Suppose you have some speakers that contain a woofer and a tweeter in one box, but you don't know anything about the drivers (fs, Qts, Vas, etc). Assuming the box volume has originally been calculated correctly using the values of the drivers, is it possible to calculate the volumes for each individual speaker to be in separate boxes? A naive approach might be to take the ratio of the diameters of the drivers and split the volume by that ratio. What approach could be taken?
The box volume has been calculated for the woofer. The woofer will need the same volume after repackaging. The tweeter has more volume than it needs: the original design does not tell you how much it will need. It's unlikely you'll pick too small a size, though. Quite a few tweeters are even already closed in the back.