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Physics 1251 The Science and Technology of Musical Sound. Unit 4 Session 38 MWF Analog Recording and Playback. Physics 1251 Unit 4 Session 38 Analog Recording. Who is Robert Moog and why is he important?. Robert Moog (rhymes with vogue) invented the Moog Synthesizer, a
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Physics 1251The Science and Technology of Musical Sound Unit 4 Session 38 MWF Analog Recording and Playback
Physics 1251 Unit 4 Session 38 Analog Recording Who is Robert Moog and why is he important? Robert Moog (rhymes with vogue) invented the Moog Synthesizer, a pioneering instrument in the development of the synthesizer.
Physics 1251 Unit 4 Session 38 Analog Recording 1′ Lecture: • Recording requires a transducer, such as a microphone, to produce an electrical signal. • Common types of microphones are (1) condenser; (2) magnetic; (3) dynamic; (4) ribbon; (5) piezoelectric; (6) carbon. • Recording also requires amplification as well as a storage medium. • Analog recording media include vinyl record, magnetic tape, magnetic disk and optical film. • Playback uses physical principles in which mechanical oscillations, magnetic domains and optical density variations produce electrical signals that are analogous to the recorded sound.
N S Physics 1251 Unit 4 Session 38 Analog Recording 80/20An electric guitar uses a magnetic pickup that produces an electrical signal by a time-varying magnetic field. Steel Guitar String Pickup
N S Physics 1251 Unit 4 Session 38 Analog Recording 80/20The Faraday Effect : a magnetic field that varies in time produces a voltage and current in a coil. Current
+ + + + + + + + + + + + Physics 1251 Unit 4 Session 38 Analog Recording 80/20A Condenser Microphone uses electric induction to produce an electrical signal. Charge = V (εo S/x) Voltage V Current I
Physics 1251 Unit 4 Session 38 Analog Recording 80/20Magnetic Microphone: a small magnet, attached to a moving diaphragm induces a voltage and current in a coil. Current I Voltage V
Current I Voltage V Physics 1251 Unit 4 Session 38 Analog Recording 80/20Dynamic Microphone: a diaphragm moves a small coil in a magnetic field inducing a voltage and current. N S N
Current I Voltage V Physics 1251 Unit 4 Session 38 Analog Recording 80/20A Ribbon Microphone uses a light weight ribbon of metal moving in a magnetic field to produce electrical signals. N S
- - - + + + + + + + + + Physics 1251 Unit 4 Session 38 Analog Recording 80/20Piezoelectric Microphone: a thin crystal is bent which produces a small voltage. Voltage V
Physics 1251 Unit 4 Session 38 Analog Recording 80/20Carbon Microphone: a diaphragm compresses a sealed container of carbon granules, changing its resistance. Current I I = V/R Voltage V
Physics 1251 Unit 4 Session 38 Analog Recording Microphones: • Electrostatic—Induction • Condenser • Magnetic—Faraday Effect • Magnetic • Dynamic • Ribbon • Piezoelectric—Piezoelectric Effect • Carbon—Ohm’s Law
Physics 1251 Unit 4 Session 38 Analog Recording 80/20A Vacuum Tube is an electronic device that amplifies electrical signals by permitting a small voltage to modulate a much larger current. Cathode Vin Vout Grid Plate Gain = Vout /Vin
Physics 1251 Unit 4 Session 38 Analog Recording Amplification: Gain G = Vout / Vin Vout = G Vin Vout Vin
Physics 1251 Unit 4 Session 38 Analog Recording 80/20A Field Effect Transistor (FET) is a solid state electronic device that permits amplification of electrical signals. Gate Source Drain Silicon Dioxide Silicon
Physics 1251 Unit 4 Session 38 Analog Recording Analog Recording Media: • Mechanical • Edison’s Phonograph • Vinyl LP Records • Magnetic • Magnetic Tape • Magnetic Disk • Optical • Audio Track on motion picture film
Physics 1251 Unit 4 Session 38 Analog Recording Mechanical: • Edison’s Phonograph
Physics 1251 Unit 4 Session 38 Analog Recording Mechanical: • Edison’s Phonograph • Vinyl LP Records
Physics 1251 Unit 4 Session 38 Analog Recording Analog Recording Media: • Magnetic • Magnetic Tape • Magnetic Disk
Physics 1251 Unit 4 Session 38 Analog Recording Analog Recording Media: • Magnetic • Magnetic Tape • Magnetic Disk Ferro-metal Oxide Tracks
Physics 1251 Unit 4 Session 38 Analog Recording Analog Recording Media: • Optical • Audio Track on motion picture film Stereo Audio Tracks
Physics 1251 Unit 4 Session 38 Analog Recording Analog Recording Media: • Optical • Audio Track on motion picture film Stereo Audio Tracks
Physics 1251 Unit 4 Session 38 Analog Recording Summary: • Common types of microphones are (1) condenser; (2) magnetic; (3) dynamic; (4) ribbon; (5) piezoelectric; (6) carbon. • Vacuum tubes and transistors provide amplification by permitting the input to modulate a larger output current and voltage. • Analog recording media include mechanical, magnetic and optical storage. • Playback uses physical principles in which mechanical oscillations, magnetic domains and optical density variations produce electrical signals that are analogous to the recorded sound.