Fb is a function of Vb and Av and Lv. It is Fb and the resultant overhang (transient response) that determines the bass tuning.
Using 2 ports means the combined area of the 2 ports should equal to that one one port. since the one port has a larger area (length is the same) the airspeed in the larger port is bit slower. this means there is less chuffing in the larger port.
Av= area of vent
Lv = Lenght of vent
Fb = tuning freq of box with vent
Vb = volume of box with vent |