The VTF series subwoofers are the most adjustable subwoofers in the world. It's like buying 10 or more different subs for the price of one. For a given budget, you can design it to go low, or play loud, or have a ported subwoofer or sealed subwoofer, tight bass or full bass, but not all at the same time. Now with the VTF series, you can have any possible combination. You can operate it in one port open, two ports open, or sealed mode. You can adjust the bass tightness by using our Q control. Whatever your preference and room acoustics, you should be able to find a setting that works great for you.