OK whipped up an idea for my regular cab truck... I have a sealed box right now but I'm contemplating going ported.

Specs:

16.25 in^2 of port area..

60in. port length

.67 ft^3 for the woofer

That should put it tuned at 32hz, according to the calculator I used online.

The port is facing the passenger side of the cab, sub firing forward. Lemme know what you think. Too many bends in the tube? Too high of tuning for good sq? Not enough port surface area? Would I get alot of port noise? I seem to remember talking to Mike in an email and he said 14 in^2 was all I needed for port area.

I really dont know how its possible to tune a ported enclosure to the specs that are on SS's website. The recommended ported box for the Rli-10 is .45cubes ported to 27hz.. When I plug that into a box calculator the port comes out as needing to be something like 155in long.

Edited July 30, 200718 yr by Unrthdxdream

That should be pretty close. Personally I'd tune lower, but you know me well enough to realize that I would say that. IMO you are also borderline on the port area, but I tend to err on the high side. My Rli8 has 21sqin. and no noise in the car, but the box is in the trunk.

That should be pretty close. Personally I'd tune lower, but you know me well enough to realize that I would say that. IMO you are also borderline on the port area, but I tend to err on the high side. My Rli8 has 21sqin. and no noise in the car, but the box is in the trunk.

Yeah I looked at what it would take to tune lower in my first design.. And the port length was crazy... 60in is still pretty damn long and thats just for 32 hz..What are the specifics on your box? Vol for the woofer and port length? I know yours is an 8 but thats why i though id ask around here as well as over at FSC... plenty of SS guys. What calculator or equation did you use? I tried the port length equation on JL audio's site and got a retarded ass number...

Edited July 30, 200718 yr by Unrthdxdream

My box is .64 and tuned to 29hz. I did the calc's by hand and didn't use an online port calculator as I don't trust any of them.

My box is .64 and tuned to 29hz. I did the calc's by hand and didn't use an online port calculator as I don't trust any of them.

Wanna hook me up with the equation? hahah did you use the one on JL's site? still didnt tell me how long your port had to be to tune that low... is it a trade secret? sorry for buggin ya i just want something to compare to...

I didn't tell you because I don't remember. Somewhere around 95", I also haven't "verified" the tuning via measurement but the response when listening to tones feels pretty close.

It sucks writing equations on a forum but here goes, hopefully you can follow this:

Lv = Length of vent in inches

Fb = Box tune frequency (plug in your desired tuning)

Vb = Volume of box (NET) (cubic inches, to convert from cubic feet multiply by 1728)

r = radius of vent in inches (assuming circular, for a rectangular vent you can solve for r by finding the area of the rectangle and setting it equal to Pi*r*r

Lv = [(1.463 x (10^7*r*r) ) / (Fb*Fb*Vb)] - 1.463*r

lol unfortunately i have gotten good at readin equations like that... i spend way too much time using mathmatica... damn engineering school.

Matlab will be more helpful than Mathematica in the real world. I too learned the wrong one.

Yeah mathmatica is just a tool i use for now i will learn matlab in some later courses..

I am still getting a crazy retarded answer lol. mostly from the step where you multiply the 1.463 constant by 10^7*r*r ... that gives me effing 2.3168*10^36 and no other numbers in the equation can knock it down...

nevermind... now im getting answers. 112 in to get to 29hz.. man thats just so effing long... but i guess that is at the .45 cubs they recommend on their site... it'll be more manageable when i up the net volume of the enclosure

Edited July 30, 200718 yr by Unrthdxdream

i'm also trying to make a box similar to this. does it matter if the bends are 90 degrees or better off rounded? i have a pic of what i'm trying and want to know if i'm doing way too much.

sorry, i don't know how to resize the second pic.

The longer the straight the better, the rounder the curve the better. That stuff looks cool phillip, what is it?

lol. rings i cut in half and card stock. i couldn't find any pvc, abs, or whatever for the size i wanted so i made my own. glassed it and use kitty hair to join it to the wood. after all that planning, i'm back to the drawing board though. the cover for my hatchback is 5" lower than i thought. the damn woofer won't fit!