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pnthr30
06-04-2004, 10:04 AM
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 the 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 in sound? 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) (internally 10.5 x 10.5 x 10.5) which gives me an internal volume of .6699. What do you guys think of that?

helotaxi
06-04-2004, 10:39 AM
The shape is not very important. You will not hear a difference as long as the enclosure is solidly built. The "golden ratio" is more important when you are dealing with woofers that are playing a larger spectrum of frequencies rather than subs. In the higher frequencies, you have to start worrying about standing waves in the enclosure. Not so with the low freqs fed to a sub.

ramos
06-04-2004, 10:42 AM
As far as the shape of the enclosure goes. It could be a perfect cube that small. It isn't big enough for a standing wave to form in. As for wire guage you might as well use 12ga it's pretty cheap. :)

ramos
06-04-2004, 10:42 AM
D@mn I'm old and slow . :)

slick rick
06-05-2004, 12:38 AM
The shape is not very important. You will not hear a difference as long as the enclosure is solidly built. The "golden ratio" is more important when you are dealing with woofers that are playing a larger spectrum of frequencies rather than subs. In the higher frequencies, you have to start worrying about standing waves in the enclosure. Not so with the low freqs fed to a sub.

so if i have my lpf at 80 there is no chance of a standing wave even in a perfect cube box? and also how much of a difference would the sound be between these 2 boxes... not going by cuft but by how the subs are facing and the shape.
http://bigdogaudio.com/proddetail.asp?prod=122SLREV
or..http://bigdogaudio.com/proddetail.asp?prod=BIG122SQR

just curious between the hatchback style and the second box which is basically a cube shape for each sub.

pnthr30
06-07-2004, 10:48 AM
Thanks for the input (and knowledge) guys, I appreciate it!