Box port in^2 question. i know this is asked a lot

[killerc998]

I hate being that person just wanting answers. Been reading and doing research for the answer. Just trying to make sure I'm correct. This will be a blow through on a regular cab s10. The system will be 4 ct sounds strato 2.0 8s wired to 1 ohm, running off of a t1500.1D. The box is going to be 5 cubes after displacement. Everything will be ran on 1/0 will have 2 batteries. I will have 2 ports that are 6" pvc and 14.66" long. This gives me 56.52in^2 of port. I know I can use winid ( I believe that is it). I down loaded it but can not figure it out. Its the driver part that is odd for me. And the spec sheet that came with sub only tells me half of the numbers I need. Thanks in advance.
Chris

[Joe X]

If you can picture or scan the manual I could run the parameters, I will say that 1.25 net volume for an 8" seems pretty high but then I have not seen any specs on that particular driver.

[hispls]

The ONLY numbers you need to model in WinISD are Fs, Qts, and Vas. Pay attention to the units! Vas may be cubic feet in your manual but IIRC it defaults to liters in WinISD. Cone area also may be in metric by default in WinISD.

I won't comment on your port area because I've never played with 8's.

[killerc998]

I know its a little bigger then recommended, recommended is .8 ported. Only spec I remember is the xmax, which is 12.5, also after doing some more measurements this weekend I'm prolly gonna build it to 4.5 cubes. But I'm gonna figure out WinISD and get my final box. Thanks hispls for the numbers I need to use.

[DLHgn]

If you get the program up and running make sure to check out the port velocity graph. Your velocity should be under 30 m/s otherwise you'll start running into port noise (could start happening before that in some situations). Also make sure you change the amount of power you plan on running in the program. I believe it defaults to 1 W which doesn't really help you when looking at the port velocity graphs. Also, I would check out the cone excursion graph. Can give you an idea of how your subs will do at that power over the frequencies you plan on playing them at.

[killerc998]

Ok Thanks. This is actually the first build iv looked in to all aspects. The others I got box size and a port. Trying to actually get the most out of it this time.

[killerc998]

Fs 48.04Hz qts 0.508, vas 7.05 qes 0.57, qms 4.42, spl 83.2, xmax 12.5mm coil size 2, power by website 400/800, by paper 300/600

[killerc998]

I think iv figured it out, Its gonna be a 4 cu ft box after displacement tuned to 38hz with 2 6" x 22.75" ports, port will come out of the box about 5" which puts it in the truck and not the blow through (undecided on flair) Will be the 4 8s powered by 1500 rms. Port velocity is a hair under 29 ms @ 90^oF. I will run the ports on the top of the woofers so the woofers will be slightly hidden by the seats and center console. I would of liked a little more box volume but I couldn't get the port flow down below 30ms with out having ridiculous numbers. I believe I calculated this right.

[DLHgn]

If you want the velocity to go down, increase your port area. I believe tuning lower and having less net volume will also decrease port velocity (I may have it backwards).

[killerc998]

I started at 5 cu ft and went down to 4, same as I started at 40 hz and went to 38, might move to 36 haven't decided on that yet. Same as I'm looking at if I can fit it do 2 8" ports and really bring velocity down. I know using the winisd when the temp is cooler it had a little lower velocity at a bit under 29.