AIRA Modular: What is a Modular Synthesizer?

The world of modular synthesizers can be confusing and intimidating. Let’s find out what lies behind the wall of cables and why modular is back!
Contributed by Christian Moraga for the Roland Australia Blog If you are a fan of music production or electronic music, you might have recently noticed a new instrument gracing the stages and studios of your favourite producers and musicians. This instrument (that looks more like a computer network device than instrument) features a series of knobs and jacks, buttons and switches, blinking lights and screens all hidden behind a wall of patch cables. This instrument is in fact not new, but one that is experiencing a resurgence in popularity – this is a modular synthesizer. But what are all of those cables for? …and where is the keyboard??
A keyboard synthesizer has a fixed signal path with limited modulation options.
The structure of the modular synthesizer is different to the now traditional keyboard synthesizer. A keyboard synthesizer comprises of oscillators, filters, envelopes and an amplifier that are all hard-wired together in a signal chain. When playing the keyboard synth, you shape the sound by altering the knobs and switches but the signal chain always remains fixed in the one path. A modular synthesizer does not require a keyboard to be played. The basic modular synthesizer is comprised of the same blocks as a traditional keyboard synthesizer but each function is self-contained in its own “module” (hence, modular synthesizer). No module is hard-wired – each one has an input and output and the signal chain can take an infinite amount of paths. The connection of module-to-module via cables is referred to as a “patch” and the bigger the modular system, the more combinations of sounds are available to you.
A modular synthesizer allows for a flexible signal path with a wide choice of modulation options.
A modular synthesizer allows for a flexible signal path with a wide choice of modulation options.
The modules available in a modular synthesizer can be divided into three types; SOURCE, PROCESSOR, and LOGIC.

• SOURCE modules typically have a signal output and no signal input. These are sound sources like oscillators (VCOs) and noise sources, and also control sources like LFOs and Envelope Generators.

• PROCESSOR modules shape the sound via timbre (VCF), volume (VCA) or effects (Delay, Phaser, Ring Modulator)

• LOGIC modules provide information to control clock timings and can also be used for switching (e.g. NAND gates, clock pulse triggers).

This infinite world of sound exploration via the modular synthesizer favours the more adventurous musician. A new level of control over your sound is now available to you and is an advantage that the modular synthesizer has over traditional keyboard synths… if that is the “synthesis” path you wish to travel.


On a keyboard synthesizer, to play a note you press down a key. Simple. But how do you play notes on a modular synthesizer, especially if there is no keyboard? The answer is CONTROL VOLTAGE. Let’s go back to the keyboard… When you press down a key on the keyboard synthesizer, an electronic signal is sent to the oscillator that is measured in volts. This signal controls the pitch of the oscillator, with the number of volts corresponding to the octave of the key played on the keyboard. 1vperoctaveFor example, the higher the key played on the keyboard, the higher the voltage. This means, a 3V signal is one octave higher than a 2V signal, as in the image above. A signal used to control another parameter is referred to as Control Voltage or CV. In the example above 1 Volt per Octave control voltage (1V/Oct CV) is a synthesizer standard when controlling pitch in a synthesizer. Control Voltage is also used in modular synthesizers and is the way in which each module interconnects and “speaks” to each other. Each module not only has an input and an output, but also has CV inputs to control individual parameters of a module. One control voltage source can control any number of inputs like pitch, volume or cutoff, individually or all parameters simultaneously. The video below is an example of how to use an eight-step control voltage sequence in multiple ways: Control Voltage has the ability to be multiplied, combined, switched and mixed to create a random and evolving swirl of complex signals to control your modular synthesizer. This is the moment when the “beast has a mind of its own”. This serves as a source of inspiration to you as a musician to create sounds, melodies and textures you could never have imagined. On the other hand, since the modular synthesizer uses precise voltages to control parameters such as pitch and tempo, the “beast can also be tamed”. The classic Moog Modular Synthesizer was traditionally played with a keyboard to recreate more traditional instruments like flutes and horns – the modular then becomes an almost symphonic instrument. These two opposing schools of synthesis was how the world of synthesis was born with the first modular synthesis albums the very proof of that. The first modular synthesizers built in 1963, the Moog Modular Synthesizer in New York and the Buchla Modular Synthesizer in California, inspired the east-coast and west-coast schools of synthesis and shaped electronic music to come.


ROLAND SYSTEM-700 roland aira modular synthesizer system-700 In 1976, the Roland Corporation built the first — and only — modular synthesizer to be made in Japan – the Roland SYSTEM-700. This beast of a synthesizer featured six cabinets, a wall of modules and a five-octave keyboard –all for a measly ¥2,650,000 in Japan (roughly $12,000). The SYSTEM-700, designed for the professional studio, featured one main console (or block) that allowed for expansion with smaller blocks. Expanding a system allows for more synth “voices” to be added to the mix and for more complex sounds when using multiple control voltages. The main console consisted of:
  • 3 Voltage Controlled Oscillators (with four waveform outputs)
  • 2 Voltage Controlled Filters (one 24dB Low-Pass and one Multi-mode)
  • 2 Voltage Controlled Amplifiers (with Linear/Exponential CV)
  • Noise Generator (White and Pink)
  • 2 Dual ADSR Envelopes
  • 2 Low Frequency Oscillators (with four waveform output and PWM).
  • Ring Modulator (with selectable VCO output for {x} and {y})
  • Sample & Hold (with Clock and Sample I/O)
  • Spring Reverberator (with 3-channel input mixer)
  • Phase Shifter (with two VCA hard-wired inputs)
  • 3×2 Audio Mixers with Panning Sliders
  • 2 Multiple Jack Panels
  • Voltage Amplifier, Envelope Follower, Integrator (Lag Processor) Module
  • Voltage Processor/Inverter
  • Tuning/Test Reference Oscillator
  • Monitor Section (headphones)
Amongst the additional expansion blocks featured a Keyboard Block and a 3 x 12-step sequencer – the 717A block. This sequencer block has many features that are still unique to this day. Each of the three channels of 12-steps have a musical value selector (1 whole note to 1/32 note) and multiplier that can allow for complex polyrhythms across all three channels. Each step also has an ANALOG IN that allows for a CV or audio signal to be switched in to the sequence. ROLAND SYSTEM-100M roland aira modular synthesizer system-100mIn 1978, Roland introduced the Roland SYSTEM-100M modular synth to the masses. This compact modular synthesizer was made up of various modules and a rack with built-in power supply (a 32-key and 49-key keyboard was available). The SYSTEM-100M blocks racks connect via an 8-pin DIN cable that also made a series of CV/Gate and trigger connections. Technically, this makes the SYSTEM-100M semi-modular with this format eliminating many external patch cables – an ideal situation for the synth enthusiast. One of the most coveted SYSTEM-100M modules is the M-172 Phase Shifter, Audio Delay, LFO, Gate Delay. This featured packed analog module contains a five-step phase shifter, a very short BBD delay (perfect for doubling and flanger-like effects), a gate delay and a triangle-wave LFO. The LFO is normalled (internally connected without a jack inserted) to the Phase Shifter and Audio Delay sections to create synchronised stereo, spatial and ensemble effects. roland aira modular synthesizer system-100m Award-winning composer, Hans Zimmer, is the owner of perhaps the most famous Roland SYSTEM-100M modular synthesizer. Zimmer purchased a bulk of 100M modules and has a 58 (!) VCO system at his disposal, which you have probably heard on a few of his film scores.


Roland recently announced a return to the modular format with the SYSTEM-1m Semi-Modular Synthesizer, four tabletop/Eurorack effects and five new analog SYSTEM-500 Modules. These new modules integrate analog, digital, plug-out and app technology to forge a new era of modular synthesizer. roland aira modular synthesizer eurorack SYSTEM-1m The SYSTEM-1m is a semi-modular synthesizer with PLUG-OUT capability and a unique design that can be used as a Eurorack module, tabletop synth, or 19” rackmount unit. In addition to being a powerful standalone instrument, the SYSTEM-1m has external inputs and an array of CV/Gate connections that allow it to be re-patched and to interface with other modular synthesizer systems. roland aira modular synthesizer system-1m MODULAR EFFECTS BITRAZER BITRAZER is an intense bit and sample rate crusher effect that can add edgy character or create total sonic mayhem. DEMORA DEMORA is an all new delay algorithm with a smooth, creamy sound and quick response that is as fun to tweak as it is to hear. With the massive range of delay times and buffer hold function you can create anything from ultra-subtle widening to dramatic rhythmic effects. SCOOPER SCOOPER is an ultra-modern effect that can sample, mangle, degrade and glitch captured loops of incoming audio. After capturing an audio loop, you can use SCOOPER to djust the loop’s pitch as well as process it through a filter section and various Scatter types that slice and warp individual steps. TORCIDO TORCIDO can produce tones ranging from gentle, warm overdrive to heavy distortion. Both the distortion amount and tone parameters have input level controls for adjusting the modulation range when controlled from an external source. roland aira modular synthesizer bitrazer torcido scooper demora Each of the four AIRA Modular effects also have a sub-modular system under the hood! You can fully customize the internal signal path by re-patching its array of virtual sub-modules via a custom application that works on Mac and PC as well as iOS and Android devices. Submodules are “re-patched” through a simple and intuitive drag-and -rop interface that even lets you choose which parameters are assigned to the high-resolution “GRF” knobs. Save, share and recall patches in real-time. AIRA Modular have brought preset technology to Eurorack and well into the future! The 15 virtual sub-modules are (with more available through future expansion): LFO, ADSR, NOISE, SAMPLE & HOLD, RING MOD, FILTER 6dB, FILTER 12dB, TONE, AMP, MIXER, STEREO MIXER, CURVE CONV, GATE DIVIDER, TRIG TO CV DELAY TIME, MIDI CLOCK TO GATE SYSTEM-500 Roland SYSTEM-500, an all-new, fully analog modular synthesizer is based on two of the most revered electronic instruments of all time—the SYSTEM-700 and SYSTEM-100m. Designed exclusively for Eurorack, the SYSTEM-500 delivers classic Roland sound with all the advantages and reliability of a modern instrument.


system1m_sml roland aira modular synthesizer bitrazer crusher roland aira modular synthesizer torcido distortion roland aira modular synthesizer demora delay roland aira modular synthesizer demora delay

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Created by Roland V-Drums specialist Simon Ayton, these patches were designed using the internal factory sounds and many of the techniques covered in the TD-50 guide. Enjoy exploring the possibilities!