A music sequencer (or simply sequencer) is a device or application software that can record, edit, or play back music, by handling note and performance information in several forms, typically MIDI or CV/Gate, and possibly audio and automation data for DAWs and plug-ins.
Types of music sequencers
As mentioned above, music sequencers are often categorized by handling data types, as following:
Also, music sequencer can be categorized by its construction and supporting modes.
- Realtime sequencer (realtime recording mode)
A realtime sequencer on the synthesizer
- Realtime sequencer records the musical notes in real-time as on audio recorders, and play-back musical notes with designated tempo, quantizations, and pitch. For editing, usually "punch in/punch out" feature originated in the tape recording is provided, although it requires enough skills to obtain desired result. For detailed editing, possibly another visual editing modes under graphical user interface may be more suitable. Anyway, this mode provides usability similar to the audio recorder already familiarized by musicians, and it is widely supported on software sequencer, DAW, and built-in hardware sequencers.
- Analog sequencer
An analog sequencer
- Analog sequencers are typically implemented with analog electronics, and play the musical notes designated by a series of knobs or sliders corresponding to each musical note (step). It is designed for both composition and live performance; users can anytime change the musical notes without regarding recording mode. And also possibly, the time-interval between each musical note (length of each step) can be independently adjustable. Typically, analog sequencer is used to generate the repeated minimalistic phrases which is reminiscent of Tangerine Dream, Giorgio Moroder or trance music.
- Step sequencer (step recording mode)
A step sequencer on the drum machine
- On the step sequencers, musical notes are rounded into the steps with equal time-interval, and users can enter each musical note without exact timing. Instead, the timing and duration are designated in several ways:
- On the bass machines: entering order of steps, and selection of length-buttons.
- On the drum machines: selection of column of timing-buttons
- On several home keyboards: individual timing recording in realtime, using trigger-buttons
- In general, step mode, along with semi-realtime mode, is often supported on the analog drum machines, bass machines and several groove machines,
- Software sequencer
- Software sequencer is a class of application software providing a functionality of music sequencer, and often provided as a feature of the DAW or the integrated music authoring environments. The features provided are wide variety depend on each software; even an analog sequencer can be simulated on it. The user may control the software sequencer either by using the graphical user interfaces or a specialized input devices, such as a MIDI controller.
Typical features on software sequencers
With the advent of MIDI and particularly Atari ST in 1980s, programmers were able to write software that could record and play back the notes played by a musician. Unlike the early sequencers used to play mechanical sounding sequence with exactly equal length, the new ones recorded and played back expressive performances by real musicians. These were typically used to control external synthesizers, especially rackmounted sound modules as it was no longer necessary for each synthesizer to have its own keyboard.
As the technology matured, sequencers gained more features, and integrated the ability to record multitrack audio. Sequencers mainly used for audio are often called digital audio workstations (or DAWs).
Many modern sequencers can also control virtual instruments implemented as software plug-ins, allowing musicians to replace separate synthesizers with software equivalents.
Today the term "sequencer" is often used to describe software. However, hardware sequencers still exist. Workstation keyboards have their own proprietary built-in MIDI sequencers. Drum machines and some older synthesizers have their own step sequencer built in. There are still also standalone hardware MIDI sequencers, although the market demand for those has diminished greatly due to the greater feature set of their software counterparts.
The early music sequencers had appeared in the form of various automatic musical instruments, including music boxes, mechanical organs, player pianos, Orchestrions, etc. For example, authoring process of piano roll fits the definition of music sequencer: composers record their music composition on the piano rolls, then specialists edit the rolls as the preparation before mass duplication, and finally consumers play back the music on their player pianos.
The origin of automatic musical instruments seems considerably old. As early as 9th century, Persian inventors Banū Mūsā brothers invented hydropowered organ using exchangeable cylinders with pins, and also automatic flute player using steam power, as described on their Book of Ingenious Devices. In 14th century, rotating cylinder with pins were used to play carillon in Flanders, and at least in 15th century, barrel organs were seen in the Netherlands.
In 19th century, as the results of Industrial Revolution, various automatic musical instruments were invented, for examples: music box, barrel organ and barrel piano using barrel / cylinder with pins or metal disc with punched holes; or mechanical organ, player piano and orchestrion using book music / music rolls (piano rolls) with punched holes, etc. These instruments were widely spread as the popular entertainment devices before the inventions of phonograph, radio, and sound film. Amongst of all, especially the punched tape media had been long lived until mid-20th century: earliest programmable music synthesizers including RCA Mark II Sound Synthesizer in 1957, and Siemens Synthesizer in 1959, were also controlled via punch tapes similar to piano rolls.
Another inventions were came from sound film technology. The drawn sound technique which appeared in the late 1920s, is notable as a precursor of today's intuitive graphical user interfaces. On this technique, notes and various sound parameters were controlled by hand-drawn waves on the films, resembling piano rolls or strip charts on the modern sequencers/DAWs. It was often utilized on early experiments of electronic music, including Variophone developed by Yevgeny Sholpo in 1930, and Oramics designed by Daphne Oram in 1957, etc.
During 1940s–1960s, Raymond Scott, an American composer of electronic music have invented various kind of music sequencers for his electric compositions. The "Wall of Sound", once covered on the wall of his studio in New York during 1940s–1950s, was a electro-mechanical sequencer to produce rhythmic patterns, consisting with stepping relays (used on dial pulse telephone exchange), solenoids, control switches, and tone circuits with 16 individual oscillators. Later, Robert Moog explained it “the whole room would go 'clack - clack - clack', and the sounds would come out all over the place”. The Circle Machine, developed in 1959, had dimmer bulbs arranged in a ring, and a rotating arm with photocell scanning over the ring, to generate arbitrary waveform. Also, the rotating speed of arm was controlled via brightness of lights, and as the results, arbitrary rhythms were generated. And relatively well known Clavivox, developed since 1952, was a kind of keyboard synthesizer with sequencer. On its prototype, a theremin manufactured by young Robert Moog was utilized to enable portamento over 3-octave range, and on later version, it was replaced by a pair of photographic film and photocell for controlling the pitch by voltage.
One of the earliest commercially available analog sequencer (front) on Buchla
Moog sequencer module (left, probably added after 1968) on Moog Modular
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one of the earliest programmable drum machine
The step sequencers played rigid patterns of notes using a grid of (usually) 16 buttons, or steps, each step being 1/16 of a measure. These patterns of notes were then chained together to form longer compositions. Sequencers of this kind are still in use, mostly built into drum machines and grooveboxes. They are monophonic by nature, although some are multi-timbral, meaning that they can control several different sounds but only play one note on each of those sounds.
Max Mathews playing a violin connected to the GROOVE system (1970)
Main article: Computer music
On the other hand, software sequencers were continuously utilized since 1950s, in the context of computer music, including computer played music (software sequencer), computer composed music (music synthesis), and computer sound generation (sound synthesis). In June 1951, first computer music Colonel Bogey was played on CSIRAC, Australia's first digital computer. In 1956, Lejaren Hiller at University of Illinois at Urbana-Champaign wrote an earliest program for computer music composition on ILLIAC, and collaborated on the first piece, Illiac Suite for String Quartet, with Leonard Issaction. In 1957, Max Mathews at Bell Labs wrote MUSIC, a first widely-used program for sound generation, and 17 second composition was performed by the IBM 704 computer. Since then, computer music were mainly researched on the expensive mainframe computers on the computer centers, until 1970s when minicomputers and following microcomputers went into practice on this field.
In 1971, Electronic Music Studios (EMS) released one of the first digital sequencer products as a module of Synthi 100, and separated products Synthi Sequencer series. After then, Oberheim released DS-2 Digital Sequencer in 1974, and Sequential Circuits released Model 800 in 1977 
Also in 1977, Roland Corporation released their first microcomputer-based digital sequencer, MC-8 Microcomposer, also called computer music composer by Roland. It equipped keypad to enter note in numeric code, 16KB RAM for maximum 5200 notes (large enough at that time), and polyphony function which allocates multiple pitch CV into single Gate. The earliest known user was Yellow Magic Orchestra in 1978, an electronic music group.
In 1975, New England Digital (NED) released ABLE computer (microcomputer) as a dedicated data processing unit for Dartmouth Digital Synthesizer (1973), and based on it, later Synclavier series were developed. The Synclavier I, released in September 1977, was one of the earliest digital music workstation product with multitrack sequencer. Synclavier series evolved throughout late 1970s–mid 1980s, and they also established integration of digital-audio and music-sequencer, on their Direct-to-Disk option in 1984, and later Tapeless Studio system.
In 1980, renewed Fairlight CMI Series II with its sequencer, “Page R”, combined step sequencing with sample playback. In 1987, this led to the development of similar software sequencers of this kind, called Trackers, which became popular in the 1980s and 1990s as simple sequencers for creating computer game music, and are yet popular in the Demoscene and Chiptunes.
Visual timeline of rhythm sequencers
Many synthesizers, and by definition all music workstations, groove machines and drum machines, contain their own sequencers.
Followings are specifically designed to function primarily as the music sequencers:
Rotating object with pins or holes
- Barrel or cylinder with pins (since 9th or 14th century) utilized on barrel organs, carillons, music boxes
- Metal disc with punched holes (late 1800s) — utilized on several music boxes such as Polyphon, Regina, Symphonion, Ariston, Graphonola (early version), etc.
(1957) controls sounds by graphics on films
- Variophone (1930) by Evgeny Sholpo — on earliest version, hand drawn waves on film or disc were used to synthesize sound, and later versions were promised to experiment on musical intonations and temporal characteristics of live music performance, however not finished. Variophone is often referred as a forerunner of drawn sound system including ANS synthesizer and Oramics.
- Composer-Tron (1953) by Osmond Kendal — rhythmical sequences were controlled via marking cue on film, while timbre of note or envelope-shape of sound were defined via hand drawn shapes on a surface of CRT input device, drawn with a grease pencil.
- ANS synthesizer (1938-1958) by Evgeny Murzin — An earliest realtime additive synthesizer using 720 microtonal sine waves (1/6 semitones × 10 octaves) generated by five glas discs. Composers could control time evolution of amplitudes of each microtones via scratches on glass plate user interface covered with black mastic.
- Oramics (1957) by Daphne Oram — hand drawn contours on a set of ten sprocketed synchronized strips of 35 film were used to control various parameters of monophonic sound generator (frequency, timbre, amplitude and duration). Polyphonic sounds were obtained using multitrack recording technique.
- Analog sequencers with CV/Gate interface
Moog 960 Sequential Controller and 962 Sequential Switch
- Buchla 100's sequencer modules (1964/1966–) — One of the earliest analog sequencer on the modular synthesizer era since 1960. Later, Robert Moog admired Buchla's unique works including it.
- Moog 960 Sequential Controller / 961 Interface  / 962 Sequential Switch (c.1968)
- modules for the Moog modular synthesizer system, a popular analog sequencer following earliest Buchla sequencer.
Analog-style step sequencers
- Analog-style MIDI step sequencers
- Since the analog synthesizer revivals in 1990s, newly designed MIDI sequencers with a series of knobs or slider similar to analog sequencer have been appeared. These often equip CV/Gate and DIN sync interface along with MIDI, and even the patch memory for multiple sequence patterns and possibly song sequence. These analog-digital hybrid machines are often called Analog-style MIDI step sequencer or MIDI analog sequencer, etc.
- Analog-style MIDI pattern sequencers
- Several machines also provide the song mode to play the sequence of memoried patterns in specified order, as on drum machine.
Step sequencers (supported on)
- Typical step sequencers are integrated on drum machines, bass machines, groove machines, music production machines, and these software versions. Often, these also support the semi-realtime recording mode, too.
- MFB Step 64 — Standalone step sequencer dedicated for drum patterns (16steps/4tracks or 64steps/1tracks, 118program×4banks, 16song sequences, each with up to 128 sequences)
- Embedded self-contained step sequencers
- Several tiny keyboards provide a step sequencer combined with realtime recording mode dedicated for timings:
- Casio VL-Tone VL-1 (1979), Casiotone MT-70 (c.1984), Sampletone SK-1 (1986), etc — Timings of musical notes stored on the step sequencer, can be designated by the two triger buttons labeled "One Key Play", arround the right hand position.
- Embedded CV/Gate step sequencers
- Several machines have white & black chromatic keypads, to enter the musical phrases.
- Embedded MIDI step sequencers
- Groovebox-type machines with white & black chromatic keypads, often support step recording mode along with realtime recording mode:
- Other groovebox-type machines (including several music production machines) also often support step recording mode, of course:
- Button-grid-style step sequencers
- Recently emerging button-grid-style interfaces/instruments are naturally support step sequence. On these machines, one axis on grid means musical scale, and another axis means timing of notes.
- In addition, newly designed hardware MIDI sequencers equipping a series of knobs/sliders similar to analog sequencers, are appeared. For details, see #Analog-style MIDI step sequencers.
- Also often support Gate clock and DIN sync interfaces.
- Open Source
- Proprietary digital interfaces (pre MIDI era)
- Standalone MIDI sequencers
- MIDI phrase sequencers
- Embedded MIDI sequencers
- Accompaniment machines
Software sequencers / DAWs with sequencing features
- Not categorized yet
- Multitrack hard disk recorders
- Ardour - Linux, Mac OS X, FreeBSD (Note: No sequence feature found)
- Not categorized yet
- Realtime orchestral accompaniments
- Sinfonia , from Realtime Music Solutions (Note: It seems not the sequencer)
- Hard Disk recorder solutions for MIDI sequencers
- WinAudio from Zadok Audio & Media Products
- ^ The term "audio sequencer" seems to be relatively new expression and seems to be not clearly defined, yet. For example, "DAW integrated with MIDI sequencer" is often referred as "Audio and MIDI sequencer". However, in this usage, the term "audio sequencer" is just a synonym for the "DAW", and beyond the scope of this article. In that case, please check Digital audio workstation.
- ^ "Cubase 6 screenshot licensed under CC-BY-SA-3.0". Steinberg Media Technologies GmbH. http://www.steinberg.net/en/landing_pages/c6_creative_commons.
- ^ Fowler, Charles B. (October 1967). "The Museum of Music: A History of Mechanical Instruments". Music Educators Journal (Music Educators Journal) 54 (2): 45–49. doi:10.2307/3391092. JSTOR 3391092.
- ^ Koetsier, Teun (2001). "On the prehistory of programmable machines: musical automata, looms, calculators". Mechanism and Machine Theory (Elsevier) 36 (5): 589–603. doi:10.1016/S0094-114X(01)00005-2.
- ^ Banu Musa (authors) (1979). Donald Routledge Hill (translator). ed. The book of ingenious devices (Kitāb al-ḥiyal). Springer. pp. 76–7. ISBN 9027708339.
- ^ Chisholm, Hugh, ed. (1911). "Barrel-organ". Encyclopædia Britannica (11th ed.). Cambridge University Press.
- ^ "The RCA Synthesiser". 120 Years of Electronic Music. http://120years.net/machines/rca/. — (PDF version is available])
- ^ a b "Das Siemens-Studio für elektronische Musik von Alexander Schaaf und Helmut Klein" (in Deutsch). Deutsches Museum. http://www.deutsches-museum.de/sammlungen/ausgewaehlte-objekte/meisterwerke-vi/siemens-studio/.
- ^ a b "Wall of Sound (sequencer)". RaymondScott.com. http://raymondscott.com/1946.htm.
- ^ a b Robert Moog. "Memories of Raymond Scott". RaymondScott.com. http://raymondscott.com/moog.html.
- ^ a b "Circle Machine". RaymondScott.com. http://raymondscott.com/circle.html. — includes 2 sound files: Raymond Scott's demonstration, and commercial soundtrack for new batteries of Ford Motors.
- ^ a b Holmes, Thom (2008). Electronic and experimental music: technology, music, and culture. Taylor & Francis. p. 222. ISBN 978-0-415-95781-6. "Moog admired Buchla's work, recently stating that Buchla designed a system not only for “making new sounds but [for] making textures out of these sounds by specifying when these sounds could change and how regular those change would be.”"
- ^ "EKO Computerhythm (1972)". Jarrography - The ultimate Jean Michel Jarre discography. http://www.jarrography.free.fr/details_equipement_audio.php?id_equip=117.
- ^ "EKO Computerhythm". SynthMaster.de. http://www.synthmaster.de/ekodrum.htm.
- ^ "Multivox International" (in Germany). SYNRISE. Archived from the original on 2003-04-20. http://web.archive.org/web/20030420170643/http://www.synrise.de/docs/types/f/firstman.htm.
- ^ "CSIRAC: Australia's first computer". http://www.csiro.au/science/ps4f.html. Retrieved 2007-12-21.
- ^ Fildes, Jonathan (2008-06-17). "'Oldest' computer music unveiled". BBC News Online. http://news.bbc.co.uk/1/hi/technology/7458479.stm. Retrieved 2008-06-18. — another oldest known recording of computer realized music played by the Ferranti Mark 1, captured by BBC in Autumn, 1951; the songs Baa Baa Black Sheep and In the Mood.
- ^ Hiller, Lejaren (Winter 1981). "Composing with Computer: A Progress Report". Computer Music Journal 5 (Winter 1981).
also available in Curtis Roads, ed. The Music Machine: Selected Readings from Computer Music Journal. MIT Press (1989/1992). pp. 75. ISBN 978-0-262-68078-3.
- ^ Hinton, Graham (2001). "Synthi 100 (1971, formerly Digitana, aka the Delaware)". Electronic Music Studios (Cornwall). http://www.ems-synthi.demon.co.uk/emsprods.html#synthi100.
- ^ Hinton, Graham (2001). "Synthi Sequencer 256 (1971, formerly Synthi Moog Sequencer)". Electronic Music Studios (Cornwall). http://www.ems-synthi.demon.co.uk/emsprods.html#seq256.
- ^ J.Michmerhuizen (Boston School of Electronic Music); Thomas E. Oberheim (Oberheim Electronics) (June 1974). DS-2 Digital Sequencer Instruction and Service Manual. http://www.cem3374.com/docs/Manuals/Oberheim/DS2_O&SM.pdf.
- ^ "Model 800 Sequencer". SynthMuseum.com. http://www.synthmuseum.com/sequ/seqseq80001.html.
- ^ Russ, Martin (2008). Sound Synthesis and Sampling. Focal Press. p. 346. ISBN 0240521056. http://books.google.co.uk/books?id=_D2cTt5DPmEC&pg=PA346. Retrieved 21 June 2011.
- ^ Gordon Reid (Nov. 2004). "The History Of Roland Part 1: 1930-1978". Sound On Sound. http://www.soundonsound.com/sos/nov04/articles/roland.htm. Retrieved 2011-06-19.
- ^ Yellow Magic Orchestra — Yellow Magic Orchestra at Discogs
- ^ "Synclavier Early History". Synclavier European Services. http://www.500sound.com/synclavierhistory.html.
- ^ Joel Chadabe (May 1, 2001). "The Electronic Century Part IV: The Seeds of the Future". Electronic Musician. http://emusician.com/tutorials/electronic_century4/. "In September 1977, I bought the first Synclavier, although mine came without the special keyboard and control panel ... (see Fig. 1 on the page)."
- ^ "The Composer-Tron (1953)". 120years.net. http://120years.net/machines/composertron/.
- ^ "Daphne Oram and 'Oramics' (1959)". 120 Years of Electronic Music. http://120years.net/machines/oramics/index.html.
- ^ US patent 3,207,835, Howard E. Holman and Joseph H. Hearne (Wurlitzer Company), "Rhythm Device", issued 1965-09-21
- ^ "Moog 960 Sequential Controller". MoogArchives.com. http://moogarchives.com/m960.htm. — 3×8-step sequencer module
- ^ "Moog 961 Interface". MoogArchives.com. http://moogarchives.com/m961.htm. — interface module to convert several signal types including audio input, V-trigger (CV), and S-trigger (short-to-ground trigger for Envelope Controller)
- ^ "Moog 962 Sequential Switch". MoogArchives.com. http://moogarchives.com/m962.htm. — switching module for 960 to convert 3x8-step sequence into 1x24-step sequence, etc.
- ^ "Synthesizer 2C with optional 960 and 961 - 1968 Modular System "Synthesizer 2"". MoogArchives.com. http://moogarchives.com/mod6802.htm. — On the MoogArchives.com, the photograph with caption "Synthesizer 2C with optional 960 and 961" on this page seems to be the earliest record of Moog's sequencer module.
- ^ MFB-URZWERG, MFB Musik Elektronik, http://www.mfberlin.de/Produkte/Musikelektronik/Urzwerg/Urzwerge/urzwerge.html
- ^ MFB-URZWERG Pro, MFB Musik Elektronik, http://www.mfberlin.de/Produkte/Musikelektronik/Urzwerg_Pro/Urzwerg_Proe/urzwerg_proe.html
- ^ Roland EF-303 Groove Effects - Owner's manual, Roland Corporation, pp. 48, 53, 54, http://media.rolandus.com/manuals/EF-303_OM.pdf
- ^ Sequencer MFB-STEP64, MFB Musik Elektronik, http://www.mfberlin.de/Produkte/Musikelektronik/MFB-STEP64/MFB-STEP64_e/mfb-step64_e.html
- ^ "SM0600 Project - A Digital Sequencer - Rebuilding the Roland CSQ-700". Emulator Archive. http://www.emulatorarchive.com/AM/AMProjects/CSQ600/csq600.html.
- ^ Brandon Amison (17 Jul. 1999). "Yaking Cat Music Studios QAQA answers - Subject:0033 Re:Clothing ETC.". Yaking Cat Music Studios (Synclavier Assistance). http://home.earthlink.net/~yaking/html/answers/0033.html.
- ^ Furia, Steve De (1986). The MIDI implementation book. Third Earth Pub. p. 25. ISBN 978-0-88188-558-3. — MIDI Implementation Chart of Synclavier MIDI Option v0.9 in 1985.
- ^ Williams, Tonny (January 24, 1984), Rhodes Keyboards Instruments Chroma Computer Interface Model 1611 Rev 5 – Sequencer Manual, CBS Inc., http://www.rhodeschroma.com/content/manuals/sequencermanual.pdf
- ^ "Survey report on trends in electronic documents" (in Japanese). Japan Electronics and Information Technology Industries Association (JEITA). Archived from the original on June 2003. http://n-bz.sakura.ne.jp/around-the-music/essays/dtm-1sub.htm.
- ^ "Cool machines - Yamaha YIS PU-I-20" (in Japanese). http://www.geocities.jp/ahirudanna/zatsubun06.html. — a home automation system in 1982. System integration diagram is shown at the bottom of page.
- ^ "AM MSQ700 Nexus - MIDI Sequencer". Emulator Archive. http://www.emulatorarchive.com/AM/AMProjects/MSQ700/msq700.html.