In the creation of the diaphragm for the Norn IEMs, extensive research and tests were done to find the perfect material to make up the diaphragm. The choice ended up being a titanium-plated polyurethane composite high-poly fiber suspension diaphragm.
This mixture of materials allows the diaphragm to have numerous properties. The high-poly fiber allows for rigidity of the entire diaphragm, which produces uniform sound with its vibrations as well as durability for its structure.
At the same time, the polyurethane gives flexibility to the diaphragm, which allows it to dive to an extent that produces deep bass notes.
The titanium plating provides rigidity, similar to the high poly fiber, but it adds a quality to the audio of its own.