Reference number
  • LAN/6/225
Alternative reference number
  • 1929-318279
Level
  • Item
Date
  • 01 Jun 1928
Description
  • Moving coil microphones intended to pick up sounds for subsequent amplification, especially for music; pickup and discharge of the sound are made with the minimum of obstruction between the two parts of the microphone. Later application 1 November 1928, complete left 1 April 1929.