Eurorack is a modular synthesizer format originally specified in 1995 by Doepfer Musikelektronik. [1] [2] [3] [4] It has since grown in popularity, and as of 2022 has become a dominant hardware modular synthesizer format, with over 15,000 modules available from more than 1000 different manufacturers ranging from DIY kits and boutique, cottage-industry designers to well-known, established synth mass-manufacturers like Moog and Roland. [5] [6] [7]
Compact size, 3.5mm mono jacks and cables for patching all signals, and lack of a visual or sonic aesthetic defined by one manufacturer sets Eurorack apart from other modular synthesizer formats, and these factors have contributed to the popularity of Eurorack among both manufacturers and musicians. [8] [9]
Before Eurorack, in the late 1970s, several modular systems based on the industrial “Euro” card frames appeared:
By the late 1980s, these had all ceased production.
Dieter Döpfer built some Formant modules before producing his own systems. His Voice Modular System from the early 1980s was a Eurocard-based "modular" (the modules were non-patchable voice cards etc.) polyphonic synth, but the front panels look very similar to the later A100 modules.
In 1996, Doepfer Musikelektronik released the first Eurorack-format modular synthesizer system, the Doepfer A-100, followed by successive new series of compatible modules in 1997 and 1998. [3] In the UK, Analogue Systems had been independently developing a very similar format, with small technical differences such as the power connectors. Analogue Systems would later change their products to offer Eurorack compatibility. [10]
In the mid 2000s, other manufacturers such as Cwejman, Make Noise Music and TipTop Audio adopted Doepfer's Eurorack format and started designing and manufacturing compatible modules. [11] [12] [13]
By 2013, the Eurorack format had gained in popularity. Music technology journalists estimated that there were already at least 80 manufacturers offering over 700 modules, greatly expanding the musical possibilities available from a Eurorack system to include sampling and sample manipulation, West-coast-style wavefolding, DSP-based effects and more. [14]
In the mid 2010s, increasing interest in Eurorack modulars prompted large, well-known music technology manufacturers to start producing Eurorack-compatible equipment aimed at this new market. In addition to modules, manufacturers like Arturia started producing outboard devices such as the Beatstep and Microbrute [15] designed to be able to communicate with Eurorack modular synthesizers via 3.5 mm jacks transmitting control voltages. [16] In 2015 Moog released the Mother 32, a Eurorack-compatible semi-modular synthesizer. [17]
By the end of fall 2018, the ModularGrid website included more than 316 manufacturers. [18]
For synthesizers, Eurorack is a de facto standard to allow different modules to fit in the same cases and communicate among themselves. The basic requirement is compatibility with the Doepfer technical specifications:
The physical specification is based on the Eurocard standard of:
Eurorack modules may be further characterized by depth: shallow modules (2.5 cm to 4 cm ) can fit into "skiff" cases and are casually referred to as "skiff friendly".
The Eurorack electrical specification [22] defines a common bipolar 12 V DC power bus (+12V , 0 V, −12 V). This can be distributed by one of two connectors with a standard 2.54 mm (0.1 in) pitch:
Audio and control signals are exchanged between modules via 3.5 mm mono jack cables. The electrical characteristics of signals are split into three loosely defined categories:
Several manufacturers offer Eurorack-compatible modules in a smaller 1U tall format, sometimes referred to as "tiles". As of 2018, there are two competing standards for 1U modules, differing mainly in their height. 1U modules manufactured by Intellijel are 39.65 mm high, [23] whereas 1U modules manufactured by Pulp Logic and other manufacturers are 43.2 mm high. [24] Pulp Logic also proposes a more compact power connector for 1U modules, consisting of only three pins.
The most common source of sound in any modular synthesizer is a voltage-controlled oscillator. [25] They depend on a control voltage, a lot of times routed from external hardware (for example, an analog synthesizer with a CV output, or MIDI signals processed on a MIDI-to-CV converter), to both control pitch, and output different waveforms.
There are various control-voltage standards for determining the voltage/pitch relationship. The most popular ones are "volts-per-octave", where 1 V equals one octave, and "hertz-per-volt", where each octave equals doubling or halving the voltage. [26]
Under the category of source modules, [27] these modules are responsible for producing different “types” of noises (or colors). They can output (1) white noise — where all frequencies in the spectrum are equally powered, (2) pink noise — where there is more power to the lower end, due to its logarithmic nature, (3) brown noise — similar to pink noise, but steeper slope, (4) blue noise — oversimplified, the opposite of the pink noise, with more power concentrated on the higher frequencies, among others.
Under the category of processors, [28] modulators modify an incoming signal. [29] The effects produced are widely varied and a lot of times, modules are built for a specific function, for example:
Another kind of processor, [30] filters are modules shaping the sound by attenuating specific frequency ranges. These modules contain all or a selection of the following: (1) a high-pass filter (where anything above a certain frequency can “pass”), (2) a low-pass filter (anything below a given frequency can pass), (3) a band-pass filter (where anything “in between” two frequencies can pass), and (4) a notch filter (where one cuts a specific range of frequencies out allowing everything else to pass). [31]
Essentially, modules that can both operate as a source or a processor of musical content in the form of CV or MIDI messages. The most common kind are step-sequencers, where each individual musical event is triggered in a “step” of a bigger sequence (or loop).
Utility modules are the ones responsible for expanding certain capabilities of a specific setup. They can be used to combine, split, divide, multiply, quantize, or offset a signal. [32] One example of a utility module is a multiplier, that allow one to send any CV output to many other inputs. Another example are the attenuators responsible for scaling the CV signal with a control knob (much like faders in a mixing console).
A lot similar to the concept in a guitar pedal, effects modules are used to change the sound of an incoming signal. [33] They can be (1) dynamic processors, used to control the level of a signal (like compressors, or limiters), (2) equalizers, used to change the frequency characteristics of a given sound (sometimes in the form of a eurorack mixer module), or (3) special effects, like delays, reverbs, or choruses.
The technical and modular nature of Eurorack often attracts people who are interested in modifying or building their own modules or cases. Many Eurorack manufacturers started off as individuals building "do it yourself" (DIY) modules or offering DIY kits before expanding into production. Building DIY modules can be a gateway to learning more about electronics and physical manufacturing, as well as being satisfying and developing a more intimate connection with the synthesizer as a personal musical instrument.
Some manufacturers such as Befaco, Bastl Instruments and Erica Synths offer some or all of their modules both as assembled products or as kits to be assembled by the buyer. [34] [35] Doepfer offers a case and power supply kit, as well as 'low cost' cases designed to be customised and finished by the buyer.
Releasing modules exclusively as open source designs and DIY kits allows designers such as Music Thing Modular to design and release popular modules such as the Turing Machine or Radio Music without having to run a company or invest in manufacturing. Open Source licenses for both hardware and code allow individuals to build the modules from scratch, and companies such as Thonk to offer kits. [36] [37]
Some manufacturers do not offer kits or intend for end users to build their products, but release the code, schematics and layout under open source licenses. Émilie Gillet of Mutable Instruments cites transparency and the possibility for customers to customise or modify their modules as driving reasons for this decision. [38]
An analog synthesizer is a synthesizer that uses analog circuits and analog signals to generate sound electronically.
Modular synthesizers are synthesizers composed of separate modules for different functions. The modules can be connected together by the user to create a patch. The outputs from the modules may include audio signals, analog control voltages, or digital signals for logic or timing conditions. Typical modules are voltage-controlled oscillators, voltage-controlled filters, voltage-controlled amplifiers and envelope generators.
CV/gate is an analog method of controlling synthesizers, drum machines, and similar equipment with external sequencers. The control voltage typically controls pitch and the gate signal controls note on-off.
Doepfer Musikelektronik GmbH is a German manufacturer of audio hardware, mostly synthesizer modules, based in Gräfelfing, Upper Bavaria and founded by Dieter Döpfer. The product range covers analog modular systems, MIDI controllers, MIDI hardware sequencers, MIDI-to-CV/Gate/Sync Interfaces, MIDI master keyboards and special MIDI equipment.
The Moog synthesizer is a modular synthesizer invented by the American engineer Robert Moog in 1964. Moog's company, R. A. Moog Co., produced numerous models from 1965 to 1981, and again from 2014. It was the first commercial synthesizer and established the analog synthesizer concept.
Arturia is a French electronics company founded in 1999 and based in Grenoble, France. The company designs and manufactures audio interfaces and electronic musical instruments, including software synthesizers, drum machines, analog synthesizers, digital synthesizers, MIDI controllers, sequencers, and mobile apps.
The 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 that approximate those produced by conventional analogue synths by using DSP chips to digitally model analogue circuitry.
MOTM is the name of the modular synthesizer system manufactured by Synthesis Technology. MOTM is an acronym for "Module of the Month".
The Doepfer A-100 is an analog modular synthesizer system introduced by German audio manufacturer Doepfer in 1995. Although there were only 10 module types at time of release, it currently has more than 120 modules plus several different enclosures and accessories.
Korg MS-10 is an analogue synthesizer created by Korg in 1978. Unlike its bigger brother, the Korg MS-20, the MS-10 only has one VCO, one VCF and one envelope generator. It is monophonic and has 32 keys.
The Serge synthesizer is an analogue modular synthesizer system originally developed by Serge Tcherepnin, Rich Gold and Randy Cohen at CalArts in late 1972. The first 20 Serge systems were built in 1973 in Tcherepnin's home. Tcherepnin was a professor at CalArts at the time, and desired to create something like the exclusively expensive Buchla modular synthesizers "for the people that would be both inexpensive and powerful." After building prototypes, Tcherepnin went on to develop kits for students to affordably build their own modular synthesizer, production taking place unofficially on a second floor CalArts balcony. This led to Tcherepnin leaving CalArts in order to produce synths commercially, starting in 1974.
A synthesizer is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and frequency modulation synthesis. These sounds may be altered by components such as filters, which cut or boost frequencies; envelopes, which control articulation, or how notes begin and end; and low-frequency oscillators, which modulate parameters such as pitch, volume, or filter characteristics affecting timbre. Synthesizers are typically played with keyboards or controlled by sequencers, software or other instruments and may be synchronized to other equipment via MIDI.
The Roland System-100M was a modular analog synthesizer manufactured by the Roland Corporation in the late 1970s and early 1980s. It was the successor of the Roland System-100, a semi-modular keyboard.
The RS Integrator is a series of analog modular synthesizer systems made by British company Analogue Systems, which had previously manufactured the TH48 step sequencer and FB3 Filterbank.
The Grandmother is an analog semi-modular subtractive, 32-key synthesizer released by Moog Music Inc., incorporating circuits based on the Moog modular synthesizer Model 15 and the Minimoog.
The Mother-32 is a semi-modular analog synthesizer. Introduced in 2015, it was the first tabletop unit produced by Moog Music. It has a single voltage controlled audio oscillator, a voltage controlled low frequency oscillator, a voltage controlled filter switchable between high and low pass, an AR envelope generator with switchable sustain, a voltage controlled amplifier, and a white noise generator. It also features a 32–step monophonic sequencer, a 13-note keypad, and a 32-point patch bay including assignable outputs. The Mother-32 is manufactured in Asheville, North Carolina.
The Mother-32 is an analog semi-modular desktop synthesizer released by Moog Music Inc. in 2015.
The Ming Mecca is a pixel art-oriented modular sound and interactive video synthesizer designed by Jordan Bartee, manufactured by Special Stage Systems, and released in 2014. It was followed by the Ming Micro in 2016.
The Volca Modular is an analogue synthesizer manufactured by the Japanese music technology company Korg. It is part of their popular Volca series of affordable electronic synthesizers and drum machines. Like other Volcas, it sports a 16-step sequencer and can be powered by batteries.
The Neutron is a dual-oscillator monophonic synthesizer manufactured by Behringer. Released in 2018, the Neutron has an analogue signal path and uses subtractive synthesis to produce sounds. It is semi-modular and compatible with Eurorack voltages.