ok i made a really long thread earlier and it got erased..... im a lil pissed.. but basically the question was.... box box is going to have about 5.6cu ft each chamber for each sub.... if im right.. but the problem is the port will be about 1.5sq inchs to small... would that effect the tuning, bad? and in what way.... The port will still have about 87-88sq inch port area for each sub...
One other thing... when doing displacments you count the entire area of the port hole as a displacement right? not just the wood that was used?
I think that should be enough port area. You will not be able to notice much difference in tuning. The tuning will be slightly lower if the length of the port is the same. Yes you count the whole area as displacement for the port.
Port displacement is not just the area of the port opening, port displacement is the area of the port x length of the port, plus port wall displacement = Total displacement of the port.
Thanks, i figured the port colume as a whole was the displacement thanks, and yea this is for a daily SPL box, i will be building new boxes and such for it later on this box is jsut to begin with until i get some more time and better weather.
The loudest sub is dynamite. Fill the box with high concentration dynamite all wired in parallel to the amp. Also hook an 8" up so that you can still hear the bass before the real bass hits.
After that, set the gain as high as possible and max out your head unit. Now play a max volume 1mhz tone. Make sure to have your SPL meter inside the car and make sure to be far away as the extreme SPL can be bad on your organs and could kill you if you put enough power on it.
I guarantee you'll have the loudest boom in the neighborhood.
ok after about 3 hours of sitting here i think i came out with somthing that should work..... can sombody go over this math for me, would be greatly appreciated.......
My box is 38Wx32Dx22H and will be 3\4" MDF After the divider board seperates the cabins and my port and sub displacement i get 5.286cu per cabin. The area will be 5inch height (+3\4" for wood so 5.75x16(port depth)x17.87 wide.... 5.75x17.87x16 but the opening isnt going to be the same... the port opening hieght will be 5 inch's(the 5.75 is because the wood space is added when i did displacements) but the internal hieght if the port is 5inchs and the width... 17.875 but the opening will be 5x16.9 will that work nice? FOr the 40hz tuning i was looking for with 16sq' port per 1Cu my goal was to get 84.57sq in port area and i get 84.5sq in with the 5x16.9 opening.... so basically if my port is bigger then the opening... does that matter? Its a pain in the @ss to make it so the port and opening area are the same HxW and have the correct port area... unless there is a better calculator or formula then what i have been using... which no idea the name of formula i used.. just did it from all these tips and things i had... and from a previous box design... which reallly really helped me out in doing this.. i had no idea where to start
But all in all my box is 5.286cu Ft per cabin with 84.5 sq in port area with the port depth 16in with the port area a tad bit bigger then the port opening... does that sound like 40hz tuning.. if not what does it sound like? And do u think a dd9515 will bottom out in the box on 3Krms.... it will be for a daily SPL box... i will design the SQL box later down the road..maybe a lil more smaller and lower tuning..
I would just make each port 5x16 and 18.25 long. This will tune the box 40 hz. IMO it would be much easier to do it this way because the numbers will be way easier for you to measure and cut and the amount of port area you lose isn't really that significant.
Well, if your building this enclosure for SPL and you want something that will sound more musical when your not pounding, make a sleeve port that will slide into the other port that will drop the port tuning. Easy as Pie and a piece of cake to do.
Phil, can you show me somthing about sleeve ports, maybe i can try them..IMO im still a nub in the box world lol
I dont mind the measuring its no biggie for me, stiend would that calcuation still give it 16sq. port for every 1cu ft.? The way im thinking (not sure what making the port longer does) the port area gets smaller on that and would tune it lower?
Well, basically, yeah, if a sleeve was fabricated to fit within the existing port opening the port would be smaller in area and at a lower port tuning.
