Dear Raul, That’s a very interesting article. The author makes a good point that using the term "fast" when describing a woofer is specious, because the "speed" required to reproduce very low frequencies accurately is within reach of any well designed woofer. But then he goes on to say: "There are reasons to use lighter, lower-mass woofer cones. They just happen to be different reasons than the ones you’ve read in print. Smaller woofers don’t make faster bass, but they do reproduce higher frequencies than larger woofers can reproduce, and this is all important when it comes to speaker design. You want the midrange driver and the woofer to integrate with sublime symmetry, with perfection and with nary a single problematic interaction throughout their overlap zone. This is why you want smaller, lighter, "faster" woofer cones -- not because they lead to faster bass. That overlap zone is so amazingly critical to your perception of bass speed that there is little or no tolerance for error." Note also that your expert does allow for the idea that some woofers are "faster" than others; he has only re-defined the term in a sense with which I do not disagree. By the way, no one "told me" anything about this. My conclusions are based on real world experiences that I had maybe 35-40 years ago when I was playing around with woofers to supplement ESLs that I then owned. So, I am expressing my personal independently arrived at opinion.
So perhaps I can be faulted for my choice of the word "fast", but what your authority wrote above is what I had in mind. Now if Mijostyn is using an 80db/octave crossover, on both high and low pass filters, then perhaps the capacity of his woofers in his system to produce higher frequencies is moot. On the other hand, all of his audio is passing through the digital domain afforded by his digital filter. That does not appeal to me.
Mijostyn, Along the same line of reasoning, you wrote, "Lastly, there is no such thing as a "fast subwoofer" when a woofer is not fast enough it’s high frequencies roll off." I hope you see the internal contradiction there. If there is no such thing as a fast woofer, then there is no such thing as a woofer that is not fast enough. But to both you and Raul, I would concede that I was guilty of sloppy semantics. When I say "fast woofer", I am thinking of the woofer and its enclosure as a whole. And I did not make that clear. You could put a small, i.e, "fast", woofer in an enclosure that limited its speed by virtue of what happens to the back wave, and it wouldn’t sound so fast, which we can define here as able to integrate well with an ESL panel. Like I responded to Raul, perhaps with an 80db/octave slope you need not worry about the capacity of your woofer enclosures to deal with frequencies above your crossover chosen point.