Jack Mullin: Man of Sound
How It Works
Magnetic tape recording uses electromagnetic induction to convert an electrical audio signal, or a voltage, into magnetism which is used to align magnetic particles on a recording tape reel, which creates a magnetic representation of the sound. To play the recording back, you have to do the reverse. A magnetic signal from the tape is converted back into electrical waveforms which is sent to an audio console. The audio signal is sent to the tape recorder where it's put into the record head. This is a temporary magnet that converts the incoming sound into lines of magnetic force, or flux. The tape is pulled past the record head which forms at the gaps of the magnet. This magnetic field aligns the particles on the tape to create the sound.
Peter Hammar, from Mix Magazine can give us information about this.
"Mullin’s Crosby Video prototypes established engineering principles that became the basis for many professional and consumer audio and data recorders, including the closed-loop capstan that later appeared with great success on 3M’s Mincom line of data and professional audio machines, on Ampex data recorders and in many consumer decks. Mullin’s Crosby Video machine also spurred Ampex, RCA and the BBC to begin their video development work. Ampex won that race in April 1956 with the world’s first practical VTR, the Ampex VR-1000 (the secret was the use of spinning heads past slow-moving 2-inch-wide tape), as well as vestigial-sideband FM recording." - Peter Hammar, Mix Magazine- 1999
Courtesy of American Engineering Society
