THD Podcast 7 - Air Motion Transformer (AMT) Drivers With Application in Near Field Speakers 

I'll be the 1st to admit David and Simon are polished. I'll improve.

AMT are great devices. Oscar Heil, who also invented the F.E.T. had studied the larynx & vocal chord shape & arrangement of the common Frog to construct the fundamental design of his Air Motion Transformer. The AMT's sound is squeezed out by the undulating compressions of the folded diaphragm with less physical movement.. (& hence less energy so at a higher efficiency) ...& at a higher velocity & than the pistonic motions of any standard woofer /mid / tweeter cones or flat ribbon / electrostatic mid-tweeter panel. Directivity is introduced in any speaker when the reproduced frequency is narrower than the driver or panel making the sound. 10"inch woofers "beam" above 1,100 Hz. A 2"inch driver beams above 2,300 Hz. A graph of frequency & wavelengh on the A & B axis, will tell you above what frequency any driver or panel will start to beam it's sound, useful for designing in sound distribution by selective x/over points & driver size.

Should AMT be in all studio monitors, are there any use cases where soft dome tweeters may be preferred or better

Worst quality I have ever seen terrible