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View Full Version : help please!!, port for ported box im building outisde



vosschs
12-14-2004, 06:37 PM
im building a ported box right now outsied i have the sides and bottom and front back all on now its all together but the top which i have cut and the port, i want this tuned at around 38hz or so, how would i do that, the dimensions are

25.5 wide 15 high and 21.5 deep

also the port on the front is already cut at 2.5 inches wide i could make it wider but not shorter it would be easiest for me to keep it at 2.5 inches so how could i get this port at 25.5 hz??? thanks!!!

Acidburn
12-14-2004, 06:40 PM
http://jlaudio.com/tutorials/ports/images/Fb.gif
use this formula from http://jlaudio.com/tutorials/ports/index.html and some math skillz and you'll be good to go

vosschs
12-14-2004, 06:46 PM
yeah right ill never figure that out :( please help!

Acidburn
12-14-2004, 06:49 PM
well basically since you have the outsides made but no thought given to the inner port walls and stuff this is going to be difficult

vosschs
12-14-2004, 06:52 PM
well basically since you have the outsides made but no thought given to the inner port walls and stuff this is going to be difficult

****!! think you could give it a try, any where from 33 hz to 43 hz would be good

vosschs
12-14-2004, 06:58 PM
[img=http://img94.exs.cx/img94/1319/ss6rv.th.jpg] (http://img94.exs.cx/my.php?loc=img94&image=ss6rv.jpg)

vosschs
12-14-2004, 07:43 PM
cmon some one please!

vosschs
12-14-2004, 07:59 PM
ttt one more time, id like to get it finished within 2 hours, kinda stuck, thanks!

Scarenius
12-14-2004, 10:39 PM
Use Legos or PVC or something. Start at like... 4 inches long, snug it in there. If it sounds nice, keep it, if it's not enough quality, make the port longer, if it's not loud enough, make it shorter.

That's the redneck way of doing it.

Strecker25
12-14-2004, 10:42 PM
if u must (the formula isnt really hard unless your doing the calculations in your head or somthing) use the www.bcae1.com calc, use trial and error and just see if u can get what u like since uve already started construction

vosschs
12-14-2004, 10:46 PM
**** , i wanted a slotted port, i was going to make the port 2.5 inches wide then 2.5 inches from the back stop the first slot, then the second one 2.5 inches away from the first and stop it 2.5 inches from the front, like my other box but this is almost double the cu ft, so i dont know what it would sound like

Strecker25
12-14-2004, 10:47 PM
not quite getting what your saying, that calc will do a slot port just fine, just figure out which round port diameter is the same area as your slot.

vosschs
12-14-2004, 10:54 PM
not quite getting what your saying, that calc will do a slot port just fine, just figure out which round port diameter is the same area as your slot.



wow i have no idea what your talking about, let me draw the pic to show you what i mean, to see if you could please help me with a slot port

Strecker25
12-14-2004, 10:57 PM
25.5 wide 15 high and 21.5 deep

are these internal dimensions? ill see if i can knock somthing out from what u have already, any idea on driver displacement?

vosschs
12-14-2004, 10:58 PM
i wanted to try and do the slot port on the left, or the right didnt matter, i was going to go ahead and do this on the right but no idea what HZ it would be tuned at , i know almost nothing to do with ports!!

http://img26.exs.cx/img26/9987/ddd3aq.png

vosschs
12-14-2004, 10:59 PM
yes those are the external dimensionts 3.75 cu ft anywhere from 33-43 hz would do if you could do

Strecker25
12-14-2004, 10:59 PM
well if theyre external what is the thickness of your wood

vosschs
12-14-2004, 11:00 PM
.75 , 3/4"

Strecker25
12-14-2004, 11:05 PM
well not counting speaker displacement, using 25.5 x 15 x 21.5 external, i got a 2.998 cubic net tuned to 39hz you will need a length of 14.734. PortArea of 33.183sq inches(with 13.5 high and 2.5 wide port). You could go lower, but youll have to deal with port bends, and im not sure if you want to do that.

vosschs
12-14-2004, 11:08 PM
39 hz is perfect, think you could draw it on paint to show me how its done? thanks !!!!! also i got 3.75 cu ft with audiobahns rec box calc

Strecker25
12-14-2004, 11:17 PM
[img=http://img4.exs.cx/img4/5131/ddd3aq5jr.th.jpg] (http://img4.exs.cx/my.php?loc=img4&image=ddd3aq5jr.jpg)

cant say i didnt try at least

/edit: sorry had to change it quick did the wrong width, its like 3.5 cubes i think

vosschs
12-14-2004, 11:23 PM
k ill try it, and why isnt it like my other box, thats the one on the left of what i drew on page one, with different measurments but the port is the same, with 2 slots?

vosschs
12-14-2004, 11:24 PM
k ill try it at 11.8 inches thanks again!

Strecker25
12-14-2004, 11:25 PM
because the longer the port the lower the tuning, for a 39hz tuning you dont need that length (according to bcae1 at least) idk i just punched in your numbers. not too sure on that wood though, might wanna brace the **** out of it

vosschs
12-14-2004, 11:27 PM
yeah that wood will work , read my work log post it has pics of that box so far,

vosschs
12-14-2004, 11:27 PM
if anyone else is reading, please feel free to put in input

FOSGATE JOE
12-17-2004, 03:11 PM
??????????/ port the *****