box for an sx 18"

[coolahan 10+ year member]

For an RE SX 18"... just wondering if you guys think this will work out nice..

Sub is going to be playing upwards.. port going out back..

Number of subs : 1

Box type: Vented

Box size: 7.000 ft^3

Tuning frequency: 34.00 Hz

Wood Thickness: 3/4"

W: 36"

H: 20"

D: 20 1/2" (little less than half)

Vent: 1 vent

17.34 in length

34.50 x 2.75 port dim.

What do you think? Input is greatly appreciated.

Click to read more...

 

[90accordman 5,000+ posts]

should sound good, i think Mannyb is 8cu and it hits hard as hell, but his sub fires frontward as well as the port.

with those numbers (my math sux) i didnt get 7 cubes though

 

[coolahan 10+ year member]

should sound good, i think Mannyb is 8cu and it hits hard as hell, but his sub fires frontward as well as the port.
with those numbers (my math sux) i didnt get 7 cubes though

WinISD did the sq ft math... and does making it fire frontward really make that much of a difference? .. cause i wanted to look in the rear view mirror and smile when i saw the EXCURSION! but i mean i could make it a little bit taller and make it fire frontwards if it makes a noticable difference.

 

[90accordman 5,000+ posts]

ive never heard a blazer, he runs a ext cab s10, so theres really no choice on where they port. if im correct your looking at a box like the one in bamaboy's sig?

 

[90accordman 5,000+ posts]

i used this program http://www.caraudio.com/forum/showthread.php?t=173468&highlight=volume+calculator

inputted 36/20/20.5 to get the number i got before porting and displacement.

8.54

 

[coolahan 10+ year member]

i used this program http://www.caraudio.com/forum/showthread.php?t=173468&highlight=volume+calculatorinputted 36/20/20.5 to get the number i got before porting and displacement.

8.54

maybe WinISD takes out for porting and sub displacement?

can someone run over them numbers and make sure everything i posted is right?... i'm not that great with math...

 

[MikeyB 5,000+ posts]

That box is only going to be 7.018, before port and sub displacement fyi.

 

[MikeyB 5,000+ posts]

also, running the port like you would like too you are looking at about 1.2 cube of port disp, and the SX 18's disp is about .2 if I remember correctly.

So basically that box will end up being about 5.6 cube.

 

[j3bus2k3 5,000+ posts]

With those EXTERIOR dimensions give your getting 7.0177 GROSS volume. Thats before driver and port displacment. Readjust your numbers bro.

EDIT: Beat me to it Mikey //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[coolahan 10+ year member]

do you guys think that firing the sub forward would be a noticable difference over firing it upward.. and i can make it a couple inches taller to get some more sq ft... but i mean the ideal space for the sx 18 is 5.6ft^3 anyways isn't it? thx for doing the math guys..

 

[90accordman 5,000+ posts]

some of these guys with 18' SX are running 7-8 cubes

 

[PowerNaudio 10+ year member]

i think that is realy vehicle dependent when it comes to where you point the subs.

in an suv i have had great success installing them firiring them upward. but since there is so much open area in an suv. i realy dont think it will make that much of a diffrence.

a good way to test is if you have a small enclosure and sub, power them up and see what works best and go with that.

 

[60ndown 10+ year member]

id put the sub and the port on the same surface if you can, then you can face box up or forward or backwards depending on what sounds best, with the sub and port on different surfaces your risking weird phaseing / cancellation issues ( i think?)

 

[coolahan 10+ year member]

screw it.. ill fire it forward.. and make the box taller :O

how do i calculate port displacement

 

[iamamp3pimp 5,000+ posts]

the only numbers taht i looked at was the H x W of the port, and thats ging to have some nasty turbulence as well as lose much output due to the ratio being so far off.

you dont want to go over 1:9 in most cases.