The Info List - Analog Recording

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Analog recording
Analog recording
(Greek, ana is "according to" and logos "relationship") is a technique used for the recording of analog signals which, among many possibilities, allows analog audio and analog video for later playback. Analog audio recording began with mechanical systems such as the phonautograph and phonograph. Later, electronic techniques such as wire recording and tape recorder were developed. Analog recording
Analog recording
methods store signals as a continuous signal in or on the media. The signal may be stored as a physical texture on a phonograph record, or a fluctuation in the field strength of a magnetic recording. This is different from digital recording where digital signals are quantized and represented as discrete numbers.


1 Phonautograph 2 The phonograph

2.1 Recording 2.2 Playback 2.3 Phonograph

3 Gramophone

3.1 Advantages 3.2 Problems

4 Telegraphone

4.1 Problems

5 Magnetophon

5.1 Advantages 5.2 Problems

6 Modern tape recorder 7 See also 8 References

Phonautograph[edit] The phonautograph is the earliest known device for recording sound. The phonograph[edit]

Edison and his Phonograph

The phonograph was the first machine used to capture and reproduce analog sound, and was invented by the well-known inventor Thomas Edison in 1877. Edison incorporated various elements into his Phonograph
that would become staples that can be found in recording devices to this day.[1] Recording[edit] For a sound to be recorded by the Phonograph, it has to go through three distinct steps. First, the sound enters a cone-shaped component of the device, called the microphone diaphragm. That sound causes the microphone diaphragm, which is connected to a small metal needle, to vibrate. The needle then vibrates in the same way, causing its sharp tip to etch a distinctive groove into a cylinder, which was made out of tinfoil. Playback[edit] In order to playback the sound recorded on one of the tinfoil cylinders, the recording process is essentially reversed. As the cylinder spins, the needle follows the groove created by the previous recording session. This causes the needle to vibrate, and then the diaphragm. This vibration comes out of the diaphragm, which is now functioning as a sort of sound amplification device, much like the bell on any wind instrument. The result is an audible reproduction of the originally recorded sound. Phonograph
problems[edit] Edison's phonograph was the first of its kind, but drawbacks were nevertheless obvious. The biggest of these, and the one that ended up being fixed first, came from the physical contact between the phonograph needle and the tinfoil diaphragm. Because the needle had to continually make contact with the groove in the diaphragm every time the recording was played, the groove would wear down. This meant that every single time a recording was played, it was one step closer to being gone forever.[2] Another problem with the phonograph was the permanence of its recordings. Unlike music today, which can be edited endlessly, the music captured by phonograph machines were single-take, live recordings.[2] The last problem with the phonograph was related to fidelity. Fidelity is the similarity/difference between the original recorded sound, and that same sound after it has been reproduced by a playback device, in this case the phonograph.[2] As can be expected from such an early audio recording machine, the fidelity of Edison's phonograph was extremely low. This lack of sound quality is why the phonograph was originally used to record speeches, meetings, and telephone calls, rather than music.[2] Gramophone[edit]

An early Berliner record

Fans of modern record players are already familiar with one very early improvement on the phonograph, known as the gramophone. Inventor Emile Berliner created the device in 1887, only ten years after Edison's original device.[3] Advantages[edit] Berliner's main improvement to the phonograph was related to the component of the device that actually held the recorded information. The previously used tinfoil cylinders were awkwardly shaped, making them hard to store.[2] They could also not be reproduced economically, which was another reason why they were not seen as a viable option for recorded music.[2] Berliner realized these disadvantages, and set out to create a better version of the tinfoil cylinder. What he came up with was not a cylinder at all, but was rather a flat circular disc much like modern vinyl records. These discs could not only be easily stacked and stored for safe-keeping, but were also comparatively easy to reproduce. This quality allowed for the mass production of recorded discs, which was the first step towards commercially recorded music.[2] Problems[edit] Unfortunately, though the Gramophone was a large step up from the Phonograph
commercially, it still had many of the same problems.[2] The mass production possibilities created by Berliner’s flat discs got companies thinking about recording music, but since nothing had been done to address the low fidelity issue, the industry had yet to really take off. The problems with finality and breakdown of recordings started by the Phonograph
were equally as prominent with the Gramophone.[2] Telegraphone[edit]

Early mechanical drawings of the telegraphone

The next great advancement in analog sound recording came in the form of the telegraphone, which was created by Danish inventor Valdemar Poulsen between 1898 and 1900. This machine was vastly different from the gramophone or the phonograph, in that instead of recording sound mechanically, it recorded using a process called electromagnetism.[2][4][5] Poulsen was able to transmit an electrical signal, much like the one that would broadcast over the radio or a telephone, and then capture it on a magnetizable element, in this case a length of steel wire, which was wrapped around a bass drum.[2] Problems[edit] Poulsen's telegraphone was not without its share of problems. First, the reels of steel wire were extremely heavy, weighing approximately 40 pounds (18 kg) each. Secondly, steel's scarcity at the time raised the price of recording; a single minute of recording would cost a full dollar, and the price was further increased because multiple recordings were necessary in order to capture the best rendition. Moreover, steel wire could be dangerous, with a risk comparable to that of a bandsaw.[2] Like the recording devices that came before it, the telegraphone recordings were nearly impossible to edit. Rather than cutting and splicing together multiple takes, as could easily be done with scissors or a computer in future recording devices, this machine required both a welding torch and a soldering tool to modify.[2] Magnetophon[edit]

The Magnetophon

In 1935, inventor Fritz Pfleumer
Fritz Pfleumer
took the electromagnetic recording idea and took it to the next level.[2] Rather than using heavy, expensive, and dangerous steel wire like Poulsen, Pfleumer realized that he could coat normal strips of paper with tiny particles of iron. The iron would allow the paper to be magnetized in the same way as the steel wire, but would eliminate most of its shortcomings. The magnetophon operated with a process nearly identical to that of the telegraphone. An inscriber, called the recording head, passes over the electromagnetic paper strip, creating patterns of varying magnetic polarity within it, which can later be played back. The playback is achieved using a reversal of the recording process. The pre-magnetized paper, which had come to be known as tape, passed over a coil, creating changes in magnetic flux. These changes were translated into an electric current, which when amplified produced a replica of the previously recorded sounds.[2] Advantages[edit] There were many advantages of tape recording, but the most important was that it led to the development of multitracking. Multitracking occurs when multiple takes of a performance, which were recorded at separate times, are brought together to play simultaneously. This is the method all recording studios use to this day, in order to record all of the separate instruments of a song, and get the best possible takes from all of the musicians.[2] A reel of tape could also hold far more recorded information than previous mediums. For instance, Berliner's discs held only a few minutes of recording, meaning that each disc usually contained a single song, or multiple short clips. Pfleumer's tape reels, on the other hand, could hold up to thirty minutes of sound. This ability is what eventually led to the concept of a music "album", or collection of multiple songs.[2] Problems[edit] The original magnetophon had its share of setbacks as well. Namely, the problem of low fidelity found in previous devices had yet to be solved. Though audiences and inventors had not yet experienced what high fidelity recording would even sound like, they knew that the sound they were hearing from recordings needed to be improved before any kind of recorded music industry could be expected.[2] Modern tape recorder[edit] The introduction of tape bias to recording systems improved fidelity to acceptable and eventually high-fidelity performance. Adding a DC bias to the signal sent to the recording head reduced distortion in the recording. The use of an AC bias further reduced distortion and greatly improved the frequency response of recording systems.[2] See also[edit]

Analog recording
Analog recording
vs. digital recording History of sound recording Timeline of audio formats Magnetic tape


^ Brain, Marshall (2000-04-01). "How Analog and Digital Recording Works". howstuffworks.com. Retrieved 2013-08-05.  ^ a b c d e f g h i j k l m n o p q r s Milner 2009, pp. 1-416. ^ "First Phonographs and Graphophones, and then Gramophones". Archived from the original on 2013-04-19. Retrieved 2013-08-05.  ^ "Recording History". Archived from the original on 2013-07-15. Retrieved 2013-08-05.  ^ "Inventing the Wire Recorder". Archived from the original on 2013-05-14. Retrieved 2013-08-05. 

v t e

Analog and digital audio broadcasting




Frequency allocations

LW (LF) MW (MF) SW (HF) VHF (low / mid / high) L band
L band

Digital systems



Frequency allocations

C band Ku band L band S band

Digital systems


Commercial radio providers

1worldspace Sirius XM Holdings SiriusXM Canada



Subcarrier signals


Related topics

Technical (audio)

Audio data compression Audio signal processing

Technical ( AM stereo
AM stereo

Belar C-QUAM Harris Kahn-Hazeltine Magnavox

Technical (emission)

AM broadcasting AM expanded band Cable radio Digital radio Error detection and correction FM broadcast band FM broadcasting Multipath propagation Shortwave relay station


History of radio International broadcasting

Comparison of radio systems

v t e

Physical audio recording formats


Phonautogram (1857) Phonograph
cylinder (1877) Phonograph
record (1894) Wire recording
Wire recording
(1898) Sound-on-film
(1919) Tefifon
(1936) Reel-to-reel tape (1940s) SoundScriber
(1945) Gray Audograph
Gray Audograph
(1945) Dictabelt (1947) LP record
LP record
(1948) On-the-ribs recordings (late 1940s) RCA tape cartridge (1958) Fidelipac
(1959) Stereo-Pak
(1962) Compact Cassette
Compact Cassette
(1963) 8-track (1964) PlayTape
(1966) Mini-Cassette
(1967) Microcassette
(1969) Steno-Cassette
(1971) Elcaset
(1976) Picocassette (1985)


(1976) X80/ ProDigi (1980) Compact disc
Compact disc
(1982) DASH (1982) Digital Audio Tape
Digital Audio Tape
(1987) ADAT
(1991) MiniDisc
(1992) NT (1992) Digital Compact Cassette
Compact Cassette
(1992) DA-88 (1993) High Definition Compatible Digital
High Definition Compatible Digital
(1995) 5.1 Music Disc (1997) Super Audio CD
Super Audio CD
(1999) DVD-Audio
(2000) USB flash drive (as audio format) (2004) Hi-MD
(2004) slotMusic (2008) BD-Audio
(2008) HFPA (2013)

v t e

Music technology

Music technology

Mechanical Electrical Electronic and digital


Audio channel Audio console
Audio console
(mixing board) Binaural recording Digital audio
Digital audio
workstation (DAW) Effects unit Equalizer Headphones Microphone Microphone
preamplifier Monitor speaker Multitrack recording Music production Music sequencer Outboard gear

Recording media

record Magnetic tape Compact cassette Compact disc DAT Hard disk MiniDisc MP3 Opus

Analog recording

8-track cartridge Amplifier Cassette deck Comparison of analog and digital recording Experimental musical instrument Phonograph Player piano Reel-to-reel audio tape recording Tape recorder

Playback transducers

Loudspeaker Headphones Monitor speaker PA system Sound
reinforcement system Speaker enclosure Subwoofer

Digital audio

Digital recording Digital signal processing

Live music

Audio console Bass amplifier Effects unit Foldback Guitar amplifier Keyboard amplifier PA system Radio Reverberation Sound
reinforcement system

Electronic music

Chiptune Circuit bending Drum machine Electronic drums Electronic musical instrument MIDI MIDI
controller Music workstation Sampler Sequencer Sound
module Synthesizer Theremin


Digital audio
Digital audio
editor Digital audio
Digital audio
workstation GarageBand ProTools Scorewriter Software
effect processor Software
sampler Software


Audio engineer DJ Guitar technician Mixing engineer Monitor engineer Piano tuner Record producer Re-recording mixer Sound
designer Sound
follower Sound
operator Sound
recording engineer Tape op

People and organizations

Audio Engineering Society Goji Electronics Institute of Broadcast Sound Lejaren Hiller IRCAM Max Mathews Musical Electronics Library Professional Lighting and Sound
Association Robert Moog SMPTE STEIM

Related topics

Audiophile High fidelity Home audio Home cinema Music store Professional audio store New Interfaces for Musical Expression
New Interfaces for Musical Expression