Is Apogee in a class by itself among planars?

Trelja...How do you create a strong magnetic field across the gap of a wide ribbon? Can you please describe how the magnetics of the Apogee are set up.

I have always argued my bass panel consists of a softly held zig zaging ribbon. It's a bit more complicated than that. Large bar magnets are densely arranged in horizontal rows, and are attached to a metal grid just behind the Mylar/aluminum ribbons.

Eldartford...from the Apogee forum regarding the Apogee magnet layout:

"Apogee bass panels are single-ended...(Magnets on one side only) As the panel moves backward toward the magnets,
the magnetic field gets stronger. As the panel moves away from the magnets - the magnetic field gets weaker. Therefore, there is an asymmetry to the reproduction of the compression waves vs. the rarefactions.

If the panels had TWO sets of magnets; one in front and one in back - then there would be
no asymmetry. As the panel moved away from the back magnets - it would be moving closer to the front magnets and visa-versa. There would be no asymmetry in the production of the compression waves vs. the rarefactions."

"The classic or "true" ribbon like the Apogee MRTs is "double-ended". There are magnets
on both sides - left and right - of the MRT and as the ribbon moves forward and backwards
there is no asymmetry in the magnetic field that the ribbon experiences.

In essence, the MRT ribbons look / work the same if you turned them around front to back.
Thats not the case with a single-ended driver like the Apogee woofers. The compression /
rarefaction asymmetry changes if you flip them around"

"the trapezoidal shape is for control of resonances or vibration "modes"
Because of the shape - the width of the ribbon is not constant with height.
Therefore, the resonant frequency is not constant with height. So resonances are "spread out".

Dave

i have not heard the analysis plus or the quads. i have heard the duetta sigs powered by a huge rowland from a good dac. i wsh the systems i heard at the last two rocky moutain audiofests sounded as good as this kit, but they didn't. i could hear the amp, which was very good. the speakrs were not the limitation of this system. best i've heard, by alot.

Muralman1...This sounds the same as Maggies, except the magnets run in horizontal rows instead of vertical rows.

Sogood51...Having magnets only on one side (front or back)of the panel does theoretically give an asymmetrical drive, but, because the panel excursion is so small this effect is also small. Also, keeping excursion small by using a subwoofer minimizes the asymmetrical drive situation. This would logically improve midrange performance...more so than with a cone driver where assymetrical drive is not an issue.

As I understand it (correct me if I am wrong) the magnets of a ribbon are located IN THE PLANE of the ribbon, to the left and right. This only is possible if the ribbon is narrow.