Indeed. Their graphs which show that their driver is linear, whereas a conventional driver isn't, don't have any corroborating evidence for that. We know and it's well understood that loudspeakers compress at high levels, in part due to thermal effects and in part due to suspension non-linearity as it runs out of excursion. However, I've never seen any suggestion that a loudspeaker is non-linear at low levels. It sounds like they're suggesting the loudspeaker is 'sticky', like limiting friction, that stops it moving until a certain minimum force is applied.
If that were true, then it would affect microphones as well, which in the case of dynamic microphones, are just like loudspeakers in reverse. Again,not anything I've ever seen suggested in Pro circles.
S.
They are referring to Klippel, who's written quite a lot about distortion and linearity in loudspeakers:
https://www.klippel.de/fileadmin/_m...linearities–Causes_Parameters_Symptoms_01.pdf
I read that paper some while back, and understood less than half of it. I do have a sense that there's some sound reasoning behind their design though, even though they are audiophiling it up by adding flowery language. My layman understanding is that it is indeed higher amplitudes which causes most problems for loudspeaker drivers. But I don't think this is only a problem for what we think of as "loud" levels, because music contains transient peaks which can be much louder than the continuous tones. There is also very little published research into dynamics and trasients when it comes to sound reproduction in the home.
I also have a sense that this is a real problem, because there are several manufacturers I regard as firmly placed in the the no bullshit camp who are concerned with the linearity of loudspeaker drivers. Dutch & Dutch apparently chose drivers for their 8C speaker out of considerations about "pistonic" movement, in order to achieve a smooth and linear reproduction of the signal. Their main engineer had this to say about their driver selection over at gearslutz:
"Let's first consider drivers in terms of achieving flat and smooth response. In order to achieve maximally flat and smooth response, you need drivers that are pistonic in their passbands, with no resonances. Size in itself is not relevant. In passive loudspeakers non-rigid but well-damped drivers make sense, because they are generally easier to deal with in the crossover. Pistonic, resonance-free drivers ultimately offer greater clarity and in a DSP-based system their out-of-band quirks are easily dealt with".
And I received this email from M. Kravchenko, a manufacturer who makes loudspeaker drivers for different companies. He explained to me why he had designed a new woofer for the Morrison omnis:
"The existing woofer is a pretty good driver so it is not to easy to improve upon. What I did was change the motor from XBL to a complete underhung system. The XBL motor is kind of a a solution looking for a problem. Specifically it trades efficiency for a flatter BL motor force curve. It was a clever way around the truly great engineering feat of a split coil motor patented by B&C loudspeakers. Clever in a sort of should we have done it way? It is a complicated way to trade off different strengths and weaknesses in a loudspeaker motor. It also introduces more tha nit's share of potential problems. The top part of the motor movement is not as strong as the bottom part as a simple example. The motor parts are more expensive to make and they also add in a break in the magnetic circuit right where you do not want one. So I changed the design to underhung. Solved quite a few problems. "
I'm not going to claim that I understand what all this means. But my take-away is that there are trade-offs in how different drivers work.