Vocoder
Encyclopedia
A vocoder is an analysis/synthesis system, mostly used for speech. In the encoder
, the input is passed through a multiband filter, each band is passed through an envelope follower, and the control signals from the envelope followers are communicated to the decoder. The decoder applies these (amplitude) control signals to corresponding filters in the (re)synthesizer.
It was originally developed as a speech coder for telecommunications applications in the 1930s, the idea being to code
speech for transmission. Its primary use in this fashion is for secure radio communication, where voice has to be encrypted
and then transmitted. The advantage of this method of "encryption" is that no 'signal' is sent, but rather envelopes of the bandpass filters. The receiving unit needs to be set up in the same channel configuration to resynthesize a version of the original signal spectrum. The vocoder as both hardware
and software has also been used extensively as an electronic musical instrument
.
Whereas the vocoder analyzes speech, transforms it into electronically transmitted information, and recreates it, The Voder (from Voice Operating Demonstrator) generates synthesized speech by means of a console with fifteen touch-sensitive keys and a pedal, basically consisting of the "second half" of the vocoder, but with manual filter controls, needing a highly trained operator.
consists of sounds generated by the opening and closing of the glottis
by the vocal cords
, which produces a periodic waveform with many harmonic
s. This basic sound is then filter
ed by the nose and throat (a complicated resonant
piping system) to produce differences in harmonic content (formant
s) in a controlled way, creating the wide variety of sounds used in speech. There is another set of sounds, known as the unvoiced and plosive
sounds, which are created or modified by the mouth in different fashions.
The vocoder examines speech by measuring how its spectral characteristics change over time. This results in a series of numbers representing these modified frequencies at any particular time as the user speaks. In simple terms, the signal is split into a number of frequency bands (the larger this number, the more accurate the analysis) and the level of signal present at each frequency band gives the instantaneous representation of the spectral energy content.
Thus, the vocoder dramatically reduces the amount of information needed to store speech, from a complete recording to a series of numbers. To recreate speech, the vocoder simply reverses the process, processing a broadband noise source by passing it through a stage that filters the frequency content based on the originally recorded series of numbers.
Information about the instantaneous frequency (as distinct from spectral characteristic) of the original voice signal is discarded; it wasn't important to preserve this for the purposes of the vocoder's original use as an encryption aid, and it is this "dehumanizing" quality of the vocoding process that has made it useful in creating special voice effects in popular music and audio entertainment.
vocoder systems use a number of frequency channels, all tuned to different frequencies (using band-pass filter
s). The various values of these filters are stored not as the raw numbers, which are all based on the original fundamental frequency, but as a series of modifications to that fundamental needed to modify it into the signal seen in the output of that filter. During playback these settings are sent back into the filters and then added together, modified with the knowledge that speech typically varies between these frequencies in a fairly linear way. The result is recognizable speech, although somewhat "mechanical" sounding. Vocoders also often include a second system for generating unvoiced sounds, using a noise generator instead of the fundamental frequency.
The first experiments with a vocoder were conducted in 1928 by Bell Labs
engineer Homer Dudley
, who was granted a patent for it on March 21, 1939.
The Vocoder was introduced to the public at the AT&T building at the 1939-1940 New York World's Fair. Dudley's vocoder was used in the SIGSALY
system, which was built by Bell Labs
engineers (Alan Turing
was briefly involved) in 1943. The SIGSALY
system was used for encrypted high-level communications during World War II
. Later work in this field has been conducted by James Flanagan
.
The RALCWI Vocoder operates on a “frame-by-frame” basis. The 20ms source voice frame consists of 160 samples of linear 16-bit PCM sampled at 8 kHz. The Voice Encoder performs voice analysis at the high time resolution (8 times per frame) and forms a set of estimated parameters for each voice segment. All of the estimated parameters are quantized to produce 41-, 48- or 55-bit frames, using Vector Quantization (VQ) of different types. All of the vector quantizers were trained on a mixed multi-language voice base, which contains voice samples in both Eastern and Western languages.
The product is the result of a co-operation between CML Microcircuits and SPIRIT DSP. The co-operation combines CML’s 39-year history of developing mixed-signal semiconductors for professional and leisure communication applications, with SPIRIT’s experience in embedded
voice products.
Since inception in 1992 SPIRIT is a Russian company that implements mostly standard audio and data communication software products, primarily outside the US.
Founded in 1968, CML Microcircuits are involved in the design, development and supply of low-power analogue, digital and mixed-signal semiconductor
s for telecommunications systems worldwide. CML IC’s, the CMX608, CMX618 and the CMX638 market to worldwide communication markets based upon SPIRIT’s
proprietary Low Bit-Rate Vocoder technology.
a demonstration of Voder (not Vocoder).
was an It consisted of a series of Oscillators using radio valves to produce tones, and gas discharge tubes to produce noise (hiss), the sound or output was modified using a series of filters. The filters were controlled by a set of keys and a foot pedal to convert the hisses and tones into vowels, consonants, and inflections. This was a complex machine to operate, and produce sounds similar to human speech. In 1948 Werner Meyer-Eppler
recognized the capability of the Voder machine to generate electronic music.
, whereby the target signal's spectral envelope (formant) is estimated by an all-pole IIR
filter
. In linear prediction coding, the all-pole filter replaces the bandpass filter bank of its predecessor and is used at the encoder to whiten the signal (i.e., flatten the spectrum) and again at the decoder to re-apply the spectral shape of the target speech signal.
One advantage of this type of filtering is that the location of the linear predictor's spectral peaks is entirely determined by the target signal, and can be as precise as allowed by the time period to be filtered. This is in contrast with vocoders realized using fixed-width filter banks, where spectral peaks can generally only be determined to be within the scope of a given frequency band. LP filtering also has disadvantages in that signals with a large number of constituent frequencies may exceed the number of frequencies that can be represented by the linear prediction filter. This restriction is the primary reason that LP coding is almost always used in tandem with other methods in high-compression voice coders.
). The sampling resolution is typically at least 12 or more bits per sample resolution (16 is standard), for a final data rate in the range of 96-128 kbit/s. However, a good vocoder can provide a reasonable good simulation of voice with as little as 2.4 kbit/s of data.
'Toll Quality' voice coders, such as ITU G.729, are used in many telephone networks. G.729 in particular has a final data rate of 8 kbit/s with superb voice quality. G.723 achieves slightly worse quality at data rates of 5.3 kbit/s and 6.4 kbit/s. Many voice systems use even lower data rates, but below 5 kbit/s voice quality begins to drop rapidly.
Several vocoder systems are used in NSA encryption systems
:
(ADPCM is not a proper vocoder but rather a waveform codec. ITU
has gathered G.721 along with some other ADPCM codecs into G.726.)
Vocoders are also currently used in developing psychophysics, linguistics, computational neuroscience and cochlear implant research.
Modern vocoders that are used in communication equipment and in voice storage devices today are based on the following algorithms:
For music
al applications, a source of musical sounds is used as the carrier, instead of extracting the fundamental frequency. For instance, one could use the sound of a synthesizer
as the input to the filter bank, a technique that became popular in the 1970s.
details of Siemens Electronic Music Studio, exhibited on Deutsches Museum
.
In 1968, Robert Moog
developed one of the first solid-state
musical vocoder for electronic music studio of University at Buffalo
.
In 1969, Bruce Haack
built a prototype vocoder, named "Farad" after Michael Faraday
, and it was featured on his rock album The Electric Lucifer released in the same year.
a sample of earlier Vocoder.
In 1970 Wendy Carlos
and Robert Moog
built another musical vocoder, a 10-band device inspired by the vocoder designs of Homer Dudley. It was originally called a spectrum encoder-decoder, and later referred to simply as a vocoder. The carrier signal came from a Moog modular synthesizer
, and the modulator from a microphone
input. The output of the 10-band vocoder was fairly intelligible, but relied on specially articulated speech. Later improved vocoders use a high-pass filter to let some sibilance
through from the microphone; this ruins the device for its original speech-coding application, but it makes the "talking synthesizer" effect much more intelligible.
Carlos and Moog's vocoder was featured in several recordings, including the soundtrack
to Stanley Kubrick
's A Clockwork Orange
in which the vocoder sang the vocal part of Beethoven
's "Ninth Symphony". Also featured in the soundtrack was a piece called "Timesteps," which featured the vocoder in two sections. "Timesteps" was originally intended as merely an introduction to vocoders for the "timid listener", but Kubrick chose to include the piece on the soundtrack, much to the surprise of Wendy Carlos.
In 1972, Isao Tomita
's first electronic music
album Electric Samurai: Switched on Rock was an early attempt at applying speech synthesis
technique in electronic rock and pop music. The album featured electronic renditions of contemporary rock
and pop
songs, while utilizing synthesized voices in place of human voices. In 1974, he utilized synthesized voices again in his popular classical music
album Snowflakes are Dancing
, which became a worldwide success and helped popularize electronic music.
Kraftwerk
's Autobahn (1974) was one of the first successful pop/rock albums to feature vocoder vocals. Another of the early songs to feature a vocoder was "The Raven
" on the 1976 album Tales of Mystery and Imagination
by progressive rock
band The Alan Parsons Project
; the vocoder also was used on later albums such as I Robot
. Following Alan Parsons
' example, vocoders began to appear in pop music
in the late 1970s, for example, on disco
recordings. Jeff Lynne
of Electric Light Orchestra
used the vocoder in several albums such as Time
(featuring the Roland VP-330 Plus MkI). ELO songs such as "Mr. Blue Sky
" and "Sweet Talkin' Woman
" both from Out of the Blue
(1977) use the vocoder extensively. Featured on the album are the EMS Vocoder 2000W MkI, and the EMS Vocoder (-System) 2000 (W or B, MkI or II).
Giorgio Moroder
made extensive use of the vocoder on the 1975 album Einzelganger and on the 1977 album From Here to Eternity. Another example is Pink Floyd
's album Animals, where the band put the sound of a barking dog through the device. Vocoders are often used to create the sound of a robot talking, as in the Styx
song "Mr. Roboto
". It was also used for the introduction to the Main Street Electrical Parade
at Disneyland.
Vocoders have appeared on pop recordings from time to time ever since, most often simply as a special effect
rather than a featured aspect of the work. However, many experimental electronic artists of the New Age music
genre often utilize vocoder in a more comprehensive manner in specific works, such as Jean Michel Jarre
(on Zoolook
, 1984) and Mike Oldfield
(on QE2
, 1980 and Five Miles Out
, 1982). There are also some artists who have made vocoders an essential part of their music, overall or during an extended phase. Examples include the German synthpop
group Kraftwerk
, Stevie Wonder ["Send One Your Love", "A Seed's a Star"] and jazz/fusion keyboardist Herbie Hancock
during his late 1970s period.
In 1982 Neil Young used a Sennheiser Vocoder VSM201 on six of the nine tracks on 'Trans'.
, Auto-Tune
,
a sample of Auto-Tune
effect (a.k.a. T-Pain effect).
linear prediction vocoders, speech synthesis
,
a sample of earlier computer based speech synthesis
and song synthesis, by John Larry Kelly, Jr. and Louis Gerstman at Bell Labs
, using IBM 704
computer. The demo song “Daisy Bell
”, musical accompanied by Max Mathews
, impressed Arthur C. Clarke
and later he used it in the climactic scene of screenplay for his novel 2001: A Space Odyssey.
a sample of speech synthesis
.
ring modulation
and comb filter
.
used a carbon throat microphone wired in such a way as to modulate his electric steel guitar sound. from
a sample of Singing guitar.
The mic, originally developed for military pilot communications, was placed on the throat of Rey's wife Luise King (one of The King Sisters
), who stood behind a curtain and mouthed the words, along with the guitar lines. The novel-sounding combination was called "Singing Guitar", but was not developed further.
Rey also created a somewhat similar "talking" effect, by manipulating the tone controls of his Fender electric guitar, but the vocal effect was less pronounced.
(1949), The Secret Life of Walter Mitty
(1947), the voice of Casey Junior the train
in Dumbo
(1941) and The Reluctant Dragon
(1941), the instruments in Rusty in Orchestraville, the piano in Sparky's Magic Piano
, and the airplane in Whizzer The Talking Airplane (1947). The Sonovox was also used in many radio station IDs produced by PAMS
of Dallas and JAM Creative Productions
. Lucille Ball
made one of her earliest film appearances during the 1930s in a Pathé Newsreel demonstrating the Sonovox.
The Sonovox makes an even earlier appearance in the 1940 film You'll Find Out
starring Kay Kyser and his orchestra, from
a sample of Sonovox.
Bela Lugosi, Boris Karloff, and Peter Lorre. Lugosi uses the Sonovox to portray the voice of a dead person during a seance.
appears in The Ventures
' Christmas Album
, released in 1965. In the song "Silver Bells", Red Rhodes
spoke through a talk box, distorting the phrase silver bells.
a sample of Talk box
.
and games, usually for robots or talking computers.
Encoder
An encoder is a device, circuit, transducer, software program, algorithm or person that converts information from one format or code to another, for the purposes of standardization, speed, secrecy, security, or saving space by shrinking size.-Media:...
, the input is passed through a multiband filter, each band is passed through an envelope follower, and the control signals from the envelope followers are communicated to the decoder. The decoder applies these (amplitude) control signals to corresponding filters in the (re)synthesizer.
It was originally developed as a speech coder for telecommunications applications in the 1930s, the idea being to code
Code
A code is a rule for converting a piece of information into another form or representation , not necessarily of the same type....
speech for transmission. Its primary use in this fashion is for secure radio communication, where voice has to be encrypted
Encryption
In cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
and then transmitted. The advantage of this method of "encryption" is that no 'signal' is sent, but rather envelopes of the bandpass filters. The receiving unit needs to be set up in the same channel configuration to resynthesize a version of the original signal spectrum. The vocoder as both hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
and software has also been used extensively as an electronic musical instrument
Electronic musical instrument
An electronic musical instrument is a musical instrument that produces its sounds using electronics. Such an instrument sounds by outputting an electrical audio signal that ultimately drives a loudspeaker....
.
Whereas the vocoder analyzes speech, transforms it into electronically transmitted information, and recreates it, The Voder (from Voice Operating Demonstrator) generates synthesized speech by means of a console with fifteen touch-sensitive keys and a pedal, basically consisting of the "second half" of the vocoder, but with manual filter controls, needing a highly trained operator.
Vocoder theory
The human voiceHuman voice
The human voice consists of sound made by a human being using the vocal folds for talking, singing, laughing, crying, screaming, etc. Its frequency ranges from about 60 to 7000 Hz. The human voice is specifically that part of human sound production in which the vocal folds are the primary...
consists of sounds generated by the opening and closing of the glottis
Glottis
The glottis is defined as the combination of the vocal folds and the space in between the folds .-Function:...
by the vocal cords
Vocal folds
The vocal folds, also known commonly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx...
, which produces a periodic waveform with many harmonic
Harmonic
A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency, i.e. if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f, . . . etc. The harmonics have the property that they are all periodic at the fundamental...
s. This basic sound is then filter
Audio filter
An audio filter is a frequency dependent amplifier circuit, working in the audio frequency range, 0 Hz to beyond 20 kHz. Many types of filters exist for applications including graphic equalizers, synthesizers, sound effects, CD players and virtual reality systems.Being a frequency dependent...
ed by the nose and throat (a complicated resonant
Resonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
piping system) to produce differences in harmonic content (formant
Formant
Formants are defined by Gunnar Fant as 'the spectral peaks of the sound spectrum |P|' of the voice. In speech science and phonetics, formant is also used to mean an acoustic resonance of the human vocal tract...
s) in a controlled way, creating the wide variety of sounds used in speech. There is another set of sounds, known as the unvoiced and plosive
Stop consonant
In phonetics, a plosive, also known as an occlusive or an oral stop, is a stop consonant in which the vocal tract is blocked so that all airflow ceases. The occlusion may be done with the tongue , lips , and &...
sounds, which are created or modified by the mouth in different fashions.
The vocoder examines speech by measuring how its spectral characteristics change over time. This results in a series of numbers representing these modified frequencies at any particular time as the user speaks. In simple terms, the signal is split into a number of frequency bands (the larger this number, the more accurate the analysis) and the level of signal present at each frequency band gives the instantaneous representation of the spectral energy content.
Thus, the vocoder dramatically reduces the amount of information needed to store speech, from a complete recording to a series of numbers. To recreate speech, the vocoder simply reverses the process, processing a broadband noise source by passing it through a stage that filters the frequency content based on the originally recorded series of numbers.
Information about the instantaneous frequency (as distinct from spectral characteristic) of the original voice signal is discarded; it wasn't important to preserve this for the purposes of the vocoder's original use as an encryption aid, and it is this "dehumanizing" quality of the vocoding process that has made it useful in creating special voice effects in popular music and audio entertainment.
Analog vocoders
Most analogAnalog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
vocoder systems use a number of frequency channels, all tuned to different frequencies (using band-pass filter
Band-pass filter
A band-pass filter is a device that passes frequencies within a certain range and rejects frequencies outside that range.Optical band-pass filters are of common usage....
s). The various values of these filters are stored not as the raw numbers, which are all based on the original fundamental frequency, but as a series of modifications to that fundamental needed to modify it into the signal seen in the output of that filter. During playback these settings are sent back into the filters and then added together, modified with the knowledge that speech typically varies between these frequencies in a fairly linear way. The result is recognizable speech, although somewhat "mechanical" sounding. Vocoders also often include a second system for generating unvoiced sounds, using a noise generator instead of the fundamental frequency.
The first experiments with a vocoder were conducted in 1928 by Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
engineer Homer Dudley
Homer Dudley
Homer W. Dudley was a pioneering electronic and acoustic engineer who created the first electronic voice synthesizer for Bell Labs in the 1930s and led the development of a method of sending secure voice transmissions during World War Two....
, who was granted a patent for it on March 21, 1939.
The Vocoder was introduced to the public at the AT&T building at the 1939-1940 New York World's Fair. Dudley's vocoder was used in the SIGSALY
SIGSALY
In cryptography, SIGSALY was a secure speech system used in World War II for the highest-level Allied communications....
system, which was built by Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
engineers (Alan Turing
Alan Turing
Alan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
was briefly involved) in 1943. The SIGSALY
SIGSALY
In cryptography, SIGSALY was a secure speech system used in World War II for the highest-level Allied communications....
system was used for encrypted high-level communications during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. Later work in this field has been conducted by James Flanagan
James Flanagan (engineer)
James Loton Flanagan is an electrical engineer, and was Rutgers University's vice president for research until 2004. He is also director of Rutgers' Center for Advanced Information Processing and the Board of Governors Professor of Electrical and Computer Engineering.He was chosen as the 2005...
.
Modern Vocoder Technology
RALCWI technology uses unique proprietary signal decomposition and parameter encoding methods, ensuring high voice quality at high compression ratios. The voice quality of RALCWI-class Vocoders, as estimated by independent listeners, is similar to that provided by standard Vocoders running at bit rates above 4000 bit/s. The Mean Opinion Score (MOS) of voice quality for this Vocoder is about 3.5-3.6. This value was determined by a paired comparison method, performing listening tests of developed and standard voice Vocoders.The RALCWI Vocoder operates on a “frame-by-frame” basis. The 20ms source voice frame consists of 160 samples of linear 16-bit PCM sampled at 8 kHz. The Voice Encoder performs voice analysis at the high time resolution (8 times per frame) and forms a set of estimated parameters for each voice segment. All of the estimated parameters are quantized to produce 41-, 48- or 55-bit frames, using Vector Quantization (VQ) of different types. All of the vector quantizers were trained on a mixed multi-language voice base, which contains voice samples in both Eastern and Western languages.
RALCWI History
Waveform-Interpolative (WI) vocoder was developed in AT&T Bell Laboratories around 1995 by W.B. Kleijn, and subsequently a low- complexity version was developed by AT&T for the DoD secure vocoder competition. Notable enhancements to the WI coder were made at UCSB. AT&T holds the core patents related to WI, and other institutes hold additional patents. Using these patents as a part of WI coder implementation requires licensing from all IPR holders.The product is the result of a co-operation between CML Microcircuits and SPIRIT DSP. The co-operation combines CML’s 39-year history of developing mixed-signal semiconductors for professional and leisure communication applications, with SPIRIT’s experience in embedded
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
voice products.
Since inception in 1992 SPIRIT is a Russian company that implements mostly standard audio and data communication software products, primarily outside the US.
Founded in 1968, CML Microcircuits are involved in the design, development and supply of low-power analogue, digital and mixed-signal semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
s for telecommunications systems worldwide. CML IC’s, the CMX608, CMX618 and the CMX638 market to worldwide communication markets based upon SPIRIT’s
SPIRIT DSP
SPIRIT DSP develops embedded software solutions for real-time voice and video communication over IP networks – voice and video engines.- Products and Solutions :...
proprietary Low Bit-Rate Vocoder technology.
Vocoder Applications
- Terminal equipment for Digital Mobile Radio (DMR)Embedded systemAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
based systems. - Digital Trunking
- DMR TDMA
- Digital Voice Scrambling and Encryption
- Digital WLLWireless local loopWireless local loop , is a term for the use of a wireless communications link as the "last mile / first mile" connection for delivering plain old telephone service and/or broadband Internet to telecommunications customers....
- Voice Storage and Playback Systems
- Messaging Systems
- VoIP Systems
- Voice Pagers
- Regenerative Digital Voice Repeaters
Voder
The Voder (Voice Operating Demonstrator), an earlier speech synthesizer demonstrated in 1939,a demonstration of Voder (not Vocoder).
was an It consisted of a series of Oscillators using radio valves to produce tones, and gas discharge tubes to produce noise (hiss), the sound or output was modified using a series of filters. The filters were controlled by a set of keys and a foot pedal to convert the hisses and tones into vowels, consonants, and inflections. This was a complex machine to operate, and produce sounds similar to human speech. In 1948 Werner Meyer-Eppler
Werner Meyer-Eppler
Werner Meyer-Eppler , was a German physicist, experimental acoustician, phoneticist, and information theorist....
recognized the capability of the Voder machine to generate electronic music.
Linear prediction-based vocoders
Since the late 1970s, most non-musical vocoders have been implemented using linear predictionLinear prediction
Linear prediction is a mathematical operation where future values of a discrete-time signal are estimated as a linear function of previous samples....
, whereby the target signal's spectral envelope (formant) is estimated by an all-pole IIR
Infinite impulse response
Infinite impulse response is a property of signal processing systems. Systems with this property are known as IIR systems or, when dealing with filter systems, as IIR filters. IIR systems have an impulse response function that is non-zero over an infinite length of time...
filter
Digital filter
In electronics, computer science and mathematics, a digital filter is a system that performs mathematical operations on a sampled, discrete-time signal to reduce or enhance certain aspects of that signal. This is in contrast to the other major type of electronic filter, the analog filter, which is...
. In linear prediction coding, the all-pole filter replaces the bandpass filter bank of its predecessor and is used at the encoder to whiten the signal (i.e., flatten the spectrum) and again at the decoder to re-apply the spectral shape of the target speech signal.
One advantage of this type of filtering is that the location of the linear predictor's spectral peaks is entirely determined by the target signal, and can be as precise as allowed by the time period to be filtered. This is in contrast with vocoders realized using fixed-width filter banks, where spectral peaks can generally only be determined to be within the scope of a given frequency band. LP filtering also has disadvantages in that signals with a large number of constituent frequencies may exceed the number of frequencies that can be represented by the linear prediction filter. This restriction is the primary reason that LP coding is almost always used in tandem with other methods in high-compression voice coders.
Modern vocoder implementations
Even with the need to record several frequencies, and the additional unvoiced sounds, the compression of the vocoder system is impressive. Standard speech-recording systems capture frequencies from about 500 Hz to 3400 Hz, where most of the frequencies used in speech lie, typically using a sampling rate of 8 kHz (slightly greater than the Nyquist rateNyquist rate
In signal processing, the Nyquist rate, named after Harry Nyquist, is two times the bandwidth of a bandlimited signal or a bandlimited channel...
). The sampling resolution is typically at least 12 or more bits per sample resolution (16 is standard), for a final data rate in the range of 96-128 kbit/s. However, a good vocoder can provide a reasonable good simulation of voice with as little as 2.4 kbit/s of data.
'Toll Quality' voice coders, such as ITU G.729, are used in many telephone networks. G.729 in particular has a final data rate of 8 kbit/s with superb voice quality. G.723 achieves slightly worse quality at data rates of 5.3 kbit/s and 6.4 kbit/s. Many voice systems use even lower data rates, but below 5 kbit/s voice quality begins to drop rapidly.
Several vocoder systems are used in NSA encryption systems
NSA encryption systems
The National Security Agency took over responsibility for all U.S. Government encryption systems when it was formed in 1952. The technical details of most NSA-approved systems are still classified, but much more about its early systems has become known and its most modern systems share at least...
:
- LPC-10, FIPSFIPS- Computer :*FIPS , Fully Interactive Partition Splitter, a disk partitioner*Federal Information Processing Standard, United States government standards*FTC Fair Information Practice, FIPs, US Federal Trade Commission guidelines- People :...
Pub 137, 2400 bit/s, which uses linear predictive codingLinear predictive codingLinear predictive coding is a tool used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive model... - Code-excited linear prediction (CELP), 2400 and 4800 bit/s, Federal Standard 1016, used in STU-IIISTU-IIISTU-III is a family of secure telephones introduced in 1987 by the NSA for use by the United States government, its contractors, and its allies. STU-III desk units look much like typical office telephones, plug into a standard telephone wall jack and can make calls to any ordinary phone user...
- Continuously variable slope delta modulationContinuously variable slope delta modulationContinuously variable slope delta modulation is a voice coding method. It is a delta modulation with variable step size Continuously variable slope delta modulation (CVSD or CVSDM) is a voice coding method. It is a delta modulation with variable step size Continuously variable slope delta...
(CVSD), 16 kbit/s, used in wide band encryptors such as the KY-57KY-57The Speech Security Equipment , TSEC/KY-57, is a portable, tactical cryptographic device in the VINSON family, designed to provide voice encryption for a range of military communication devices such as radio or telephone....
. - Mixed-excitation linear prediction (MELP), MIL STD 3005, 2400 bit/s, used in the Future Narrowband Digital Terminal FNBDT, NSANational Security AgencyThe National Security Agency/Central Security Service is a cryptologic intelligence agency of the United States Department of Defense responsible for the collection and analysis of foreign communications and foreign signals intelligence, as well as protecting U.S...
's 21st century secure telephone. - Adaptive Differential Pulse Code Modulation (ADPCMPulse-code modulationPulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
), former ITU-T G.721, 32 kbit/s used in STESecure Terminal EquipmentSecure Terminal Equipment is the U.S. Government's current , encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128k bits per second and are all digital...
secure telephone
(ADPCM is not a proper vocoder but rather a waveform codec. ITU
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...
has gathered G.721 along with some other ADPCM codecs into G.726.)
Vocoders are also currently used in developing psychophysics, linguistics, computational neuroscience and cochlear implant research.
Modern vocoders that are used in communication equipment and in voice storage devices today are based on the following algorithms:
- Algebraic code-excited linear prediction (ACELP 4.7 kbit/s – 24 kbit/s)
- Mixed-excitation linear prediction (MELPe 2400, 1200 and 600 bit/s)
- Multi-band excitation (AMBE 2000 bit/s – 9600 bit/s)
- Sinusoidal-Pulsed Representation (SPR 300 bit/s – 4800 bit/s)
- Tri-wave excited linear prediction (TWELP 2400 – 3600 bit/s)
Musical applications
Music
Music is an art form whose medium is sound and silence. Its common elements are pitch , rhythm , dynamics, and the sonic qualities of timbre and texture...
al applications, a source of musical sounds is used as the carrier, instead of extracting the fundamental frequency. For instance, one could use the sound of a synthesizer
Synthesizer
A synthesizer is an electronic instrument capable of producing sounds by generating electrical signals of different frequencies. These electrical signals are played through a loudspeaker or set of headphones...
as the input to the filter bank, a technique that became popular in the 1970s.
Musical history
One of the first attempt to divert vocoder to create music may be a “Siemens Synthesizer” at Siemens Studio for Electronic Music, developed between 1956-1959.details of Siemens Electronic Music Studio, exhibited on Deutsches Museum
Deutsches Museum
The Deutsches Museum in Munich, Germany, is the world's largest museum of technology and science, with approximately 1.5 million visitors per year and about 28,000 exhibited objects from 50 fields of science and technology. The museum was founded on June 28, 1903, at a meeting of the Association...
.
In 1968, Robert Moog
Robert Moog
Robert Arthur Moog , commonly called Bob Moog was an American pioneer of electronic music, best known as the inventor of the Moog synthesizer.-Life:...
developed one of the first solid-state
Solid state (electronics)
Solid-state electronics are those circuits or devices built entirely from solid materials and in which the electrons, or other charge carriers, are confined entirely within the solid material...
musical vocoder for electronic music studio of University at Buffalo
University at Buffalo, The State University of New York
University at Buffalo, The State University of New York, also commonly known as the University at Buffalo or UB, is a public research university and a "University Center" in the State University of New York system. The university was founded by Millard Fillmore in 1846. UB has multiple campuses...
.
In 1969, Bruce Haack
Bruce Haack
Bruce Clinton Haack was a musician, composer, and pioneer of electronic music. He was born in Alberta, Canada.-From Alberta to New York :...
built a prototype vocoder, named "Farad" after Michael Faraday
Michael Faraday
Michael Faraday, FRS was an English chemist and physicist who contributed to the fields of electromagnetism and electrochemistry....
, and it was featured on his rock album The Electric Lucifer released in the same year.
a sample of earlier Vocoder.
In 1970 Wendy Carlos
Wendy Carlos
Wendy Carlos is an American composer and electronic musician. Carlos first came to notice in the late 1960s with recordings made on the Moog synthesizer, then a relatively new and unknown instrument; most notable were LPs of synthesized Bach and the soundtrack for Stanley Kubrick's film A...
and Robert Moog
Robert Moog
Robert Arthur Moog , commonly called Bob Moog was an American pioneer of electronic music, best known as the inventor of the Moog synthesizer.-Life:...
built another musical vocoder, a 10-band device inspired by the vocoder designs of Homer Dudley. It was originally called a spectrum encoder-decoder, and later referred to simply as a vocoder. The carrier signal came from a Moog modular synthesizer
Modular synthesizer
The modular synthesizer is a type of synthesizer consisting of separate specialized modules connected by wires to create a so-called patch. Every output generates a signal – an electric voltage of variable strength...
, and the modulator from a microphone
Microphone
A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...
input. The output of the 10-band vocoder was fairly intelligible, but relied on specially articulated speech. Later improved vocoders use a high-pass filter to let some sibilance
Sibilant consonant
A sibilant is a manner of articulation of fricative and affricate consonants, made by directing a stream of air with the tongue towards the sharp edge of the teeth, which are held close together. Examples of sibilants are the consonants at the beginning of the English words sip, zip, ship, chip,...
through from the microphone; this ruins the device for its original speech-coding application, but it makes the "talking synthesizer" effect much more intelligible.
Carlos and Moog's vocoder was featured in several recordings, including the soundtrack
Soundtrack
A soundtrack can be recorded music accompanying and synchronized to the images of a motion picture, book, television program or video game; a commercially released soundtrack album of music as featured in the soundtrack of a film or TV show; or the physical area of a film that contains the...
to Stanley Kubrick
Stanley Kubrick
Stanley Kubrick was an American film director, writer, producer, and photographer who lived in England during most of the last four decades of his career...
's A Clockwork Orange
A Clockwork Orange (film)
A Clockwork Orange is a 1971 film adaptation of Anthony Burgess's 1962 novel of the same name. It was written, directed and produced by Stanley Kubrick...
in which the vocoder sang the vocal part of Beethoven
Ludwig van Beethoven
Ludwig van Beethoven was a German composer and pianist. A crucial figure in the transition between the Classical and Romantic eras in Western art music, he remains one of the most famous and influential composers of all time.Born in Bonn, then the capital of the Electorate of Cologne and part of...
's "Ninth Symphony". Also featured in the soundtrack was a piece called "Timesteps," which featured the vocoder in two sections. "Timesteps" was originally intended as merely an introduction to vocoders for the "timid listener", but Kubrick chose to include the piece on the soundtrack, much to the surprise of Wendy Carlos.
In 1972, Isao Tomita
Isao Tomita
, often known simply as Tomita, is a Japanese music composer, regarded as one of the pioneers of electronic music and space music, and as one of the most famous producers of analog synthesizer arrangements...
's first electronic music
Electronic music
Electronic music is music that employs electronic musical instruments and electronic music technology in its production. In general a distinction can be made between sound produced using electromechanical means and that produced using electronic technology. Examples of electromechanical sound...
album Electric Samurai: Switched on Rock was an early attempt at applying speech synthesis
Speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...
technique in electronic rock and pop music. The album featured electronic renditions of contemporary rock
Rock music
Rock music is a genre of popular music that developed during and after the 1960s, particularly in the United Kingdom and the United States. It has its roots in 1940s and 1950s rock and roll, itself heavily influenced by rhythm and blues and country music...
and pop
Pop music
Pop music is usually understood to be commercially recorded music, often oriented toward a youth market, usually consisting of relatively short, simple songs utilizing technological innovations to produce new variations on existing themes.- Definitions :David Hatch and Stephen Millward define pop...
songs, while utilizing synthesized voices in place of human voices. In 1974, he utilized synthesized voices again in his popular classical music
Classical music
Classical music is the art music produced in, or rooted in, the traditions of Western liturgical and secular music, encompassing a broad period from roughly the 11th century to present times...
album Snowflakes are Dancing
Snowflakes are Dancing
Snowflakes Are Dancing is an electronic music album by Isao Tomita, recorded in 1974 and first released as a Quadradisc in April. The album consists entirely of Tomita's arrangements of Claude Debussy's "tone paintings", performed by Tomita on a Moog synthesizer...
, which became a worldwide success and helped popularize electronic music.
Kraftwerk
Kraftwerk
Kraftwerk is an influential electronic music band from Düsseldorf, Germany. The group was formed by Ralf Hütter and Florian Schneider in 1970, and was fronted by them until Schneider's departure in 2008...
's Autobahn (1974) was one of the first successful pop/rock albums to feature vocoder vocals. Another of the early songs to feature a vocoder was "The Raven
The Raven (song)
"The Raven" is a 1976 song by the Alan Parsons Project from their album Tales of Mystery and Imagination. The song is based on the Edgar Allan Poe poem of the same name. It is well-known as being one of the first rock songs to use a vocoder, developed by EMI, to distort vocals. It is also one of...
" on the 1976 album Tales of Mystery and Imagination
Tales of Mystery and Imagination
Tales of Mystery and Imagination is the debut album by the progressive rock group The Alan Parsons Project, released in 1976. The album's avant-garde soundscapes kept it from being a blockbuster, but the interesting lyrical and musical themes — retellings of horror stories and poetry by...
by progressive rock
Progressive rock
Progressive rock is a subgenre of rock music that developed in the late 1960s and early 1970s as part of a "mostly British attempt to elevate rock music to new levels of artistic credibility." John Covach, in Contemporary Music Review, says that many thought it would not just "succeed the pop of...
band The Alan Parsons Project
The Alan Parsons Project
The Alan Parsons Project was a British progressive rock band, active between 1975 and 1990, consisting of singer Eric Woolfson and keyboardist Alan Parsons surrounded by a varying number of session musicians....
; the vocoder also was used on later albums such as I Robot
I Robot (album)
I Robot is a progressive rock album recorded by The Alan Parsons Project, engineered by Alan Parsons and Eric Woolfson in 1977. It was released by Arista Records in 1977 and re-released on CD in 1984 and 2007. It was intended to be based on the I, Robot stories written by Isaac Asimov, and Woolfson...
. Following Alan Parsons
Alan Parsons
Alan Parsons is a British audio engineer, musician, and record producer. He was involved with the production of several significant albums, including The Beatles' Abbey Road and Let It Be, as well as Pink Floyd's The Dark Side of the Moon for which Pink Floyd credit him as an important contributor...
' example, vocoders began to appear in pop music
Pop music
Pop music is usually understood to be commercially recorded music, often oriented toward a youth market, usually consisting of relatively short, simple songs utilizing technological innovations to produce new variations on existing themes.- Definitions :David Hatch and Stephen Millward define pop...
in the late 1970s, for example, on disco
Disco
Disco is a genre of dance music. Disco acts charted high during the mid-1970s, and the genre's popularity peaked during the late 1970s. It had its roots in clubs that catered to African American, gay, psychedelic, and other communities in New York City and Philadelphia during the late 1960s and...
recordings. Jeff Lynne
Jeff Lynne
Jeffrey "Jeff" Lynne is an English songwriter, composer, arranger, singer, multi-instrumentalist, and record producer who gained fame as the leader and sole constant member of Electric Light Orchestra and was a co-founder and member of The Traveling Wilburys together with George Harrison, Bob...
of Electric Light Orchestra
Electric Light Orchestra
Electric Light Orchestra were a British rock group from Birmingham who released eleven studio albums between 1971 and 1986 and another album in 2001. ELO were formed to accommodate Roy Wood and Jeff Lynne's desire to create modern rock and pop songs with classical overtones...
used the vocoder in several albums such as Time
Time (Electric Light Orchestra album)
Time is a concept album by Electric Light Orchestra released in 1981 through Jet Records. The album tells the story, through its songs and lyrics, about a man from the 1980's finding himself in the year 2095 and trying to come to terms with being unable to return and adjusting to his new...
(featuring the Roland VP-330 Plus MkI). ELO songs such as "Mr. Blue Sky
Mr. Blue Sky
"Mr. Blue Sky" is a song by English rock group Electric Light Orchestra, featured on the band's seventh studio album Out of the Blue . Written and produced by frontman Jeff Lynne, the song forms the fourth and final track of the "Concerto for a Rainy Day" suite, on side three of the original double...
" and "Sweet Talkin' Woman
Sweet Talkin' Woman
"Sweet Talkin' Woman" is a 1978 single by The Electric Light Orchestra from the LP Out of the Blue. Its original title was "Dead End Street", but it was changed during recording, perhaps to avoid confusion with a 1966 hit of the same title by the Kinks...
" both from Out of the Blue
Out of the Blue (Electric Light Orchestra album)
The 30th Anniversary Edition was released on February, 20th 2007 with three bonus tracks.-Personnel:ELO*Jeff Lynne – lead vocals, backing vocals, guitar, keyboards, percussion*Bev Bevan – drums, percussion, backing vocals, fire extinguisher on "Mr...
(1977) use the vocoder extensively. Featured on the album are the EMS Vocoder 2000W MkI, and the EMS Vocoder (-System) 2000 (W or B, MkI or II).
Giorgio Moroder
Giorgio Moroder
Hansjörg "Giorgio" Moroder is an Italian record producer, songwriter and performer based in Los Angeles. When in Munich in the 1970s, he started his own record label called Oasis Records, which several years later became a subdivision of Casablanca Records...
made extensive use of the vocoder on the 1975 album Einzelganger and on the 1977 album From Here to Eternity. Another example is Pink Floyd
Pink Floyd
Pink Floyd were an English rock band that achieved worldwide success with their progressive and psychedelic rock music. Their work is marked by the use of philosophical lyrics, sonic experimentation, innovative album art, and elaborate live shows. Pink Floyd are one of the most commercially...
's album Animals, where the band put the sound of a barking dog through the device. Vocoders are often used to create the sound of a robot talking, as in the Styx
Styx (band)
Styx is an American rock band that became famous for its albums from the late 1970s and early 1980s. The Chicago band is known for melding the style of prog-rock with the power of hard rock guitar, strong ballads, and elements of American musical theater....
song "Mr. Roboto
Mr. Roboto
"Mr. Roboto" is a song written by Dennis DeYoung and performed by the band Styx on their 1983 concept album Kilroy Was Here. In Canada, where they were always more popular than in their native U.S., it went to #1 on the RPM national singles chart, becoming their third single to top the charts in...
". It was also used for the introduction to the Main Street Electrical Parade
Main Street Electrical Parade
The Main Street Electrical Parade is a regularly scheduled parade, created by Bob Jani and project director Ron Miziker, famous for its long run at Disneyland at the Disneyland Resort most summers between 1972–1974, 1977–1982, and 1985-1996...
at Disneyland.
Vocoders have appeared on pop recordings from time to time ever since, most often simply as a special effect
Special effect
The illusions used in the film, television, theatre, or entertainment industries to simulate the imagined events in a story are traditionally called special effects ....
rather than a featured aspect of the work. However, many experimental electronic artists of the New Age music
New Age music
New Age music is music of various styles intended to create artistic inspiration, relaxation, and optimism. It is used by listeners for yoga, massage, meditation, and reading as a method of stress management or to create a peaceful atmosphere in their home or other environments, and is often...
genre often utilize vocoder in a more comprehensive manner in specific works, such as Jean Michel Jarre
Jean Michel Jarre
Jean Michel André Jarre is a French composer, performer and music producer. He is a pioneer in the electronic, ambient and New Age genres, and known as an organiser of outdoor spectacles of his music featuring lights, laser displays, and fireworks.Jarre was raised in Lyon by his mother and...
(on Zoolook
Zoolook
Zoolook is the fourth overall mainstream studio album by Jean Michel Jarre, and released on Disques Dreyfus in 1984. It makes extensive use of digital recording techniques and sampling. It is considered by many fans as one of Jarre's most experimental albums to date...
, 1984) and Mike Oldfield
Mike Oldfield
Michael Gordon Oldfield is an English multi-instrumentalist musician and composer, working a style that blends progressive rock, folk, ethnic or world music, classical music, electronic music, New Age, and more recently, dance. His music is often elaborate and complex in nature...
(on QE2
QE2 (album)
QE2 is the sixth record album by Mike Oldfield, released in 1980 on Virgin Records.The album contained both original Oldfield compositions as well as two cover version of pieces recorded by other bands .- Album analysis :The longest tracks on the album are "Taurus I" and the title track, "QE2",...
, 1980 and Five Miles Out
Five Miles Out
Five Miles Out is the seventh record album by Mike Oldfield, released in 1982, at a time when his music was moving away from large-scale symphonic pieces towards a more accessible pop style. It is one of the very few albums on which Oldfield sings lead vocals, as he is noted for not having any...
, 1982). There are also some artists who have made vocoders an essential part of their music, overall or during an extended phase. Examples include the German synthpop
Synthpop
Synthpop is a genre of popular music that first became prominent in the 1980s, in which the synthesizer is the dominant musical instrument. It was prefigured in the 1960s and early 1970s by the use of synthesizers in progressive rock, electronic art rock, disco and particularly the "Kraut rock" of...
group Kraftwerk
Kraftwerk
Kraftwerk is an influential electronic music band from Düsseldorf, Germany. The group was formed by Ralf Hütter and Florian Schneider in 1970, and was fronted by them until Schneider's departure in 2008...
, Stevie Wonder ["Send One Your Love", "A Seed's a Star"] and jazz/fusion keyboardist Herbie Hancock
Herbie Hancock
Herbert Jeffrey "Herbie" Hancock is an American pianist, bandleader and composer. As part of Miles Davis's "second great quintet," Hancock helped to redefine the role of a jazz rhythm section and was one of the primary architects of the "post-bop" sound...
during his late 1970s period.
In 1982 Neil Young used a Sennheiser Vocoder VSM201 on six of the nine tracks on 'Trans'.
Other voice effects
"Robot voices" became a recurring element in popular music during the 20th century. Several methods of producing variations on this effect are: the Sonovox, Talk boxTalk box
A talk box is an effects unit that allows a musician to modify the sound of a musical instrument. The musician controls the modification by lip syncing, or by changing the shape of the mouth...
, Auto-Tune
Auto-Tune
Auto-Tune is a proprietary audio processor created by Antares Audio Technologies. Auto-Tune uses a phase vocoder to correct pitch in vocal and instrumental performances. It is used to disguise off-key inaccuracies and mistakes, and has allowed singers to perform apparently perfectly tuned vocal...
,
a sample of Auto-Tune
Auto-Tune
Auto-Tune is a proprietary audio processor created by Antares Audio Technologies. Auto-Tune uses a phase vocoder to correct pitch in vocal and instrumental performances. It is used to disguise off-key inaccuracies and mistakes, and has allowed singers to perform apparently perfectly tuned vocal...
effect (a.k.a. T-Pain effect).
linear prediction vocoders, speech synthesis
Speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...
,
a sample of earlier computer based speech synthesis
Speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...
and song synthesis, by John Larry Kelly, Jr. and Louis Gerstman at Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
, using IBM 704
IBM 704
The IBM 704, the first mass-produced computer with floating point arithmetic hardware, was introduced by IBM in 1954. The 704 was significantly improved over the IBM 701 in terms of architecture as well as implementations which were not compatible with its predecessor.Changes from the 701 included...
computer. The demo song “Daisy Bell
Daisy Bell
"Daisy Bell" is a popular song with the well-known chorus "Daisy, Daisy/Give me your answer do/I'm half crazy/all for the love of you" as well as the line "...a bicycle built for two".-History:"Daisy Bell" was composed by Harry Dacre in 1892...
”, musical accompanied by Max Mathews
Max Mathews
Max Vernon Mathews was a pioneer in the world of computer music.-Biography:...
, impressed Arthur C. Clarke
Arthur C. Clarke
Sir Arthur Charles Clarke, CBE, FRAS was a British science fiction author, inventor, and futurist, famous for his short stories and novels, among them 2001: A Space Odyssey, and as a host and commentator in the British television series Mysterious World. For many years, Robert A. Heinlein,...
and later he used it in the climactic scene of screenplay for his novel 2001: A Space Odyssey.
a sample of speech synthesis
Speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...
.
ring modulation
Ring modulation
Ring modulation is a signal-processing effect in electronics, an implementation of amplitude modulation or frequency mixing, performed by multiplying two signals, where one is typically a sine-wave or another simple waveform. It is referred to as "ring" modulation because the analog circuit of...
and comb filter
Comb filter
In signal processing, a comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. The frequency response of a comb filter consists of a series of regularly spaced spikes, giving the appearance of a comb....
.
Singing guitar
In 1939, Alvino ReyAlvino Rey
Alvin McBurney , known by his stage name Alvino Rey, was an American swing era musician and pioneer, often credited as the father of the pedal steel guitar...
used a carbon throat microphone wired in such a way as to modulate his electric steel guitar sound. from
a sample of Singing guitar.
The mic, originally developed for military pilot communications, was placed on the throat of Rey's wife Luise King (one of The King Sisters
The King Sisters
The King Sisters were an American big band-era vocal quartet.-History:Born and raised in Pleasant Grove, Utah, about 35 miles south of Salt Lake City, the King Sisters originally were part of the "Driggs Family of Entertainers"."In the early 1930s sisters Luise, Maxine and Alyce formed a vocal trio...
), who stood behind a curtain and mouthed the words, along with the guitar lines. The novel-sounding combination was called "Singing Guitar", but was not developed further.
Rey also created a somewhat similar "talking" effect, by manipulating the tone controls of his Fender electric guitar, but the vocal effect was less pronounced.
Sonovox
Another early voice effect using the same principle of the throat as a filter was the Sonovox. Instead of a throat microphone modulating a guitar signal, it used small loudspeakers attached to the performer's throat. It was used in films such as A Letter to Three WivesA Letter to Three Wives
A Letter to Three Wives is a 1949 film which tells the story of a woman who mails a letter to three women, telling them she has left town with the husband of one of them. It stars Jeanne Crain, Linda Darnell, Ann Sothern, Kirk Douglas, Paul Douglas in his film debut, Jeffrey Lynn, and Thelma Ritter...
(1949), The Secret Life of Walter Mitty
The Secret Life of Walter Mitty
"The Secret Life of Walter Mitty" is a short story by James Thurber. The most famous of Thurber's stories, it first appeared in The New Yorker on March 18, 1939, and was first collected in his book My World and Welcome to It...
(1947), the voice of Casey Junior the train
Train
A train is a connected series of vehicles for rail transport that move along a track to transport cargo or passengers from one place to another place. The track usually consists of two rails, but might also be a monorail or maglev guideway.Propulsion for the train is provided by a separate...
in Dumbo
Dumbo
Dumbo is a 1941 American animated film produced by Walt Disney and released on October 23, 1941, by RKO Radio Pictures.The fourth film in the Walt Disney Animated Classics series, Dumbo is based upon the storyline written by Helen Aberson and illustrated by Harold Pearl for the prototype of a...
(1941) and The Reluctant Dragon
The Reluctant Dragon (film)
The Reluctant Dragon is a 1941 American combined live action and animated film produced by Walt Disney, directed by Alfred Werker, and released by RKO Radio Pictures on June 20, 1941...
(1941), the instruments in Rusty in Orchestraville, the piano in Sparky's Magic Piano
Sparky's Magic Piano
Sparky's Magic Piano is the second in a series of children’s audio stories featuring Sparky, an original character created for Capitol Records in 1947. Sparky is a little boy with an overactive imagination...
, and the airplane in Whizzer The Talking Airplane (1947). The Sonovox was also used in many radio station IDs produced by PAMS
PAMS
PAMS , based in Dallas, Texas, was the most famous jingle production company in American broadcasting. It produced identification packages for radio stations around the world, as well as some commercial music.-History:The company was founded by William B. Meeks, Jr. PAMS (an acronym for Production,...
of Dallas and JAM Creative Productions
JAM Creative Productions
JAM Creative Productions, Inc., is an American company that produces radio jingles, promo music for television, and commercial jingles for advertisers. It has made more radio jingles than any other jingle company and has become part of American pop culture....
. Lucille Ball
Lucille Ball
Lucille Désirée Ball was an American comedian, film, television, stage and radio actress, model, film and television executive, and star of the sitcoms I Love Lucy, The Lucy–Desi Comedy Hour, The Lucy Show, Here's Lucy and Life With Lucy...
made one of her earliest film appearances during the 1930s in a Pathé Newsreel demonstrating the Sonovox.
The Sonovox makes an even earlier appearance in the 1940 film You'll Find Out
You'll Find Out
You'll Find Out is a 1940 comedy film directed by David Butler and starring Boris Karloff. The film was nominated for an Academy Award in 1941 for Best Original Song...
starring Kay Kyser and his orchestra, from
a sample of Sonovox.
Bela Lugosi, Boris Karloff, and Peter Lorre. Lugosi uses the Sonovox to portray the voice of a dead person during a seance.
Talk box
One of the earliest uses of a talk boxTalk box
A talk box is an effects unit that allows a musician to modify the sound of a musical instrument. The musician controls the modification by lip syncing, or by changing the shape of the mouth...
appears in The Ventures
The Ventures
The Ventures is an American instrumental rock band formed in 1958 in Tacoma, Washington. Founded by Don Wilson and Bob Bogle, the group in its various incarnations has had an enduring impact on the development of music worldwide. With over 100 million records sold, the group is the best-selling...
' Christmas Album
The Ventures discography
The Ventures have released hundreds of albums beginning with Walk Don't Run . The original U.S. albums and singles are indicated by their catalog numbers and Billboard and Cashbox chart peak positions - 1960 - 1972 :- 1972 - Present :* Only Hits* The Ventures have released hundreds of albums...
, released in 1965. In the song "Silver Bells", Red Rhodes
Red Rhodes
Rhodes played pedal steel on many country rock, pop and rock albums with The Monkees, James Taylor, Seals and Crofts, The Byrds, The Carpenters and many other groups. He is most often remembered for his work with former Monkee Michael Nesmith on Nesmith's first solo albums in the early 1970s...
spoke through a talk box, distorting the phrase silver bells.
a sample of Talk box
Talk box
A talk box is an effects unit that allows a musician to modify the sound of a musical instrument. The musician controls the modification by lip syncing, or by changing the shape of the mouth...
.
Television
Vocoders are used in television production, filmmakingFilmmaking
Filmmaking is the process of making a film, from an initial story, idea, or commission, through scriptwriting, casting, shooting, directing, editing, and screening the finished product before an audience that may result in a theatrical release or television program...
and games, usually for robots or talking computers.
- The CylonsCylon (Battlestar Galactica)The Cylons are a cybernetic civilization at war with the Twelve Colonies of humanity in the Battlestar Galactica science fiction franchise, in the original 1978 and 1980 series, the 2004 reimagining, as well as the spin-off prequel series, Caprica...
from Battlestar GalacticaBattlestar Galactica (1978 TV series)Battlestar Galactica is an American science fiction television series, created by Glen A. Larson. It starred Lorne Greene, Richard Hatch and Dirk Benedict and ran for one season in 1978–79. After cancellation, its story was continued in 1980 as Galactica 1980 with Adama, Lieutenant Boomer and...
used an EMS Vocoder 2000 to create their voice-effects. The 1980 version of the Doctor WhoDoctor WhoDoctor Who is a British science fiction television programme produced by the BBC. The programme depicts the adventures of a time-travelling humanoid alien known as the Doctor who explores the universe in a sentient time machine called the TARDIS that flies through time and space, whose exterior...
theme has a section generated by a Roland SVC-350 Vocoder.
Analogue vocoder models
- Analog-Lab X-32 [32-band]
- BodeHarald BodeHarald Bode was a German engineer and pioneer in the development of electronic music instruments.- Biography :...
Model 7702 [16-band] - BV12
- DoepferDoepferDoepfer Musikelektronik GmbH is a manufacturer of audio hardware based in Gräfelfing, Germany, founded by Dieter Döpfer.The product range covers analog modular systems, MIDI controller, MIDI hardware sequencers, MIDI-to-CV/Gate/Sync Interfaces, MIDI master keyboards and special MIDI...
Modular Vocoder subsystem A-129 - Dynacord SRV66
- Electro-HarmonixElectro-HarmonixElectro-Harmonix is a New York-based company that makes high-end electronic audio processors. The company was founded by Mike Matthews in 1968. They are most famous for a series of popular guitar effects pedals introduced in the 1970s and 1990s....
Vocoder - Elektronika (Электроника) EM 26
- EMS
- EMS Vocoder 1000
- EMS Vocoder 2000 [16-band]
- EMS Vocoder 3000 [16-band]
- EMS Vocoder 5000
- Farad - Bruce HaackBruce HaackBruce Clinton Haack was a musician, composer, and pioneer of electronic music. He was born in Alberta, Canada.-From Alberta to New York :...
Custom Model - Korg VC-10Korg VC-10The Korg VC-10 is an analogue vocoder from the 1970s. Vocoding refers to voice encoding of speech and singing with musical synthesis. It gained popularity in the '70s following utilisation by bands such as Kraftwerk and ELO. The VC-10 allows basic functionality in operation and modulation of signal...
[20-band] - KraftwerkKraftwerkKraftwerk is an influential electronic music band from Düsseldorf, Germany. The group was formed by Ralf Hütter and Florian Schneider in 1970, and was fronted by them until Schneider's departure in 2008...
Custom Model (Above Photo) - Krok (Крок) 2401 Vocoder (Вокодер) [24-band]
- MAM Vocoder VF11
-
- FAT PCP-330 Procoder
-
- Next! VX-11 Vocoder
- MoogMoog MusicMoog Music is an American company based in Asheville, North Carolina which manufactures electronic musical instruments. The current Moog Music is the second company to trade under that name.-R.A. Moog Co. and the original Moog Music:...
:- R.A. MoogMoog MusicMoog Music is an American company based in Asheville, North Carolina which manufactures electronic musical instruments. The current Moog Music is the second company to trade under that name.-R.A. Moog Co. and the original Moog Music:...
Modular Vocoder [11-band ?] - Moog Modular Vocoder (spectrum encoder-decoder, 10 Band)
- Moog 16 channel Vocoder (Bode model 7702) [16-band]
- R.A. Moog
- PAiAPAiA ElectronicsPAiA Electronics, Inc. is an American synthesizer kit company that was started by John Simonton in 1967. It sells various musical electronics kits including analog synthesizers, theremins, mixers and various music production units designed by founder John Simonton, Craig Anderton, Marvin Jones,...
6710 Vocoder - RolandRoland Corporationis a Japanese manufacturer of electronic musical instruments, electronic equipment and software. It was founded by Ikutaro Kakehashi in Osaka on April 18, 1972, with ¥33 million in capital. In 2005 Roland's headquarters relocated to Hamamatsu in Shizuoka Prefecture. Today it has factories in Japan,...
SVC-350 [11-band ?] - Roland VP-330 Vocoder Plus [10-band]
- SennheiserSennheiserSennheiser electronic GmbH & Co. KG is a private German audio company specializing in the design and production of a wide range of both consumer and high fidelity products, including microphones, headphones, telephony accessories, and avionics headsets for consumer, professional, and business...
VSM 201 [10-band ?] - SiemensSiemensSiemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
Synthesizer - SyntonSynton FenixSynton was a manufacturer and distributor of high-end electronic music equipment in the Netherlands. They were one of the principal importers of music equipment from E-Mu, Ensoniq, and Fairlight in Europe...
:- Syntovox 202
- Syntovox 216 [14-band]
- Syntovox 221
- Syntovox 222
Hardware DSP vocoder models
- Access VirusAccess VirusThe Access Virus is a virtual analog synthesizer made by the German company Access Music GmbH. It was first produced in 1997 and has since been upgraded frequently, with the company releasing new models about every two years. Early models include the Virus A, Virus B, and Virus C series, each...
C Series/Virus TI Series [32-band] - Akai Professional MiniAK (Virtual Analog Synth) [40-band]
- AlesisAlesisAlesis is a company based in Cumberland, Rhode Island, that designs and markets electronic musical instruments, digital audio processors, audio mixers, digital audio interfaces, recording equipment, drum machines, professional audio and electronic percussion products...
:- Akira
- Alesis IonAlesis IonThe Alesis Ion is an analog modeling synthesizer. It was presented to the public on the Summer NAMM of 2002 . Unlike the Alesis Andromeda, Alesis's analog synthesizer, its sounds are synthesized using DSP chips to mimic the sound of analog audio circuitry and components.-Features:The Ion has...
[40-band] - Metavox
- Alesis Micron [40-band]
- BehringerBehringerBehringer is an audio equipment company founded by Uli Behringer in 1989, in Willich, Germany. Behringer was listed as the 14th largest manufacturer of music products in 2007. Behringer is a multi-national group of companies, with direct marketing presence in 10 countries or territories and a...
2024 DSP Virtualizer Pro - Clavia Nord ModularClavia Nord ModularThe Clavia Nord Modular series is a line of synthesizers produced by Clavia, a Swedish digital synthesizer manufacturer. The Nord Modular series, in common with their sister range the Nord Lead series, are analogue modelling synthesizers, producing sounds which approximate those produced by...
- DigiTech:
- Talker
- S100/S200
- StudioQuad 4
- Electro-HarmonixElectro-HarmonixElectro-Harmonix is a New York-based company that makes high-end electronic audio processors. The company was founded by Mike Matthews in 1968. They are most famous for a series of popular guitar effects pedals introduced in the 1970s and 1990s....
:- Iron Lung
- V256 Vocoder
- Voice Box (Harmony Machine and Vocoder)
- EnsoniqEnsoniqEnsoniq Corp. was an American electronics manufacturer, best known throughout the mid 1980s and 1990s for its musical instruments, principally samplers and synthesizers.- Company history :...
FIZMO - EventideEventide, IncEventide is an audio & broadcast, communications, and avionics company in the United States whose audio division manufactures digital audio processors and DSP software, and guitar effects...
Harmonizer- SP2016
- H3000
- H7600
- H8000
- Orvillle
- KorgKorgis a Japanese multinational corporation that manufactures electronic musical instruments, audio processors and guitar pedals, recording equipment, and electronic tuners...
:- DVP-1 Digital Voice Processor
- microKorg
- MS2000Korg MS2000The Korg MS2000 is a virtual analog synthesizer produced by the Japanese electronic musical instrument manufacturer Korg.-History and features:...
[16-band] - R3
- RadiasKorg RADIASKorg RADIAS is a virtual analog synthesizer, released by KORG corp. in 2006.RADIAS' MMT engine was based on Korg's Oasys AL-1 synthesizer module, providing for several different synthesis methods, two of which may be combined in a single voice e.g. Phase Distortion Synthesis can be combined with...
- WavestationKorg WavestationThe Korg Wavestation is a vector synthesis synthesizer first produced in the early 1990s and later re-released as a software synthesizer in 2004. Its primary innovation was Wave Sequencing, a method of multi-timbral sound generation in which different PCM waveform data are played successively,...
- NovationNovation Digital Music SystemsNovation Digital Music Systems Ltd. is a UK musical equipment manufacturer. Founded in 1992 as Novation Electronic Music Systems, the company specialises in MIDI controllers and analog modeling synthesizers, which they have manufactured in China....
:- A-station (Analog Modeling Synthesizer Vocoder)
- K-Station KS4 / KS5 / KS Rack [16-band]
- Nova [40-band]
- QuasimidiQuasimidiQuasimidi Musikelektronik GmbH was a German synthesizer manufacturer. It was founded in 1987 by Friedhelm Haas and Jörg Reichstein. It was originally based in Kirchhain, but moved to Rauschenberg in 1998...
Sirius - RolandRoland Corporationis a Japanese manufacturer of electronic musical instruments, electronic equipment and software. It was founded by Ikutaro Kakehashi in Osaka on April 18, 1972, with ¥33 million in capital. In 2005 Roland's headquarters relocated to Hamamatsu in Shizuoka Prefecture. Today it has factories in Japan,...
:- JP-8080Roland JP-8000The Roland JP-8000 is an analog modeling synthesizer released by the Roland Corporation in 1997.- Overview :The Roland JP-8000 was released in early 1997 to compete with the other analog modeling synthesizers of the period such as the Access Virus, Clavia Nord Lead the Korg MS2000 and the Yamaha AN1x...
[12-band] - Juno-Stage [10-band]
- SP-808 [10-band]
- VP-550
- VP-770
- VP-7
- JP-8080
- Symbolic Sound KymaKyma (sound design language)Kyma is a visual programming language for sound design used by musicians, researchers, and sound designers. In Kyma, a user programs a multiprocessor DSP by graphically connecting modules on the screen of a Macintosh or Windows computer.-Background:...
/Pacarana - TC-HeliconTC-HeliconTC-Helicon is a Canadian audio equipment manufacturer, a subsidiary of Danish company TC Electronic. TC-Helicon focuses on vocal harmonizers, pitch correction, monitor speakers, and other products for vocalists....
VoiceTone Synth (HardTune & Vocoder Pedal) - WaldorfWaldorf MusicWaldorf Music AG is a German synthesizer company. It was founded on 1 January 2003 to take over the actual business of the Waldorf Electronics GmbH which had become insolvent. Waldorf is best known for its Microwave wavetable synthesizer and Q virtual analogue synthesizer lines.- History :Waldorf...
Q - Yamaha PLG100VH
- Yamaha MOTIF XS/XF
- Zoom Studio 1201
Software vocoder models
- Ableton LiveAbleton LiveAbleton Live is a loop-based software music sequencer and DAW for Mac OS and Windows by Ableton. The latest major release of Live, Version 8, was released in April 2009. In contrast to many other software sequencers, Live is designed to be an instrument for live performances as well as a tool for...
Vocoder effect (built-in since version 8.x) - ArturiaArturiaArturia is a software company located in Grenoble, France and founded in 1999 by Frédéric Brun and Gilles Pommereuil, both INPG-qualified engineers. The company's focus is on the development of electronic music software and tools - primarily emulation of vintage analog synthesizers...
Vocoder - Eiosis ELS Vocoder (software reproduction of EMS Vocoder 5000)
- Image-Line Fruity Vocoder
- Native InstrumentsNative InstrumentsNative Instruments is a technology company that develops software and hardware for music production and DJing. The company has originally been identified mostly with software instruments, but has also expanded to various other music equipment segments in recent years.Current products of Native...
Vokator - Propellerheads Reason BV-512 [4 to 512-band]
- ProsoniqProsoniqShort for "Prosoniq Products Software", developer and license provider for tools in the audio and music industry, mostly known for their sonicWORX, OrangeVocoder, TimeFactory and the Hartmann Neuron synthesizer products.-Description:...
OrangeVocoder - WaldorfWaldorf MusicWaldorf Music AG is a German synthesizer company. It was founded on 1 January 2003 to take over the actual business of the Waldorf Electronics GmbH which had become insolvent. Waldorf is best known for its Microwave wavetable synthesizer and Q virtual analogue synthesizer lines.- History :Waldorf...
Lector - WavesWaves AudioWaves Audio Ltd. is a developer and supplier of professional audio signal processing technologies and audio effects, used in recording, mixing, mastering, post production, surround, live, and broadcast sound...
Morphoder
See also
- Homer DudleyHomer DudleyHomer W. Dudley was a pioneering electronic and acoustic engineer who created the first electronic voice synthesizer for Bell Labs in the 1930s and led the development of a method of sending secure voice transmissions during World War Two....
- Werner Meyer-EpplerWerner Meyer-EpplerWerner Meyer-Eppler , was a German physicist, experimental acoustician, phoneticist, and information theorist....
- Audio timescale-pitch modificationAudio timescale-pitch modificationTime stretching is the process of changing the speed or duration of an audio signal without affecting its pitch.Pitch scaling or pitch shifting is the opposite: the process of changing the pitch without affecting the speed...
- Phase vocoderPhase vocoderA phase vocoder is a type of vocoder which can scale both the frequency and time domains of audio signals by using phase information. The computer algorithm allows frequency-domain modifications to a digital sound file .At the heart of the phase vocoder is the short-time Fourier transform ,...
- Silent speech interfaceSilent speech interfaceSilent speech interface is a device that allows speech communication without using the sound made when people vocalize their speech sounds. As such it is a type of electronic lip reading. It works by the computer identifying the phonemes that an individual pronounces from nonauditory sources of...
External links
- Moog
- Next! VX-11 Vocoder
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- FAT PCP-330 Procoder
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