01 01 Scan-Speak manufactures speakers with copper in the magnet system. The original Symmetric Drive patent by Ragnar Lian ran out around 1993 and a new design was patented to replace the original. This design is named SD-1 and entails 3 copper rings in the magnet system, two located on the pole piece near the air gap, see picture (1), and a third ring near the bottom plate. World patent 1994027413 A1, valid from 1993 - 2013.
1990s; because it combines the best qualities of the aluminium former (stiffness) with low electrical conductivity (so you don’t get undesirable electromagnetic damping) and it can be made even thinner than aluminium. It also has low heat conductivity, which you can see as either a positive or a negative feature. According to my source, the earliest requests for such former material came from Ingvar Öhman (a Swede) and Vifa forwarded this request to their suppliers.
28 — The Danish loudspeaker 100 year anniversary
The suppliers became tired of the repeated requests and eventually they started to offer this option. New horizons In 1987 Skaaning was forced to leave Dynaudio. In 1990 Skaaning founded a new company, Audio Technology. This was the 5th loudspeaker company founded by Ejvind Skaaning, and the last one – co-founded with his son, Per Skaaning, who