pnthr30

I am planning on building a sealed box for a 10" Alpine Type R (SWR 1021d) sub. I have looked and read a bit on the whole process, but I have seen some differing points regarding shape and wanted to see what you guys think. I am clear on the whole size (volume) issue - in my case, my sub suggests between a .5 and a .8 cubic volume box. I want to make a box with around .66 cubic feet internal volume. Here is where my confusion lies.........Does shape matter? I have heard that a perfect cube is a bad idea. I would like to stay away from slanted sides (different bottom and top sizes) because I don't want to have to make angular/mitre cuts. Basically, something resembling a rectangle is easier to make. Many people say that as long as it isn't an exact cube you are good to go, but I have seen several places (for example)
http://www.loudspeakers101.com/BoxCalc.htm

http://www.kbapps.com/construction.html


that talk about the "golden ratio". Is this ratio of side length that important? Will there be a noticable difference? I calculated my side length with this ratio and I don't really like the shape. Also, it appears that the pre-made boxes (Q logic for example) do not follow this ratio. Anyone have any insights?

Also, what gauge speaker wire do you suggest? I am pushing this sub with a RF 250a2.


Thanks!

By the way, the shape I want to use (outside edge to outside edge) is 12 x 12 x 12 (with 3/4" MDF) which gives me an internal volume of .6699 (10.5" x 10.5" x 10.5"). What do you guys think of that? (This is directly from Ti.net )

TTT

For subs, as long as you don't have a perfect cube you won't have any cancellation issues. The size of the waves that subs produce are too big to have any problems.

As for wire gauge, in my experience anything larger than 16 gauge will be perfectly fine.


Also, I'm coming up with a different measurement than you are. I'm coming up with outer dimensions having to be 12 x 12 x 11.8 to have a .66 cubes box.

pnthr30

I just clarified my first post.........I am looking at a perfect cube. Do you think that is a problem? The waves should be long enough that it won't effect them, correct?

rcurley55

A perfect cube is not ideal, but is not a "problem". Take a look at www.jlaudio.com and go to the tutorials section. The sites you listed are for home audio, where you find mid range and mid bass speakers inside cabinets. In that application, theories like the golden ratio are more applicable. The perfect cabinet has no parallel sides, but it's so difficult to build.

Generating standing waves in a car audio enclosure would be difficult and a brace or two or some polyfill will eliminate higher order standing waves as well.

Keep in mind that if you want to net 0.66 cubes for your sub, you have to build the box slightly larger then that - the sub takes up 0.092 ft^3, so really, the box must gross 0.075 ft^3.

To get that size, you would probably want an internal volume of 10.5 x 10.5 x 12, so external dimensions of 12 x 12 x 13.5 (assuming 3/4" mdf)

pnthr30

Thanks guys!

mTeC

If you are too lazy to make a box buy one you dont want to make angle so buy one it's much better with the angle take less space (maybe it's nor your case but general facts) and has more style than a rectangular one.

I also seen boxes with internal division well that's hard to build and I'm not sure of the efficienty.. (my opinion : Get a 12 " Type R it's just so AMAZING I heard a GTS Celica that lives 3 streets in front of me and the bass was just COOL. It's also cool in the car )
-My opinion.