Hi Mark,
I understand that there's no common method to determine the 'linear motion' -- or how this the linear limit should be defined. The cited article is an interesting read indeed and helps me to get an idea. Thank you for your time and the pointer. My reasoning behind the question was to get an idea of the X_usable of your drivers, because I'm looking into a DSP solution for near nearfield use. I have read the interesting post on
http://lean-audio.blogspot.com which is very similar to my current idea (on the way to become a plan). But I'm looking into AP10 as you know instead of AP5 and just want to make sure that sound is not deteriorated when I equalize the bass and of course the driver does not break up under a "loud" bass attack. I put "loud" in quotes, because at a distance of about 70 cm to each speaker those are more like supersized headphones I guess

And last not least I only listen to moderate levels up to a somewhat higher "room loudness" and not a PA level

Best regards
Peter