hi, i have often heard that when you put multiple subs in a ported chamber then you need to double the volume of the box for each extra sub. say if one sub needs 1.5 in ported to opperate then two would need 3. they are in the same air space. and i have also heard that no extra is needed. also have heard that just add for the displacement of the subs. for air space. for ports i have heard about the same thing. two subs need two ports. two subs needs one port double in size for one sub. can someone help me on this. what i want to know and do is run two 12's in a ported box with shared air space. the sub requires 1.25 to 1.75 for ported and a 3"x7.5" round port. i want two in this box. please advise
james.
james.