Sonab speakers were well researched in their design. Read about them and their designer, Stig Carlsson, here.
http://www.carlssonplanet.com/index.php?PHPSESSID=10571310094a7e07d0cbf02dd8bb9f14
http://www.carlssonplanet.com/index.php?PHPSESSID=10571310094a7e07d0cbf02dd8bb9f14