Originally Posted by johnrclark
Given that the ~ 2.5 cubic foot enclosure is about the right volume for a single 12-inch driver, I reckon that it is also about right (to first approximation) for 2 drivers in a push-push configuration. Each driver would "see" an enclosed volume of ~ 2.5 cubic feet, more-or-less independent of the other driver.
In other words, the Velo box should work as well with two 12-inch drivers, as with one.
Now I'm doubting my own logic.
Presumably, the optimal volume for a sealed box is proportional to the subwoofer driver area. Bigger driver area requires bigger box volume.
Two like-size drivers in the same box, driven in phase, should be essentially equivalent to a single driver of twice the area. I would expect this to be true no matter where in the box the two drivers are mounted: opposite sides, or same side.
Therefore, by this logic, a box optimally sized for one driver, would be much too small for two like drivers.
(Parenthetically, I note that Rythmik's F25 sub, which uses a pair of 15-inch drivers, appears to be of roughly twice the internal volume of a Rythmik single 15-inch driver sub.)
So now, in light of this, I plan to refit my Velo ULD-15 box with a single down-firing driver. Only question is whether to go with a 15-inch DS1501 or a 12-inch DS1200. The box's gross internal volume is 2.54 cubic feet, which falls right between what Rythmik recommends for the 15-inch driver (3 cubic feet) and the 12-inch (2 cubic feet). The 15-inch would be slightly under-boxed... the consequences of which I am unsure. The 12-inch would leave a bit of extra volume for bracing (of which the very stiff Velo box currently has none). I've always thought bigger is better, but in this case I'm not sure.
I listen mostly to music, with only the occasional movie, so accuracy is more important to me than house-thumping power.
Any recommendations about which driver to put in my Velo box?