This is a great post. I learned so much about this and similar designs today that provide direction of my next speaker upgrade. Thanks for bringing TL design to the forum and thanks to all those that contributed to the discussion.
My current speaker set uses a loose concept of the TL design but I was unaware of how the construction is classified and incorrectly thought I had stumbled across a unique design. I am enamored with this low frequency sound and today have found the path to take when upgrading. Thanks again!