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View Full Version : Box design for fi Q 18 done need the "go" signal



Xprime4
12-16-2008, 08:31 AM
after losing some hair, some patience, few hours and some sleep, i finally think I (with the help of few) think i've got something ok. I ain't good with design software so there won't be any pics before the build start but i just need a confirmation on what i'm doing :p:

Box will be 37,25 width x 21 height x 22 deep = 8.261 ft/cu before all displacement
Sub = fi Q 18 (27mm xmax) and .24 ft/cu displacement
Tuning expected = 30-32hz no more/ no less

Power will be around (+/-) 1500 watt rms from bxi1606d @ 1ohm. I may set it around 1400 for safety purpose.

Aeros port will be pvc tube from home depot of 4 inch. (i think it's internal)

I've used carstereo calculator but still... they told me i need at least 12.99 inch of minimum diameter (i'm at 16) and minimum 132.53 inch of port (i'm at 754.93???:confused:).
Calcul: P x 2square x 13.01 x 4 aeros = 755inch/cu.
The 13.01 comes from carstereo calculator for 32hz in 8.3 but i'm not sure i need to input the net volume (after sub/port displacement) or the total internal volume before all displacement :confused: :confused: :confused:

The aeroports will be on the left and right side of the box 2 per sides. Sub facing the roof of the accent 99 hatchback.
There is no other way of doing it coz of aeros cleareance issu.

I know i need some kind of bracing to help the aeros straight, what could i use? I only got acces to a local home depot :crying:

How will the bracing displacement affect the tuning freq? should i make the port longer/shorter and am i doing something wrong? If i get the start signal i may start the box building this afternoon....

Please help a poor guy with no selfesteem when it come to tuning calculs.

Rashaddd
12-16-2008, 10:36 AM
Oh boy.......

Xprime4
12-16-2008, 10:38 AM
Oh boy.......

oh boy isn't a lenght:rolleyes:
oh boy what?

Rashaddd
12-16-2008, 10:39 AM
oh boy isn't a lenght:rolleyes:
oh boy what?

You sure about that?

Xprime4
12-16-2008, 10:42 AM
3.14 x 2square x oh boy = fial... pm me if you want 5 bucks with an accurate answer

snoopdan
12-16-2008, 10:46 AM
You wont need to brace those areos with anything more than a shitload of liquid nails.

Xprime4
12-16-2008, 10:48 AM
You wont need to brace those areos with anything more than a shitload of liquid nails.

really? what about the box? will an 18 destroy it if it's well done with my dimension?
rashaadd read your pms

Rashaddd
12-16-2008, 10:50 AM
3.14 x 2square x oh boy = fial...

Now you're catching on

4 4" aero's need to be ~15 inches long each

This gives you 7.6 cubes net after all displacements @ 32hz

and you have 50 sq in of port

you're welcome

RAM_Designs
12-16-2008, 10:54 AM
Don't worry about what the carstereo.com thingy says about minimum port diameter and/or area. If you're doing a slot port, 12-16in^2 of port per ft^3 is fine, you can probably get away with 10in^2 per ft^3 if using a PVC pipe, and maybe as low as 6-8in^2 per ft^3 if using aeroports. I've always used slot ports...they're cheaper and add bracing to the box, win-win in my book.

Xprime4
12-16-2008, 10:58 AM
thank you all! I'll now be able to do something with some confidence. is there a problem of the aeros are facing each other (those on the left panel in front of those on the right panel) facing each other...

Xprime4
12-16-2008, 11:01 AM
Don't worry about what the carstereo.com thingy says about minimum port diameter and/or area. If you're doing a slot port, 12-16in^2 of port per ft^3 is fine, you can probably get away with 10in^2 per ft^3 if using a PVC pipe, and maybe as low as 6-8in^2 per ft^3 if using aeroports. I've always used slot ports...they're cheaper and add bracing to the box, win-win in my book.

this is my 3rd box. the other two were slot and i this time around, i wanted to try something new.

Will i need some kind of bracing or it should be fine?

RAM_Designs
12-16-2008, 11:02 AM
this is my 3rd box. the other two were slot and i this time around, i wanted to try something new.

Will i need some kind of bracing or it should be fine?

It never hurts to brace something. If you have any doubts just go ahead and do it; at least you'll have peace of mind.

Rashaddd
12-16-2008, 11:03 AM
I'd just add a couple wooden dowels to the box where you can and where seems fit

Xprime4
12-16-2008, 11:06 AM
I'd just add a couple wooden dowels to the box where you can and where seems fit

check yo paypal account :greedy: hope you love canadian mony :laugh:

is there any thing wrong with the port facing each other ? there won't be a lof of space between to two. maybe i'll be able to put them few inch away from each other

Rashaddd
12-16-2008, 11:32 AM
check yo paypal account :greedy: hope you love canadian mony :laugh:

is there any thing wrong with the port facing each other ? there won't be a lof of space between to two. maybe i'll be able to put them few inch away from each other

Try to have 8 inches in the middle between them, if not, I'd just put them all on one side if they'll fit

Xprime4
12-16-2008, 11:53 AM
ok thank man