I have been meaning to reply in this thread, but haven't had the time, or desire really, to do so. Obviously clarification is required here.
No, it's not a matter of not liking linearity, linearity is a great thing. I don't like the idea of having to use huge gaps and a huge motor to get any sort of a decent bl or motor force out of it...(wasting materials, adding cost, generally a sub-par ideology)
If things aren't glued down, the gap has to be wider...if the coil changes density in the gap...the gap..has to be wider. (again...wasting materials, adding cost, for being able to screw a basket on and off..is not worth it)
If you can have a +/- 3dBa response from 20-90Hz in a given scenario without using 'linear motor technology' or 'xbl^2' then why wouldn't you? You get the end result that you want, which is no equalization and it plays flat..and you don't have to pay for rights of technology that is patented?
Essentially this is an argument of price vs performance. There is no way anyone can possibly argue that.
What's more important..to say that something is 100% linear on a piece of paper but on the contrary sounds horrid, or something that sounds great..doesn't need EQ'ing...and is..98% linear through the entire stroke?
Then we get into the argument of..well wait a second. What if it is the general norm of psycho-acoustics for liking peaks..liking valleys..liking distortion? Liking true LIVE music? You can put 10 different people in a room and it will be 10 different ways of perception...you'll have "sq" guys who think flat is god. You'll have horn loaded compression drivers that many think sound amazing...
If something is 100% linear on paper (and with even response) but sounds horrible, then it is the fault of the material...the music. By the way, that paper is real life, too, just so you know. Either way, I want music that sounds great, and a system that plays music (but nothing else).
Sad thing is..the vast majority of people, including myself, can't stand the sound of something that is 100% flat..it sounds dead to me, and I don't like it...
What is is about "100% flat" that you don't like? Keep in mind you have only described one characteristic of the sound's physical properties (ie. it's axial response). Also, I don't know if this is reference to the sound at the ear or measured 1m away from a driver.
So i can flop a piece of material, 100% linear, down to the micron for arguments sake.
It plays the recording accurately just and only just because it is linear and therefore an accurate reproduction of the recording? What happens when the motor peaks at 58Hz? It's still linear...but you've got a 3.9dBa peak at 58Hz? Is that because of the recording? Or is that because of the motor getting happy? (Keep in mind it is still linear)
It's not the linearity of something that matters, it's well can it play flat or not? If it plays flat from 0-20Khz then...it's linear? Or is it..un-linear? Is it the recording? Or is it the speaker?
It is important that a driver is both linear and has even response on all axis'. Further, even response is more achievable with less distortion, which is achieved with engineering that specifically targets linearity in Bl, Cms, and Le (with coil position and power, for those relevant).
It simply boils down to are you listening to the woofer paper that says it has a flat BL curve, and assuming that it yields a 100% Linear and +/- 1dB response?
Having re-read the thread, at no point did I say there is a direct correlation between BL linearity and flat axial response. I did say that there is a correlation between low HD and IMD with flat axial response; since improved BL linearity often results in decreased HD and IMD, there is a function that relates BL linearity with frequency response, but it is grossly more complex than that. Aside from the HD and IMD created by BL, Cms, and Le non-linearities, you will experience variations in response related to the alignment, the cone and surround geometry, the thermal properties of all materials, and the environment.
What the thread eventually boiled down to is another bizarre argument of "real world vs science" as if the science we are talking about does not occur in the real world. The "real world" people are aware of a handful of the things that a driver is judged with scientifically, and thus feel it necessary to deride scientific design and interpretation (or engineering, if you will) by simplifying it to "looking at BL curves on a paper". So to make sure that the usual crowd does not once again take this out of context:
1) When evaluating a driver, even response on all axis' with no distortion is preferable. The presence of distortion makes even response less likely.
2) Distortion (THD and IMD) is generated by non-linearities in BL, Cms, and Le vs coil position and current.
3) Engineering with limited distortion in mind can improve response and lower distortion. As such, any approach that targets causes of distortion should be valued.
Note: When I refer to "even response on all axis'", what I am trying to convey is even response on axis, and good polar response as well.
