Early slack diaphragm condenser microphone, with p
Early slack diaphragm condenser microphone designed by P G A H Voigt, with plug (wall type) (pat. No. 263,300 of 1924-5)
Early slack diaphragm condenser microphone designed by P G A H Voigt, with plug (wall type) (pat. No. 263,300 of 1924-5)