Metal speakers. How are they?


I notice that aluminum and magnesium cones have become very common, including in some high quality systems. What's the story on these things? I am considering purchase of a speaker that has Seas 7-inch magnesium woofers, in MTM configuration.

These speakers will replace Dynaudio Gemini MTM speakers whose little 5" woofers are great, but just won't keep up with my three MG1.6 + SW front speakers. I have contemplated rear subwoofers, but there just is not space. The Dynaudios were used for many years as the high end of a biamped system, and they were fine for that purpose.
eldartford
I generally love speakers designed with the SEAS drivers even though I haven't been able to listen to all of them. They generally produce pristine sound that is quite beguiling and musical (live feel: piano sounds exceptionally good). According to one of the replies to my post, the SEAS drivers are hard to design with and one needs to choose the brand carefully.
Materials don't (shouldn't) matter. At an introductory seminar (Rosine Audio -Skokie, IL), Arnie Nudell (founder of Infinity and Genesis speakers) was asked if diamond coated drivers would sound good replied: "Drivers made of horse-shit would sound good if they were linear in their frequency range"...
I respectfully submit that materials DO matter. Metal cones can and do ring and have harsher break-up than (conventional) treated paper. This said, there are excellent metal performers -- the "21" Seas are amongst the best. Best,