowerNaudio
10-16-2005, 08:31 PM
OK after seeing the kind of enclosure. its a little different but still doable.
now
what is the height of that panel where the sub is going to be on?
are you using a 10" or 12" sub.
what is the width of the box?
and what is the total height of that box?
do you have a more clear pic of the box with some numeric dimensions.

i can help you calculate if i had a more detail drawing or picture of the enclosure.

btw that box looks pretty cool

Psyence
10-16-2005, 08:36 PM
Okay... I ve decided... and it fits.


1.5" x 10" x 9.8" - Non Slot Port

This should be perfect.... Volume after port & sub displacement = 2.42cuft.

Word.

PowerNaudio
10-16-2005, 08:37 PM
whats the tuning freq on that?

Psyence
10-16-2005, 08:37 PM
K, Lemme take a current pic, ill put some dimentions on it.

Sec.

Psyence
10-16-2005, 08:46 PM
Id like it to be 36hz... thats what that should be.

Psyence
10-16-2005, 09:01 PM
Tada...

http://battlepsyence.com/newbox1.jpg
-
http://battlepsyence.com/newbox3.jpg
-
http://battlepsyence.com/newbox4.jpg
-

Excuse the silicone all over, I just wanted to make sure everything was sealed.

Being covered anyways ;)

Psyence
10-16-2005, 09:07 PM
I think I can do a slot port too, they dont have to go side to side do they? As longs as 1 wall is the box itself?

Cause I found this would fit...

2x9" slot port along the back, 7.46" long...

Either, or ... Which would work better, if you dont have a better idea....

Psyence
10-16-2005, 10:56 PM
Well, I made an executive decision ;)

I made a 2" x 7" - Non-Slot Port, 9" Long.

Should be 36.2 or something hz

Put it basically in the center of the top, lots of space betwiin opening and woofer, and lots below, and a couple inches behind...

Welp, I guess tomorrow I will see what happens, good thing is, its pretty easy to change the port the way it is.

PowerNaudio
10-16-2005, 11:20 PM
cool, let us know how you like it.