4 sundown x 18 box help

[robby512]

im looking for a design for a box for 4 sundown x 18 it will be going into an 05 f150.

powered off of only 2 hifonics brutus 1200 watt amps hopefully upgrade to bigger soon.

max dimensions are

53 long

41 height

27 depth

im looking for port forward sub forward just about the only way it would work.

id like if possible for port to be in the middle but if it will make it to much bigger either side will work.

thanks

that is outter dimensions

[robby512]

Actully im looking into a bandpass box if possible

[Guest]

port forward sub forward? might as well do a wall.

[robby512]

yea im between the both I like the idea of a band pass I like the idea of the sub inside the box so there not smacking against my back seats. but down side is the box has to be huge and I don't have much more than 29 cubic feet. and the ported one sundown said 25 cubes after displacement so that one would be much easier. sundown calls for 300 square in of port area

[Guest]

dont put the box so close to the seats and dont move the seats backwards. you wont hit the woofers then.

[robby512]

Yea thats what im trying not to do but it will still be a fairly tight squeeze. So bandpass= bad idea might as well just do a wall

[robby512]

How do you find out port area it would be port opening so width x depth right?

[robby512]

I was wrong after research it is height x width

so after contacting sundown for there recs

sundown recs

5.5 cubes per sub

300 sq in of port area

tuned to 30 hz

.25 for woofer displacement

so my numbers and procedures

I started with creating a sealed box and will add the port in

inner dimensions 43.25L x 40.25H x 23.25= 23.42 with woofer displacement it will be 22.42 cubes

now I want to create the port

300 sq in port area divided by 41(total height)= 7.31 so I did 8 nice even number

now to create tunning and length I go to this website

http://www.carstereo.com/help/Articles.cfm?id=31

enter everything 4 subs 18 icnh volume of enclosure I do before displacement and port correct me if im wrong this is the part im not sure of so I use 23.42 cubes

height is 41 and width of port is 8 and I come up with I want to tune it to 35 hz and then get 15.86 long port everything sound good?

[CleanSierra]

Your port that you listed will displace 3.29 cubic feet of airspace. That will effectively raise your tuning by quite a bit. You need to factor in the port displacement when figuring for your NET volume that you need to tune.

[robby512]

ok so the only place I went wrong was with the net volume because net is the whole thing combined. so my net volume before any displacement is 26.71. so my port length should be 21.82 so I will put a bend somewhere in the port so we went 8 inches all the way around correct so the bend will be at 19 to leave me with 8 inches all the way around. now sundown recommended that I tune to 30 hz didn't ask what I was aiming for weather spl or just a burp car they said that would give me best result. but Is there a better I just want something that is loud as hell as efficient as possible.