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SPLluminator
12-28-2008, 12:49 PM
Im planing on getting into some comps this spring and want to start in street a. I bought some HDC3 10's. Now i need to design a box for spl. I am (barely)pushing them with an IA 20.1. Im not sure what the peak frequency of my car is(99 lumina). What is the best method of finding this out? Then, i will begin building a box around that.

kmanian
12-28-2008, 12:54 PM
Im planing on getting into some comps this spring and want to start in street a. I bought some HDC3 10's. Now i need to design a box for spl. I am (barely)pushing them with an IA 20.1. Im not sure what the peak frequency of my car is(99 lumina). What is the best method of finding this out? Then, i will begin building a box around that.

build a simple sealed box, run a sweep from 20hz-100hz . Using a meter you run the sweep at the same volume throughout, where ever the dBs are the highest is your res. freq for the car;)

I hope that helps

SPLluminator
12-28-2008, 12:59 PM
build a simple sealed box, run a sweep from 20hz-100hz . Using a meter you run the sweep at the same volume throughout, where ever the dBs are the highest is your res. freq for the car;)

I hope that helps

Thanks for the quick reply
Ive heard people say that this method is bogus. Is that true? If not, then im gonna do it because ive got the wood for a sealed box just laying around. Ive gotta go to the local shop tho to get it metered:(

bball09124
12-28-2008, 12:59 PM
build a simple sealed box, run a sweep from 20hz-100hz . Using a meter you run the sweep at the same volume throughout, where ever the dBs are the highest is your res. freq for the car;)

I hope that helps

After you do that, you meter the sealed box in an open air environment. You subtract the open air db from the in-car dbs and whichever frequency there is the largest difference is your resonant frequency.

I did a horrible job explaining that, if I wasn't clear I'll attempt to explain it again.

SPLluminator
12-28-2008, 01:02 PM
Ok i think ive got that, but theres gotta be an easier way

kmanian
12-28-2008, 01:33 PM
After you do that, you meter the sealed box in an open air environment. You subtract the open air db from the in-car dbs and whichever frequency there is the largest difference is your resonant frequency.

I did a horrible job explaining that, if I wasn't clear I'll attempt to explain it again.


Ok i think ive got that, but theres gotta be an easier way


he is correct, and secondly, there is an easier way, pick a number and build a box. then hope for the best. Truth be told, with the information you got from us, you will be in the ball park but you will still have to tune and tinker from there. It is definately an art!

good luck

SPLluminator
12-28-2008, 01:42 PM
lol, im just gonna pick a #, im a newb anyways, im not gonna win, just wanna get into it. Ill prolly build a box tuned to 45-55hz and .8ft^3 each

thorshammer1
12-28-2008, 05:32 PM
Wouldnt go any higher than 45-47. You won't be happy with 55. Try a slot port and make it big!
http://i266.photobucket.com/albums/ii249/swoolcot/th_HPIM0401.jpg (http://i266.photobucket.com/albums/ii249/swoolcot/HPIM0401.jpg)
First box had a 7 in wide prt tuned to 47 and did 146.6 consistently.

http://i266.photobucket.com/albums/ii249/swoolcot/th_HPIM0520.jpg (http://i266.photobucket.com/albums/ii249/swoolcot/HPIM0520.jpg)

Next box has a 10in wide port tuned again to 47 and gained 2.2 db to 148.8.

Hope this works or helps.

SPLluminator
03-01-2009, 03:22 PM
Ok this is an old thread but i are bumping it:). Im looking at different options for my trunk. Im running into space issues for a port that big(7-10"). The max dims. of my trunk are 34wx16h. Itll work but there is no space for sound to get into the car. Has anyone ever tried subs up port up/back in a trunk with good results? Jw. Ive got a Daily box that 2cubes @ 40hz but im not gonna get craxy #s with it. Any help would be appreciated.

SPLluminator
03-01-2009, 03:52 PM
What are you guys thinking?

SPLluminator
03-01-2009, 04:25 PM
You not thinking?

basshedz06
03-01-2009, 04:27 PM
i would recommend smaller boxes is better in some cars subs up port back is good while in others its not, thats where testing coming into play, i know in my altima if i do ports back an subs to the side i am louder but i have to get some testing done also to see what it does

GearGuy2001
03-01-2009, 04:35 PM
Can you fold your seats down?

The do subs/port forward and only play it when you fold your seats down

SPLluminator
03-01-2009, 06:10 PM
Subs forward was actually 3dbs lower. I was just wondering if they were facing up if i would do better. The seat go down when i unscrew them(which i always have undone because im constantly changing things.

RAM_Designs
03-01-2009, 06:10 PM
^^^what he said. Fire everything forward and seal the box off from the trunk.

thorshammer1
03-01-2009, 08:58 PM
Subs forward was actually 3dbs lower.* I was just wondering if they were facing up if i would do better.* The seat go down when i unscrew them(which i always have undone because im constantly changing things.Seal it forward as well as sealing the rear deck. If you do this the 3db loss will go away. I can get you dimensions of the box that was in the neon. It had a 7 in. port tuned to mid 40's. Do you have a pic of your trunk for me to look at?

SPLluminator
03-01-2009, 09:04 PM
Seal it forward as well as sealing the rear deck. If you do this the 3db loss will go away. I can get you dimensions of the box that was in the neon. It had a 7 in. port tuned to mid 40's. Do you have a pic of your trunk for me to look at?

No, my equipment is in there so i cant get a good pic.

thorshammer1
03-01-2009, 09:06 PM
I see. I tune mine in the vehicle so I know that I am at my peak.

SPLluminator
03-01-2009, 09:16 PM
Idk. I really dont wanna do the box facing in and sealed off because then i can change out boxes. Im thinking of keeping my IA 20.1 for a little while and competing with a single 10 with the amp at .5 ohms. Just for amatuer. Until i get a better car.