Antistrange.
You might want to check out this link.
http://www.classicspeakerpages.net/dc/dcboard.php?az=show_topics&forum=5
The guys there are really into the old "New England" sounding speakers such as Advents, EPI, AR, ect and could probably answer your questions about your Advents "fried egg tweeter" and how to get better high frequency extention out of them.
Good luck in your quest.
You might want to check out this link.
http://www.classicspeakerpages.net/dc/dcboard.php?az=show_topics&forum=5
The guys there are really into the old "New England" sounding speakers such as Advents, EPI, AR, ect and could probably answer your questions about your Advents "fried egg tweeter" and how to get better high frequency extention out of them.
Good luck in your quest.