PDA

View Full Version : need help on box for 18

playyamxz550
06-23-2011, 01:41 AM
I wanted to do about 6 cubic ft about 35hz so i went onto a website for building a box like the calculations this is what I got 31w,20h,21d,3/4 wood = right about 6 cubic ft, now it says port size but with the 3/4 wood on each side how long would the port have to be and how wide would you say for 35hz?

playyamxz550
06-23-2011, 01:42 AM
the box cubic ft came out to be 6.15864ft to be exact so if someone can find those 2 messurements I need for the port that would help me so much

RAM_Designs
06-23-2011, 07:03 AM
That's 6.16ft^3 before displacements, you want 6ft^3 after sub an port displacements. You're going to need about 7.75ft^3 gross volume if using a slot pot.

hispls
06-23-2011, 09:32 AM
That's 6.16ft^3 before displacements, you want 6ft^3 after sub an port displacements. You're going to need about 7.75ft^3 gross volume if using a slot pot.

^^^

This. Generally add a cube to a cube and a half at least, if you want to go big, add 3 or 4 cube for port, bracing, and sub displacement. I'd suggest 8" round port minimum.

playyamxz550
06-23-2011, 01:51 PM
okay the sub is a dc level 4 xl 18, i was gonna have reqtangle box ported out the back on the left side, sub firing up......so your saying I should get a box thats at least 7.5 cubic ft but then how do I tune the port after sub displacement and 45'ing the corners?

pro-rabbit
06-23-2011, 01:59 PM
The best way for you to learn quickly would be to purchase a design, which gives you 3D modeling to look at as well as explanations as to why everything is set the way it is. It normally also comes with help during your build(if needed) from the person who designed it.

As for you ? though. You figure out your port area and length of your port needed to achieve the tuning you want. Then figure out the displacement of the port, sub, 45s, and any bracing. Add all that to 6ft3 and you get the overall size you need to have the correct enclosure.

playyamxz550
06-23-2011, 02:03 PM
Thanks I have a good design its just a normal slot design box, now i got new messurements 34w,22h,21d...3/1 mdf...cubic ft=7.51845. now after I add sub and port and 45s, and I guess 2x4 bracing? or metal rods.........this setup has to be someone strong its running at 1ohm on a brz2400 thats another things i dont understand is box rise on the ohm?

RAM_Designs
06-23-2011, 11:32 PM
Don't worry about box rise with a daily box.