please check for any errors

[davidfre21 5,000+ posts]

i couldnt tell u about the port length, i had help designing mine...

u have plently of time to get ready for the comp //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

u would be in the Stock 0-300

 

[norcalSRTrida 10+ year member]

i couldnt tell u about the port length, i had help designing mine...
u have plently of time to get ready for the comp //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

u would be in the Stock 0-300

hopefully itll all be done by then. ill be going to the shop and gettin my HU this week, then all i have to do is create my box.

you going to be there?

we'll have to exchange info or find out what car you drive so i can keep an eye out

any1 else care to help me dilemma w/ my port length?

 

[davidfre21 5,000+ posts]

oh u know ill be there in the stock 301-900 class.

 

[norcalSRTrida 10+ year member]

oh u know ill be there in the stock 301-900 class.

//content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif sadly enough, i dont know the classes at all.

i just got into car audio nor more than 2 months ago, and been trying to get everything down.

all these class names just seem like #'s to me. lol

drop me a pm a day or two before you go, and ill let you know if my systems done by then.

 

[norcalSRTrida 10+ year member]

no1 has an idea of what my port length should be?

and can some1 give me a discription of what correctional factor is?

 

[bcarpenterfhl 10+ year member]

i have been able to figure out what your trying to tune to...

 

[norcalSRTrida 10+ year member]

i have been able to figure out what your trying to tune to...

2.8^3 @ 30 hz

ive got 25.19" and 24.54 in another program

im about to add those 2 up and / to get the avg and just use that number. lol

any idea

 

[bcarpenterfhl 10+ year member]

you're gonna compete with a box tuned to 30 Hz? Have you figured out the resonant frequency of your car?

 

[norcalSRTrida 10+ year member]

you're gonna compete with a box tuned to 30 Hz? Have you figured out the resonant frequency of your car?

nope. im a newb to box building, i just planned on building a box tuned to what i want and placing it. lol

how do i figure out resonant freq.?

edit:

i dont plan on competing in any comps. and if i do, itd be jsut for the hell of it

 

[bcarpenterfhl 10+ year member]

you usually want to tune close the the resonant frequency of your car. i've never competed, so dont hold me to any of this. but to find the resonant frequency of your car, i believe you place your sub in a sealed box built to specs, then play a sweep of different test tones. then with an spl meter from radioshack or something, figure out which test tone frequency plays loudess (remember to keep the volume on h/u constant). the frequency that played the loudest is your resonant frequency (it usually ranges from 40-55 Hz). Then i believe you try to tune your box a quarter octave below the resonant frequency or something. but ask someone who competes, they'll know more than i do.

 

[msimon 10+ year member]

I think you are measuring your port length incorrectly, I get 28.29" after the correction factor. When you measure length you don't go by the length of the port walls, you go by the length of the middle of the port, like this:

 

[norcalSRTrida 10+ year member]

I think you are measuring your port length incorrectly, I get 28.29" after the correction factor. When you measure length you don't go by the length of the port walls, you go by the length of the middle of the port, like this:

bhcarpenter: i dont have the time nor the $$$ to build a sealed and test, then a ported.

i just want to build 1, then get it over w/

and msimon. you are most probably correct. i did not use the correctional factor. so for a box 2.8^3 @ 30hz, my port length should be 28.29" ?

thank you both for help, and fill me in on any other mistakes.

 

[norcalSRTrida 10+ year member]

im getting confused.

so if i use 28.29" as my port length, do i go 11.25 back ane the next wall 12.54" long?

 

[davidfre21 5,000+ posts]

bhcarpenter: i dont have the time nor the $$$ to build a sealed and test, then a ported.
i just want to build 1, then get it over w/.

that would only be if u planned to heavily compete like me //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[msimon 10+ year member]

bhcarpenter: i dont have the time nor the $$$ to build a sealed and test, then a ported.
i just want to build 1, then get it over w/

and msimon. you are most probably correct. i did not use the correctional factor. so for a box 2.8^3 @ 30hz, my port length should be 28.29" ?

thank you both for help, and fill me in on any other mistakes.

No, I am saying that currently your port length is 28.29". I would just start over as this whole box seems messed up. The port wall and the sides don't add up, .75 + 11.25 + 2 + .75 = 14.75", yet in your drawing it says the side is 14". Also, before driver displacement I get 2.32 ft^3 tuned to 30.5 hz but that is incorrect because your port changes to 1.25" wide after the bend...