In sound and music, an envelope describes how a sound changes over time. It may relate to elements such as amplitude (volume), filters (frequencies) or pitch.[ citation needed ] For example, a piano key, when struck and held, creates a near-immediate initial sound which gradually decreases in volume to zero.
Envelope generators, which allow users to control the different stages of a sound, are common features of synthesizers, samplers, and other electronic musical instruments. The most common form of envelope generator is controlled with four parameters: attack, decay, sustain and release (ADSR).
The Hammond Novachord in 1938 uses an early implementation of an ADSR envelope. A seven-position rotary knob set preset ADS parameter for all 72 notes; a pedal controls the release.
The envelope generator was created by the American engineer Robert Moog in the 1960s. While experimenting with the first Moog synthesizers, composer Herbert Deutsch suggested Moog find a way to articulate the instrument so notes did not simply trigger on and off. Moog wired a doorbell button to the synthesizer and used a capacitor to store and slowly release voltage produced from hitting a key. He refined the design to remove the need to push a separate button with every key press, with two switches on every key: one to produce the control voltage and the other to trigger the envelope generator.The envelope generator became a standard feature of synthesizers.
Following discussions with engineer and composer Vladimir Ussachevsky (then head of the Columbia-Princeton Electronic Music Center) in 1965, Moog developed a new envelope module whose functions were described in f T1 (attack time), T2 (initial decay time), ESUS (sustain level), and T3 (final decay time). These were later simplified to the modern ADSR form (Attack time, Decay time, Sustain level, Release time) by ARP.
The most common kind of envelope generator has four stages: attack, decay, sustain, and release (ADSR).
While, attack, decay, and release refer to time, sustain refers to level.
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Some electronic musical instruments can invert the ADSR envelope, reversing the behavior of the normal ADSR envelope. During the attack phase, the modulated sound parameter fades from the maximum amplitude to zero then, during the decay phase, rises to the value specified by the sustain parameter. After the key has been released the sound parameter rises from sustain amplitude back to maximum amplitude.
Some envelopes, such as that of the Korg MS-20, have an extra parameter, hold. This holds notes at the sustain level for a fixed length of time before decaying. The General Instruments AY-3-8912 sound chip includes only a hold time parameter; the sustain level is not programmable.
Another common variation in the same vein is the AHDSR (attack, hold, decay, sustain, release) envelope, in which the "hold" parameter controls how long the envelope stays at full volume before entering the decay phase. Multiple attack, decay and release settings may be found on more sophisticated models.
Certain synthesizers also allow for a delay parameter before the attack. Modern synthesizers, such as the Prophet '08, have DADSR (delay, attack, decay, sustain, release) envelopes. The delay setting determines the length of silence between hitting a note and the attack. Some software synthesizers, such as Image-Line's 3xOSC (included with their DAW FL Studio) have DAHDSR (delay, attack, hold, decay, sustain, release) envelopes.
A common feature on many synthesizers is an AD envelope (attack and decay only). This can be used to control e.g. the pitch of one oscillator, which in turn may be synchronized with another oscillator by oscillator sync.
Modular synthesizers are synthesizers composed of separate modules of different functions. The modules can be connected together with patch cords, a matrix patching system, or switches by the user to create a patch. The output (voltages) from the modules may function as (audio) signals, control voltages, or logic/timing conditions. Typical modules are oscillators, filters (spectrum), amplifiers/gates (amplitude) and Envelope generators.
The ARP Odyssey is an analog synthesizer introduced in 1972. Responding to pressure from Moog Music to create a portable, affordable "performance" synthesizer, ARP Instruments, Inc. scaled down its ARP 2600 synthesizer and created the Odyssey, which became their best-selling synthesizer model.
The Realistic Concertmate MG-1 is an analog synthesizer manufactured by Moog Music in 1981 and sold by Radio Shack from 1982 to 1983 under their "Realistic" brand name. It was produced without some standard Moog features, such as pitch and modulation wheels, as a cost-cutting measure aimed at achieving a lower price for the consumer market. The synthesizer also featured a pair of pass-through RCA jacks, which allowed users to mix radio or records into the final live synthesized sound output.
The Moog synthesizer is a synthesizer developed by the American engineer Robert Moog. Moog debuted it in 1964, and Moog's company R.A. Moog Co. produced numerous models from 1965 to 1980. It was the first commercial synthesizer, and is credited with creating the analog synthesizer as it is known today.
The Novachord is often considered to be the world's first commercial polyphonic synthesizer. All-electronic, incorporating many circuit and control elements found in modern synthesizers, and using subtractive synthesis to generate tones, it was designed by John M. Hanert, Laurens Hammond and C. N. Williams, and was manufactured by the Hammond company. Only 1,069 Novachords were built over a period from 1939 to 1942. It was one of very few electronic products released by Hammond that was not intended to emulate the sound of an organ.
The Voyetra-8 (Voyetra-Eight) is an eight voice polyphonic analog synthesizer. Released in 1982 by Octave-Plateau Electronics, it was one of the first analog programmable synthesizers to be rack-mountable and remains one of the most flexible digitally controlled analog synthesizers.
The Moog model 2090 Micromoog is a monophonic analog synthesizer produced by Moog Music from 1975–79.
The Korg Polysix(PS-6) is a six-voice programmable polyphonic analog synthesizer released by Korg in 1981.
The Korg MS2000 is a virtual analog synthesizer produced by the Japanese electronic musical instrument manufacturer Korg.
The Doepfer A-100 is an analog modular synthesizer system introduced by German audio manufacturer Doepfer in 1995. Although it only had 10 modules at time of release, it currently has more than 120 modules plus several different enclosures and accessories.
The Oberheim OB•12 is a Virtual Analog synthesizer, designed and realised by the Italian musical instrument manufacturer Viscount, in production between 2000 and 2005.
The ARP Omni was a polyphonic analog synthesizer manufactured by ARP Instruments, Inc.
A synthesizer is an electronic musical instrument that generates audio signals. Synthesizers generate audio through methods including subtractive synthesis, additive synthesis, and frequency modulation synthesis. These sounds may be shaped and modulated by components such as filters, envelopes, and low-frequency oscillators. Synthesizers are typically played with keyboards or controlled by sequencers, software, or other instruments, often via MIDI.
The Evolver is an analog-digital hybrid synthesizer designed by Dave Smith and manufactured by Dave Smith Instruments. It was first released as a desktop version in 2002, then later a 37-key keyboard bearing the same synth engine as the Evolver desktop was also released. A polyphonic version of the Evolver, dubbed the Poly Evolver, was released in 2004 as a rackmount version, then a 61-key keyboard version of the Poly Evolver was released in 2005. The Evolvers were replaced by new high end models, the Prophet 12 and the Pro 2.
The Oberheim Xpander is an analog synthesizer launched by Oberheim in 1984 and discontinued in 1988. It is essentially a keyboardless, six-voice version of the Matrix-12. Utilizing Oberheim's Matrix Modulation technology, the Xpander combined analog audio generation with the flexibility of digital controls logic.
The Korg PS-3300 is a polyphonic analog synthesizer, produced by Korg between 1977 and 1981.
The Steiner-Parker Synthacon is a monophonic analog synthesizer that was built between 1975 and 1979 by Steiner-Parker, a Salt Lake City-based synthesizer manufacturer. It was introduced as a competitor to other analog synthesizers, like the Minimoog and ARP Odyssey.
The AX60 is a polyphonic analogue keyboard synthesizer manufactured by Akai Professional in the mid-1980s. It was Akai's answer to the popular Roland Juno series synthesizers. The AX60 uses voltage-controlled analogue oscillators and filter circuitry based on the Curtis Electronics CEM 3394 integrated circuit.
Roland System-1 is a Plug-Out Synthesizer, based on the System 100, System 100M, and the System 700.
The Yamaha DX21 is a digital bi-timbral programmable algorithm synthesizer with a four operator synth voice generator which was released in 1985. It uses sine wave-based Frequency Modulation (FM) synthesis. It has two FM tone generators and a 32-voice Random Access Memory (RAM), 32 user voices and 128 Read Only Memory (ROM) factory preset sounds. As a programmable synth, it enables users to create their own unique synthesized tones and sound effects by using the algorithms and oscillators. The instrument weighs 8 kg (17.6 lbs). On its release, it sold for $795.