Looking for input: Best material for mid range cone


I had a surprise last night when I switched speakers in my system.  I've got a few pairs, but had been listening mainly to some Ascend Sierra 1, which have a polypropylene cone with a soft dome tweeter in a bookshelf design.  Anyway, I've got a pair of Tannoy Precision 6.1's, and swapped them in.  

The sound was noticeably different.  Piano sounded better, vocals had a finer quality as well, and the whole sound seemed a little more lively.  Now the Tannoys have silver interior wiring, a titanium tweeter in a coax design and are only rated for 75 watts. The cone material is some kind of pressed paper fibre.  And they are voiced to somewhat push the midrange.  But the sound was compelling.

I'm just wondering about cone material because some old Paradigms with Polypropylene were really not up to snuff, but they were quite old.  Any thoughts?
213runnin
Paper absorbs humidity and it changes sound accordingly.  If coated that changes it all. That said, Youtube Vandersteen showing his carbon fiber cones vs a WELL KNOWN paper cone that's used in speakers from 15k to over 100k.  It shows the paper cone being out of phase quickly and that creates smearing.  No crossover can compensate for this.  
I prefer paper, polymer, mylar, wood, ceramic, woven fiber of various sorts, and metal. Oh, yeah, and diamond.  


Driver material is only one part of the equation in a speaker. 
Paradigm uses Beryllium in our Flagship Persona Series Speakers.  Here's a couple of great, in depth videos about it.

https://www.youtube.com/watch?v=5FXTLFOJlxg

https://www.youtube.com/watch?v=Nv6wK2XenAc

Again, it's only one piece of the puzzle.  You have to mate that material to a motor system, the motor system has to be controlled by a crossover, and all of that has to be put into a great environment for it all to work.  It's always a sum of all the parts, not just a part, that makes the instrument, or in this case the speaker, sound magnificent or not. 

Here's another intuitive video talking more about all those other parts. 

https://www.youtube.com/watch?v=Q9cFZk-GhLw

These are nice short 5 minute'ish videos.  

Thanks for watching!
There is a great article on this topic over at Audioholics:

https://www.audioholics.com/loudspeaker-design/loudspeaker-drivers/diaphragm-material

I have 4 speaker in my lineup and offer and us an aluminum driver, two different magnesium drivers and a paper driver.  Three of my tweeters are soft domes and one is a ceramic and magnesium sandwich.  

What is best?  Highly debatable.  I happen to really like the sound magnesium drivers produce and happen to like ceramic drivers.  Never been a particular fan of beryllium despite it's technical superiority. 

It really is a matter of taste.