The EEVBlog has been featuring segments on microphones featuring Doug Ford, formerly of Rode.
Intro to Microphones:
http://www.eevblog.com/2014/04/12/eevblog-602-introduction-to-microphones/
Figure 8 and Cardioid microphones:
http://www.eevblog.com/2014/04/20/eevblog-605-fig-8-cardioid-microphone-patterns/
Condenser and Electret Construction:
http://www.eevblog.com/2014/04/26/eevblog-608-condenser-electret-microphone-construction/
Intro to Microphones:
http://www.eevblog.com/2014/04/12/eevblog-602-introduction-to-microphones/
Figure 8 and Cardioid microphones:
http://www.eevblog.com/2014/04/20/eevblog-605-fig-8-cardioid-microphone-patterns/
Condenser and Electret Construction:
http://www.eevblog.com/2014/04/26/eevblog-608-condenser-electret-microphone-construction/