Gobel and the Bending Wave

The Linaeum tweeter is a flexible membrane and is excited at the center with the sound wave emitting off the surface as the wave travels from the center to the edge.

Right, and if that is accurate, the Linaeum would be a bending wave device but by contrast, AMT’s are excited across the length of each pleat simultaneously. I found this article which was interesting and included more on the subject:

http://www.soundimage.dk/Different-col/Bending.htm

AMTs are conspicuously absent.


I think the only similarity is really in that pleat. Lineaum uses a single pleat as the motor, AMT’s use multiple pleats. AMTs work not by moving back and forth towards the users, but by squeezing air in and out from between the pleats, more like an accordion.

More here:

https://en.wikipedia.org/wiki/Air_Motion_Transformer

And here:
https://www.audioholics.com/bookshelf-speaker-reviews/monoprice-monolith

But there’s no description for an AMT I’ve ever read where one area of the membrane is excited at one location, and then a wave is transmitted on the surface. Instead, each pleat is like a ribbon’s conductor in a magnetic field.

Ah. I had thought that the Linaeum AMT was also the Linaeum bending wave tweeter, but apparently they are different. You can see the Lineaum bending wave tweeter in the first link you provided above.

@atmasphere -

I'm not a Linaeum historian, the only tweeter I know them from was the butt-cheek like driver made famous by Radio Shack.


If they also made an AMT that would be news to me. Let me know if you find a link to one.


Best,
E

Erik, I have a pair of that Radio Shack speaker, named the Optimus Pro LX5. The Linaeum driver was used as a dipole in that model, and as a direct radiator in an even cheaper model.

Hey bdp24

This is staring to sound familiar. Honestly, I'm more than a little surprised that this tweeter design didn't last well into the late 20th and early 21st century. I don't remember hearing it, but it's' innovative design should have made it a long lived classic.


Best,

E