so confused with port design, plz help

[toneloc]

hey guys /gals new here and I've done a lot of reading and watched more videos than i can count I'm not just posting because I'm to lazy to do the research I'm honestly confused. So I've started A costume fiberglass under seat box for my 4th gen Ram 1500, will contain 2 CT Sounds Meso 10D2s combined net air space -2.0 cu. ft.- on A Skar RP-1500 @ 2 ohm = 1500w RMS, from what I've seen (Dyno videos.) I've seen multiple ported designs
(ex. below in pics.) i have enough gross vol. for the sub and port displacement, box will have to be modified. the broken pencil line in the pic gives me roughly 2 cu ft after sub displacement it is also currenty .75 in to tall in the front and 1.5" in the rear in order to cap w/ a double baffle (1.5'') I can manage/figure all of that out.
I'm trying to determine the most efficient position, style SIZE- 30 sq in?? (do not understand, am I correct that # don't even really matter?) port design for this enclosure. I've used many design programs, apps and calculators. I think id like to do something like the centered slot port or dual flared round ports on the rear corners. One calc. says, 2- 2" Dia. @ roughly 5" would be 36 hz it just doesn't seem right?? any idea how to figure the correct dimensions for that centered port w/the sub specs provided? do yous think the slotted ports would perform/sound better? or dual round ports? Again any dimensions anyone might be willing to help figure or help explain would be amazing because am am beyond confused at this point.

If the box was cut of at the the broken pencil line it would be roughly 2.3 cu ft which leaves room for port area roughly 4x6 x 50in pencil line is the same dimension as white lines on box

View attachment 47568

 

[1aespinoza]

30 sq in?? (do not understand, am I correct that # don't even really matter?) port design for this enclosur

It is an important parameter. What this parameter means is the area of the port. It is the opening of the port in square inches. So the port can be 5x6, 2x15, 5.47x5.47, or a 6" port (3x3x3.14) which will equal 28.27 square inches. Now the Displacement 0.15 cubic feet, you multiply by 1728 (# of cubic inches in a cubic foot). It gives you 259.2 cubic inches. You divide that by 30 sq. in. and you get 8.64. So your port should be 8.64 inches long. For the round port it should be 9 inches long.

 

[toneloc]

It is an important parameter. What this parameter means is the area of the port. It is the opening of the port in square inches. So the port can be 5x6, 2x15, 5.47x5.47, or a 6" port (3x3x3.14) which will equal 28.27 square inches. Now the Displacement 0.15 cubic feet, you multiply by 1728 (# of cubic inches in a cubic foot). It gives you 259.2 cubic inches. You divide that by 30 sq. in. and you get 8.64. So your port should be 8.64 inches long. For the round port it should be 9 inches long.

TY for the reply. if i was to use the round port, could i heat it and throw it in-between a coupe boards in a vice to make it oval shaped. Area would remain the same i would just have a Roughly 4x8 oval. with that being asked the size makes me think the port Air velocity would be pretty high. would flared ends compensate ant put it in the actable rang IYO. i would also like to use the port on each rear corner to attempt to keep the sound centered, so if adding that second port I believe it should be the same size and length, correct?.
would the second port affect air velocity? seems like it may lower it a little but not sure.

 

[1aespinoza]

Area would remain the same

Yes.

me think the port Air velocity would be pretty high. would flared ends compensate ant put it in the actable range

I do not fully understand the question, but if the manufacturer suggests such a big port, it is probably because it has a high QTS. If it is 0.4 and above, it would also work well in a Infinite Baffle setup. Given that, I do not foresee any issues with the port velocity as it will be. As for flares, I have no clue regarding pros & cons aside from the chuffing reduction.

would also like to use the port on each rear corner to attempt to keep the sound centered, s

I have read that bass is not directional, so it would be hard to tell where the subs or ports are located.

believe it should be the same size and length, correct?.

Yes, a port is needed per sub, or you can double the area of a single port.

would the second port affect air velocity? seems like it may lower it a little but not sure.

If this gives you doubt, divide the chamber..