Relatively small speaker with a "big" performance: Role Audio Starship SE model

Yes Duke, very intriguing design. Getting a transmission line right is not easy at all. Usually it becomes trial and error. The math only gets you near the ball park. The other problem as you mentioned is the bandwidth problem. With a 6 dB/oct crossover you would have to keep the crossover high to prevent overloading the tweeter. So either you are limiting the headroom of the speaker or you are asking the woofers to run higher then perhaps they should. If this is the case then a subwoofer system crossed on the higher side will help a lot. Otherwise, this speaker should image well and certainly has enough midrange power to go convincingly loud as long as the tweeter is kept out of the action. I'm surprised they did not use a 12 dB/oct crossover. Using an active digital crossover and biamping would be a natural for this design. 

For what it's worth, I used to live in NC and paid a visit to Role about 10 years ago.  Erol was a super gracious host and we had a great time listening to music.  He is one of the Good People, and his speakers really do accomplish the Houdini disappearance act in terms of imaging.  

douglas_schroeder wrote: My reference level bass extension for a floor standing speaker is at 25Hz +/-3dB, or better.

It's interesting how such standards can vary so widely.  :)

I ask the same question about reference.

Right now, I am listening to a pair of Tyler Acoustics MM5X's built as a floor stander with 26 dbl in the bass from an 8 ohm, 88 sensitivity rating.

Good tonality, decay, dynamics, and they seem to disappear in my room with my setup (CJ preamp and CJ tube amp). 

This is from a guy who also has a pair of Thiel CS 5's and used to own Maggie 3.6s.

And I do not mean to offend anybody and have not heard the Role Audio Starship SE.   :)

The devialet phantom speakers are small enough to be held in your hand yet they can do 20hz bass. So obviously these sampan speakers are not very good considering what the phantoms can do.

Transmission lines are very impressive if we are talking cabinet volume to bass in a passive design.

If you want to go digital dsp active....holy crap, This new homepod mini will blow your mind for size to bass output.