I always see the Vented vs. Sealed argument come up a lot and I understand the differences and pros and cons of each. What I cannot seem to find something that details why I would want to use a Passive Radiator or a Transmission Line or even a 4th Order Bandpass box. I have just been curious about the advantages/disadvantages and unique qualities of each. Also why I would potentially want one of these box types over a basic vented or sealed enclosure.