Compact subwoofers are ether sealed or have passive radiators.
Ported Subs are typically bigger in size - more power efficient and have lower bass extension, but typically less accurate than sealed models.
I'll personally pick properly designed ported sub vs sealed every time as compact size is not priority for me...
Passive rads subs are somewhere in between these two - getting most of benefits from both, yet cost more than both.
These are not only types of subs - there bunch of others like Dual Opposed, Servo, Folded Horn etc...
