Quote Originally Posted by robertbartsch View Post
...Altec alumium drivers typically do roll off considerably above 10K...
You're confusing material with size. Altec large format and small format diaphragms are made from exactly the same aluminum alloy, yet exhibit quite different performance bandwidths.

I find it interesting that with the exception of implantable hearing aids, where titanium has a signifigant biocompatibility edge, titanium has been of little use in microphone xdcrs.