Okay, lemme try to explain this and maybe some of you will get a better idea of why I got upset in the first place. We were talking about maximum Sound Pressure Level (SPL) that a mic can handle. That's pretty simple to test.
Hook the mic up to a distortion meter, crank a known source till the output hits a certain percentage of distortion (usually 1/2% or 1%, depending on the manufacturer). When it hits that percentage, stop and measure the actual SPL being produced by the source, and that's the "MAX SPL". Pretty simple, huh?
The question remains: exactly what is it that's distorting? The answer is: Who cares? That's the MAX SPL, unless you wanna go in there and change something.
It could be the diaphragm bottoming out, it could be the diaphragm tensioning, not enough polarizing voltage, or the air space, or even the preamp crapping out, but it doesn't make any difference - you live with the max SPL figure unless you wanna make some changes in the design. It's the sum of all the things you've done when designing the mic.
If you wanna redesign things, then yes, you can improve the max SPL, depending on what is distorting. For example, if the pre-amp is clipping and the capsule isn't, you can put in a 10dB pad which will increase the SPL rating accordingly. If the capsule is crapping out, you're gonna hafta redesign it.
But when you're getting up into 135 to 145 dB SPLs, a piece of film about 1/3rd the thickness of a human hair isn't gonna do a whole lot better than a piece of film 1/6th the thickness of a human hair in handling more SPL. It just isn't one of the big factors.
Stephen Paul is THE expert in thin films of 3 microns and below - he did it first, and he still does it best. AT could be having some problems in getting the tensioning right, but any increases in max SPL are not related to the diaphragm thickness - it's just not a big factor when it comes to increasing the max SPL handling.
If you're designing a condenser mic and you wanna increase the max SPL rating, you won't ever see a bunch of guys sitting around a table saying, "Let's make a thicker diaphragm to get a little more SPL handling.", anymore than you'd see a bunch of guys trying to design a faster car by sitting around a table saying, "Let's put in a back seat to make it go faster."
Just like a car, weight isn't a factor in deciding how to increase the top speed. Adding more weight doesn't make the car go faster. You increase the engine size, or the max RPM, or change the gear ratios, or change the tire size, or make the body more aerodynamic to increase top speed. And going to a heavier car body will not make the car go faster.
Stephen can build a 0.6 micron diaphragm that will handle just as much sound pressure as a 6 micron diaphragm - a full one magnitude difference in thickness. If he then switched to a 6 micron diaphragm, the max SPL handling would NOT go up.
MAX SPL is whatever it is - after the mic is finished. If you want a higher max SPL, you hafta go in, see what's limiting the max SPL, and change it, by redesign.
MAX SPL is a measurement of the mic's performance; it's not a fault to be fixed - it's a real world measurement of one aspect of the mic's performance.