Verified answer

You should probably find a DIY subwoofer site for specifics.

Here is my understanding of things:

- A woofer moves a LOT of air out the front - but also has to have air in the back.

- Most sub enclosures have a round "port" which is horn shaped to let air move in/out of the sub enclosure. Instead of making noise - I believe the shape is designed to suppress noise because the 'chuffing' sound is NOT what you want. (Getting a high volume sub to NOT have port noise is a challenge.)

- A vent is another opening in the enclosure to let air move in/out and reduce the chuffing noise.

- Car subs often have NO ports or slots. They try to be air-tight like a drum so the pressure inside the enclosure compresses and helps the woofer move out/in. It also eliminates the port noise which would be MUCH more noticeable in the small space in a car.

Once again - search for "DIY Subwoofers" to find sites where speaker builders hang out for more details.

one has a better sound ported and vented would be my choice less chance of blowing the speaker when terned up