I will add once more the statement made in an earlier Post.
A Transmission Line design for the Cabinet will produce a improved structure to the Bass presence.
A TL is also able to substantially reduce residual Bass energy where the Bass generated is more ESL Speaker than Cabinet Speaker.
The Tunnel when designed correctly has the capability to absorb Bass Radiation preventing Upper Bass frequencies transferring into the Midrange and Upper frequencies, resulting in the masking these frequencies presence.
The Tunnel also has an impact where the Tunnel increases the extension of the Bass frequency, where it can mimic Bass produced from a Driver with a substantially increased surface area.
FWIW, I recently learned about a Speaker Builder who's work I been able to experience in use across many years, where I have been thoroughly impressed and Inspired, is now a using a main Speaker that is a Transmission Line produced by a Company known for their DIY TL Designs.
Interestingly as well, the same individual prior to this most recent TL Speaker was using a 10" version of Single Driver TL Design that I am now using as a 12" Single Driver TL Design. These Speakers were built by a very successful Cottage Industry Speaker Company, who's support with other areas of design, is carried out by an individual who freelances and has been the producer of Speaker Designs for a few Companies with a Global Wide exposure in the Speaker Market.
I am struggling to find fault with the 12" TL Design I am using, and auditions of these in use to others, has enabled them to win further favour from those who are new to them in use, especially when being driven by a 5 Watt Output SE 300B Amp.
I can only explain how experiences had, have created a positive impression on myself, and if possible, share where experiences had by others of the same set up, have also been a reported on as being positive as the outcome.