Well, they have done themselves not favors with that website. That BS about cables gets them off to a bad start with me.
However it looks to be a proper TL and not a mass loaded effort, and it looks competently designed.
I did manage to find an impedance curve against frequency.
Now the bass is very extended. The important thing is that the line is properly damped. There is one peak of impedance showing the line is non resonant and shows it is aperiodically damped.
There is some loss of output from 50 to 100 Hz. The line is properly augmenting speaker output over the bandwidth of the pipe. This is what happens if you build an extended bass pipe alignment. I have not found a way round this using a single line. That is why my enclosures have two lines wound round each other tuned one half octave apart. This is a trick I learned from the late John Wright of TDL. It makes the design and build extremely complex though and demands active electronic crossovers.
I suspect however that these speakers do sound better then anything you will have heard before. That dip will probably be obscured by the room.
Speakers like this are very rare indeed. From that third party impedance measurement that speaker will have a clear and accurate bass the like of which you will not have heard before.
The frequency response across the rest of the range is exemplary. The remaining part of the impedance curve attests to very competent crossover design.
You should try and hear it before purchase.
I do know that owners lucky enough to have well designed TLs like that never can go back to ported designs for their serious listening.
