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
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Stiff and light with breakup significantly out of the crossover frequency 

simple really

till you try try and build it.

look at energy storage and pistonic motion IF you are not a science denier...
I became a planar guy after I purchased the Martin-Logan Aeon 12 years ago.  Since then, I have owned Magnepan 1.7 and Quad ESLs (I think the model was 2805) .  I still have the Maggies, but I am not using them.  A few months back I purchased a pair of Kipod 2 speakers used at a very nice price.  The Kipod speakers use aluminum speakers machined from blllets of solid aluminum for the midrange and woofer.  While they are very expensive if purchased new, you can expect to pay 25% of the  new cost for a good used pair.  These speakers are incredible in the midrange and the soundstage, tone, etc. are spectacular.  I prefer the sound of the Kipods over any speaker I have ever heard.  Save your pennies and look for a good pair of used Kipods or other YG speakers with aluminum drivers. 
@russ751,

How can the Kipods be any good when made of such an antiquated material? Don't you know that good speaker drivers require super exotic composite materials, the more exotic the better......😂