Do You Have To Tune a Sealed Subwoofer Enclosure?

Everybody knows that you have to tune the port on a ported/vented enclosure to the Hz frequency you want your subwoofer to play. This is by increasing or decreasing the length of the port or the vent itself. If you are going to create or want to buy a premade sealed box, they are both not tuned to a bass frequency. A sealed box does not have a specific frequency tuning because it has no port or vent to have control of an exact bass frequency. So if you want make a sealed subwoofer enclosure play bass deeper and hit lows better, then that can be achieved by building a box with more cubic internal volume. To lower the tuning on a sealed premade subwoofer enclosure, then you would have to add polyfill inside the box. The more polyfill you add, the more low end bass response of the subwoofer is going to be heard. If you want to make a sealed subwoofer enclosure play bass louder, then that can only be achieved if you overpower the subwoofer, increasing the tuning frequency on the car amplifier, or you could simply place it in a ported/vented enclosure that is tuned to about 40-42Hz.