I really like TL speakers. They have much tighter bass in general than a ported speaker, which can sound boomy in comparison. Ported speakers essentially act as spring resonators to enhance bass, and therefore that resonance tends to muddy out the bass. In a good design, this can be hard to notice, but a TL will always have tight bass if designed right. Although this mightgive the impression of LESS bass, because of the lack of resonance.
The reason TL's are not very popular is because they are much harder to make in a production sense than "six sides and a port". They also require more volume to make the line, and require a lot of stuffing with natural wool being the best material by far. Not very practical in a money-making operation, but very reasonable for a DIY project.
If you come to Portland, I have a DIY transmission line speaker which you might want to hear. It uses the Jordan full range 4" driver.
