6 replies to this topic

[strong*I*bumpin]

Gnome seeing ur a box builder maybe u can verify my dimensions,I made a box thats 36 x 13.5 x 15(external).The port is 3 w x 12h x 38L(tuning around 30-32hz?) ,how's this sound to u?...Is the box too big?....I can cut it down from one side but thats it,thanx in advance for ur input!

[GnomeAudio]

The outer diminsions of the box work out to 3.234
The port displaces 0.792
The wood that creates the port displaces 0.194
The sub itself displaces .2

The total internal volume after all displacement is 2.148, which is right on the money (nick recommends 2.0 @ 29hz).

Good job....but next time I'm not gonna do your math for you

[strong*I*bumpin]

The outer diminsions of the box work out to 3.234
The port displaces 0.792
The wood that creates the port displaces 0.194
The sub itself displaces .2

The total internal volume after all displacement is 2.148, which is right on the money (nick recommends 2.0 @ 29hz).

Good job....but next time I'm not gonna do your math for you

I appreciate it Gnome,the #'s u got are very close to what I got. I think I got this box building thing figured out ,some what.Gonna order the carpet tomorrow ,I'll post pix as soon as I'm done ....thanx a mil,G!

[cjj2d]

how do you calculate internal volume from the external dimensions? and what about displacement? and tuning?

I decided to try my hand at my first box today and used the dimensions Gnome posted for a 15XXX, the only thing is I made a first timers screw up and now the dimensions are off a little bit, not much though. so now I just want to find a formula to use to try and figure out what I have here.

[dave_Edwards]

Well----it is easier to just find out for yourself----

http://www.the12volt...io/boxcalcs.asp


there ya go---


Dave

[GnomeAudio]

how do you calculate internal volume from the external dimensions? and what about displacement? and tuning?

I decided to try my hand at my first box today and used the dimensions Gnome posted for a 15XXX, the only thing is I made a first timers screw up and now the dimensions are off a little bit, not much though. so now I just want to find a formula to use to try and figure out what I have here.

let's assume your width is 36". If the wood is .75" thick, the inner width would be 34.5 (36-1.5) because the sides of the box would each subtract .75".

If the height is 16 for example, you'd again subtract 1.5 for the top and bottom baffles, and get 14.5. Lets also assume the depth is 12" which would yeild 10.5" of inner depth. Now we multiply these numbers (34.5*14.5*10.5=5252) then divide by 1728 (the number of cubic inches in a cubic foot) to yeild 3.04 cubic feet.....

but if you don't like math, you can always use the calculator dave suggested

[cjj2d]

what is the displacement of a 15" Mag?