Any plans for a 20 litre cab?

I was refering to the selection of width length and hight. How do you come up with those, Is it a golden ratio?

its got to be heigh enough to fit both drivers and wide enough to fit the largest driver...... no golden rule as such..... and the minimum depth would be just bigger than the largest driver.....

I was under the impression that the dimentions of the cab play a big role on its "response". So it's just the total volume then. Alright, thanks Ben.