Frequency response of planar diaphragms/membranes

[solhaga]

I'm on the verge of making a diaphragm for a bass planar.
The diaphragm can be as large as 700x700 mm with a push pull driver section of 500x500 mm in the middle; suspension is then 100 mm wide. Xmax is +/- 9 mm.

Wanted frequency range is 20 Hz to 400 Hz as it is a two way system with a AMT with a CD wave guide that I currently XO at 350 Hz.

So what to aim for?

A light weight diaphragm with possible break up problems or a heavy weight one having the traditional TS parameters in mind?

 

[solhaga]

Here's as interesting patent: Planar diaphragm loudspeakers with non-uniform air resistive loading for low frequency modal control.

In the introduction it says:

The mechanical properties of thin film or non-rigid diaphragm loudspeakers are such that, at high frequencies, air mass controls the high frequency operation and the mechanical stiffness of the diaphragms controls the lowest frequency performance of the loudspeakers.

The patent is about, AFAIK, not to make a light weight diaphragm more mechanical stiff but to make it more resilient to standing waves for frequencies that have fundamental wavelengths within the geometry of the diaphragm by using carefully calculated openings in the stator plate.

plurality of non-uniformly spaced openings is flared outwardly both toward an inner surface of said at least one stator plate and an external surface of said at least one stator plate.

The magnets are mounted on the stator plate but there seems to be more "surfaces" until the sound hits free air.

Comments?
Anyone know if there's a commercial product based on this principle?
(Google just keeps bouncing back to the patent, seems to be think tank for patent in this domain)