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 bad. 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 )


Modified by pnthr30 at 4:00 PM 6/4/2004


Modified by pnthr30 at 4:06 PM 6/4/2004

 

hmmmm, never heard cube shaped boxes are bad. I would use a 12-16 gauge wire from the speakers to the amp. Good luck.

 

Cubes are bad because of standing waves, but in a car subwoofer there is no need to worry. The box cannot be big enough to get standing waves in the subbass range

Just build it in whatever shape you want.

 

wrong, you can get standing waves in car sub boxs . any box that has parellel surfaces will have standing waves. That said, in a car there are other things that will give bigger problems making bass. Follow these paramiters, box can be any shape you want ,[ avoid the "cube" one angle is good,more is better] use 3/4" and 1" MDF [ 1" for baffle serface you mount sub to and sides,3/4" for rest of box] pre drill, countersink,glue and screw the top,back,bottom and front to sides[ this gives you a 1" surface to screw into] when predrilling/countersinking do it at an angle[this avoids spliting the MDF] use a corse wallboard screw [also avoids spliting] Use router to cut hole [ be exact on diam. speaker should just fit] reses speaker into the 1" MDF about 1/8" to 1/4" [for better seal, the MDF is much softer inside then on suface and makes better gasket] install bracing [1"/1"/1" blocks of MDF glued along all seams 4"or 5" apart and serface to serface if you have large surfaces] seal inside of box[MDF is very pouris] with sealer or a spray dynamat.Silicon all seams inside box.Do not forget anything you put into box including sub uses up volume. Use 12ga seaker wire . bolt box into car for best sound. Take my word for it, been doing this for 30 years hope this helps 94 ps dont forget to predrill speaker mounting holes and use a 10# panhead screw