I'm not sure tapping the driver means much, is one metal and the other paper?Maybe... But all I have is the distortion measurement overlay between both speakers at the LP at 83 dB SPL which is some 9ft away:
View attachment 18348
How much is room, noise floor, and mic, I have no way of separating out. I would need to take near field measurements, and even then, the room will still be a factor at low frequencies and gating the measurement won't help. I also require a different measurement mic as their only seems to be a handful on the market that actually gives a distortion spec on the mic itself...
Also, I don't think the distortion accounts for the "size" difference. Re: tapping fingers on the cone is a dead giveaway, like I say the difference is akin to tapping on a small diameter drum (like a small tom tom) versus a floor tom or kick drum. With a couple of taps, one can identify which one "sounds" bigger...
Your chart shows much higher distortion for the 8c from it's midrange driver than I was expecting, enough to be audible. Maybe this is a cardioid penalty, with some of its output being cancelled it has to work harder for the same SPL.
I think measuring this at the LP makes sense.
Interesting stuff.
Wonder what the BXT does to the Kii in this area.