How come the Hsu VTF-3 isn't included in the list that 2x6 just linked?
It's more popular than most others listed there...
With regard to the port clearance, I wouldn't underestimate the importance of a good clearance: When my VTF-3 (max extension mode, with one port open) is working hard to reproduce bass sound close to the port-resonance frequency at ~16Hz, the air velocity at the outer end of the port is just ENORMOUS. I can feel lots of "wind" blowing onto my palm even at 3-4 feet away from the port. While I don't think 3' clearance is a must, I tend to feel that "the more the better."
