2013 Advent Calendar Day 23

The aka c414 This microphone has been released and re-released over the years because it is such a great workhorse. It has four switchable polar patterns (cardiod, hypercardiod, figure of eight, and omni), a 0-10-20db selectable pad, and a 0-75-150Hz low end rolloff filter.

2013 Advent Calendar Day 20

The U 47 was the first microphone with a switchable pick-up pattern. By manipulating the polarization voltage on the rear diaphragm the mic can achieve either a “cardiod” or an “omni” pattern. A nearly identical microphone was also made, the U 48, whose only difference was a different method of Read more…

2013 Advent Calendar Day 12

Astatic 600 “Conneaut” microphone This streamlined, rocket age 1946 design was named after the town where Astatic was headquartered (Conneaut Ohio). It was made in 2 versions, one with a chrome grille (pictured) and another with an elaborate molded plastic grille in the shape of a jet engine air intake.

2013 Advent Calendar Day 8

RCA 6226 Aeropessure Type microphone The “Aeropressure” was a rugged radio announcing and public address microphone designed for on-location use, featuring exceptional wind noise suppression. During its some five decades of microphone production, probably no other single manufacturer came close to the technical engineering expertise, development innovation, and product line Read more…

2013 Advent Calendar Day 5

RCA Ribbon Microphone In the early 1920s, Drs. Walter H. Schottky and Erwin Gerlach co-invented the first ribbon microphone. A few years later, Dr. Harry F. Olson of RCA started developing ribbon microphones using field coils and permanent magnets. The RCA Photophone Type PB-31 was commercially manufactured in 1931 greatly Read more…

2013 Advent Calendar Day 3

Blake Transmitter In 1877 Francis Blake invented a carbon microphone for use in the telephone, shortly after Thomas Edison invented a microphone that also used carbon contacts. Blake used a carbon button design that initially would not stay in adjustment, but with later improvements proved to be workable. Alexander Bell Read more…

2013 Advent Calendar Day 2

Bell’s Double Pole Membrane Transmitter. Bell’s Double Pole Membrane Transmitter and Iron Box Receiver were used in 1876 to transmit and receive the world’s first one-way long distance telephone call from Brantford to Paris, Ontario. Canada’s first two-way long distance telephone conversation was between Montreal and Quebec in 1877.

2013 Advent Calendar Day 1

This year I am going to make an advent calendar using my blog. It will be featuring cool or historically important microphones. This is Bell’s original liquid transmitter from a set of Bell Laboratories photographs in the Ron Christianson Telephone Collection.