Zylon is the new material that Yamaha uses, and it sounds incredible. Same physical characteristics as Be but I think not poisonous like Be. The 12-inch woofer on the NS5000 is made of Zylon as is the tweeter and the midrange. Yes, I have this speaker.
As the previous poster mentioned, it was Yamaha that first used Be in drivers for the NS 1000 in the 1970s. That was for the tweeter and midrange. Paradigm Persona duplicated the Be tweeter and midrange about 8 years ago.