trying to understanded ported boxes for brahma 10"

[impulsebrklyn 10+ year member]

Im trying to build a ported box my first. Ive built 4 sealed so I know how to build a sub box. I want to build a box 1.25 cu ft ported to 35hz. I choose 1.25 cause that whats recommended by adire. Now does that recommendation include port volume?????

What ive found is i need a square port 2.659x2.659 and 9.388 long to get 35hz. Does this sound right? I dont know hot to calculate this kind of stuff is there a way to get the numbers even or some of them???

Where does most of the bass come from the port or woofer?

Oh the woofer is getting 1000watts

Ok last question this one i really dont think will matter. But i would like make the back of the box alittle strange. Here is a picture from the side would this be a problem?????

Click to read more...

 

[impulsebrklyn 10+ year member]

help please

 

[RMKrider1 10+ year member]

That box design will work just fine!! If you don't mind that your port is rectangle shape you can make it 2.75x2.5 and 9.88 long. This will also be tuned to 35hz!

 

[ructwenty2 10+ year member]

just because adire recomends 1.25 cubic feet doesnt mean you cant go bigger. if you have the room you probably should. go to http://www.linearteam.org and download winISDpro if you want a program that will tell you the exact dimensions for a box for your needs. it helps a lot

 

[Savant 10+ year member]

If you get WinISD and want the box dimensions, you need the beta (older).. and the box will be square.. if you get the Alpha (pro, newer) it doesn't do box calcs (not the build I have anyway)..

but, that's moot.. you know the shape you want.. that's all that matters.. Now, you can put in the specs on the sub (might be in the existing database).. then you adjust the box volume and tuning freq until you get a curve you like (on the transfer function graph)..

Then you can look at the port tab and set the dimensions (diameter or if 'square' the sides) and number, it tells you the length... look at the 'rear port air velocity' graph while you do that.. try to stay under (I believe) 20 m/s..

All you have to do is decide what sizes you need for sides etc to make the volume you put in.. keep in mind that the ports, if inside, have to be ADDED as volume to your final box size.. though, it seems that the ports can be external.. then you make the box the 'size' you put in the prog.. and have the ports out of the box..

Hope that helps.. OH.. and set the 'watts' on the signal tab too, and watch the 'cone excursion' graph to make sure you won't bottom out the sub.. I have a 500 rms sub (in sealed recomended box).. at the ported box I want, I can only run 350 watts to it.. but, at 30 Hz, it's better than the 500 in a sealed..

k...

 

[impulsebrklyn 10+ year member]

i need help with the lengths and dimensions of this box. i know it looks like this but what are all the measurments

this is was trixters said

Actually the port would have to be 41.75" long to make up for the port end correction factor. If not the sub will see the rest of the wall (from the end of the port to the corner of the box) as part of the port. The correction factor is found by dividing the height of the port in half and adding it to the lenght: 37 x (9.5 / 2) = 41.75. Also remember when measuring the port to measure down the center of it.

what the hell is port end correction factor?im starting to get pissed here. When i called adire they told me 37 inches long and it didnt mater what direction the port went in. SO if the god **** port is suppose to be 41. 25 inches long my half built box is now garbage