PDA

View Full Version : Another check my box calculations with pics (sketchup) post



amedeuce
04-02-2005, 08:52 PM
This is for a 12" magnum
I'm hoping that I did this right and the box is around 1.8 cubes net tuned around 30hz.
the box is 24x16x17 outside dim. WIth 3/4 inch mdf.
The port is 14.5 x 2 and around 48 inches of port if I measured correctly.
Here are the sketchup pics


Look of box
http://gallery.caraudio.com/vg/1/1/0/0/4/1.8cubes30hzwithsubcutout.jpg


Outside dimensions
http://gallery.caraudio.com/vg/1/1/0/0/4/1.8cubes30hzisoview.jpg


Top View
http://gallery.caraudio.com/vg/1/1/0/0/4/1.8cubes30hztopview.jpg


side view
http://gallery.caraudio.com/vg/1/1/0/0/4/1.8cubes30hzsideview.jpg

Rawr-DQ
04-02-2005, 11:26 PM
**** you! What program did you use to do the mockups with, btw looks nice.

amedeuce
04-02-2005, 11:43 PM
sketchup

GCAdidas13
04-02-2005, 11:49 PM
lol ameduce... my greatest condolences for not being able to design you one.. i still don't have AutoCAD on my computer, or else I would have designed you one already :)

Very sorry! if you still want me to, i'll try to download a copy and get one done for ya :)

amedeuce
04-03-2005, 12:15 AM
lol ameduce... my greatest condolences for not being able to design you one.. i still don't have AutoCAD on my computer, or else I would have designed you one already :)

Very sorry! if you still want me to, i'll try to download a copy and get one done for ya :)
well are you saying this isn't right?

GCAdidas13
04-03-2005, 12:48 AM
well are you saying this isn't right?
No i haven't checked it. I'll run it through right now...

volume before sub displacement: 1.85 cubes
i'll take out .07 for sub (that's the actual displacement for SI Mag 12's

if you have 1.78 cubes after displacement, and your port is 48 inches, you have a tuning closer to 28.5 hz.

checking your port length measurement...

vertical one: 15.25 (this is from the opening to halfway through the joint)
horiz one: 2.75 (halfway through first joint to halfway through second joint)
vert two: 13.5 (halfway through second joint to halfway through third joint)
horiz two: 2.75 (you get the idea...)
vert three: 13.5
horiz three: 1.75 (halfway through last joint to opening of port into box)

add all together and get 49.5

you have a 1.78 cubic foot box tuned to 28 hz after you drop the sub in.

This is all straight from WinISD

if you want a different tuning, design a new one and take off about 5" of port. That will probably get you to 30hz

amedeuce
04-03-2005, 01:01 AM
No i haven't checked it. I'll run it through right now...

volume before sub displacement: 1.85 cubes
i'll take out .07 for sub (that's the actual displacement for SI Mag 12's

if you have 1.78 cubes after displacement, and your port is 48 inches, you have a tuning closer to 28.5 hz.

checking your port length measurement...

vertical one: 15.25 (this is from the opening to halfway through the joint)
horiz one: 2.75 (halfway through first joint to halfway through second joint)
vert two: 13.5 (halfway through second joint to halfway through third joint)
horiz two: 2.75 (you get the idea...)
vert three: 13.5
horiz three: 1.75 (halfway through last joint to opening of port into box)

add all together and get 49.5

you have a 1.78 cubic foot box tuned to 28 hz after you drop the sub in.

This is all straight from WinISD

if you want a different tuning, design a new one and take off about 5" of port. That will probably get you to 30hz


Thanks!!! So I was (am) very close to what I'm looking for..
Can I just knock off 5 inches from the first part of the port.
And I already had the sub displacement figured in at .1 cubic ft..

SPL140.2
04-03-2005, 01:10 AM
Looks similar to the deathbox.

amedeuce
04-03-2005, 01:11 AM
Looks similar to the deathbox.
??

GCAdidas13
04-03-2005, 01:12 AM
Thanks!!! So I was (am) very close to what I'm looking for..
Can I just knock off 5 inches from the first part of the port.
And I already had the sub displacement figured in at .1 cubic ft..
Yea man I just did the figuring... You'll be really close to 30. Like 29.5 hz, and that's a good tuning.

Make the piece of wood that is nearest the inside of the box 5" shorter. This one:

http://img93.exs.cx/img93/2008/18cubes30hzsideview5lf.jpg

amedeuce
04-03-2005, 01:13 AM
Thanks again...
I'll post pics of the build when I get time to build it...

JimJ
04-03-2005, 03:55 PM
Looks similar to the deathbox.

Decware's Deathbox...

http://www.decware.com/newsite/mainmenu.htm

Works off a little different design; your box is the common labyrinth slot port design, allows a lot of port length in a small area.