A web site with DIY and commercial audio products
I'm a member of this organization, join if audio is your passion
Siegfried Linkwitz, well known of the Linkwitz-Riley family of cross-over filters
for non-coincident drivers has his own web pages
Find anything on EU's radio standards
Europeans try to regulate everything up to the curvature of cucumbers
The telecom regulations can be found here.
low power radio as an association