Synthesizers are an invention of the 20th century that completely revolutionized music. They are the reason that the electronic genre was born.
Synthesizers use either digital or analog processing to reproduce the sound of acoustic instruments. There are many different types of synthesizers, which can be categorized into digital vs. analog, monophonic vs. polyphonic, etc.
To understand what a semi-modular synthesizer is, let’s categorize synthesizers in terms of modular vs. non-modular.
A modular synthesizer is a synthesizer entirely composed of modules. Modules are the separate components of a synthesizer, which are connected via patch cables to create different sounds.
Modular synthesizers do not have a predetermined signal path, unlike non-modular synthesizers. There are minimal inputs on non-modular synthesizers, which makes them easier to use. This also means you have less creative freedom.
A semi-modular synthesizer combines the best of both worlds. The synthesizer comes with a predetermined signal path, but you can change it. It is often considered the most flexible option.
Modular Vs. Semi-Modular
As you can tell, modular and semi-modular synthesizers are not that far from each other. The real question is which one to purchase. What are the pros and cons of each synthesizer?
Pros and Cons of Modular Synthesizers:
The biggest advantage of modular synthesizers is how incredibly customizable they are. You have complete creative freedom to create all sorts of unique sounds.
There are two main types of modular synthesizers: Eurorack and Moog. Eurorack modular synthesizers are the most popular. This type of modular system contains modules that share the exact height and varying widths.
Eurorack modular systems often contain a combination of digital and analog sound processing, which is another advantage of modular synthesizers.
On the downside, modular synthesizers can be challenging to work with. They are also more expensive than other synthesizers and make it difficult to manage polyphony.
Pros and Cons of Semi-Modular Synthesizers:
Semi-modular synthesizers allow freedom of choice. The system has a default signal path, which you can decide to implement or alter.
Semi-modular synthesizers offer you the convenience of a non-modular system combined with the flexibility of a modular system.
Semi-modular synthesizers are often less expensive than modular synthesizers. They are also a great way for people to become familiar with modular systems.
If you want to work with modular synthesizers, it’s advisable to start with a semi-modular system.
Semi-modular synthesizers are not as limitless as modular synthesizers because of their internal wiring. They are often monophonic rather than polyphonic.
The 15 Best Semi-Modular Synths
1. Moog Grandmother
- 41 patch points
- 2 oscillators
- 4-pole ladder filter
- Built-in spring reverb
- Built-in arpeggiator and sequencer
The Moog Grandmother is described as a “sonic playground,” which is a perfect description. The Grandmother is a relatively small synthesizer that weighs around 15 pounds.
Even though the Grandmother might look simple, there is plenty of potential. The Grandmother contains a real spring chamber inside it. The built-in spring reverb delivers impressive vibrant sound.
Both oscillators can produce four waveforms: triangle, sawtooth, square, and pulse.
The Grandmother’s built-in sequencer allows you to store up to three sequences in memory. This is ideal if you want to create rhythms and soundscapes.
The arpeggiator lets you create rhythmic patterns by holding notes on the keyboard. It also gives you access to the playback direction and octave range.
The Grandmother is one of the best, if not the best semi-modular synthesizer for beginners. It requires no patching to begin working but offers many features to experiment with.
One of the biggest drawbacks of the Grandmother is that it’s a monophonic synthesizer.
However, Moog released a polyphonic version of the Grandmother called the Matriarch. The Moog Matriarch is an excellent option for those who want something a little bigger and with more features.
2. Behringer Neutron
- Monophonic & paraphonic
- 2 oscillators
- 56 patch points
- Sample-and-hold circuit
- Bucket Brigade Delay (BBD)
- Filter Mode
The Behringer Neutron is inspired by the portable analog synthesizers of the 70s and 80s. The Neutron stays true to this era in both its design and sound.
The Neutron’s semi-modular and portable design makes it easy to use. All you have to do is connect the Neutron to a keyboard or computer and you can start experimenting.
The Neutron’s signal paths are VCO, VCF, and VCA. All of which were used to create the chill electronic tracks from the 70s and 80s.
The Neutron features a range of five waveforms: tone mod, square, sawtooth, triangle, and sine. The waveforms can be adjusted across a 3-octave range.
The Filter Mode adjusts the tone in three settings: high-pass, band-pass, and low-pass. The BBD circuit provides 25-640 ms of delay time. The higher you adjust the delay time, the stronger your echoes will be.
The Behringer Neutron is one of the most affordable and high-quality analog synthesizers. You can buy it for as low as $300.
3. Korg MS-20 Mini
- 37 mini keys
- External Signal Processor (ESP)
- 2 oscillators
- First-generation filter design
The Korg MS-20 Mini is based on the Korg MS-20 from 1978. The Mini includes most of the features of the MS-20; the only difference is that the Mini is much smaller.
The Mini contains two oscillators and envelope generators with the hold-and-delay feature. The Mini utilizes the iconic filter of the MS-20. The filter provides excellent resonance on both the high-end and low-end. It also provides a dynamic sound and range.
The ESP allows you to change the pitch or volume of an outside audio source. The Mini’s patching system is extensive and flexible.
There are many unique sounds you can create from the various units. The Mini is compatible with MIDI IN and USB.
4. Pittsburgh Modular Microvolt 3900
- Advanced VCA system
- Includes a 39-point Eurorack format patchbay
- Four-stage envelope generator
- Binary Filter
- 2 oscillators
- Built-in arpeggiator
- 16-step sequencer
The Microvolt 3900 features advanced VCA technology. Most VCA systems work in two dimensions, but the Microvolt 3900 adds a third dimension. This addition mimics the way sound behaves in nature.
The Microvolt 3900 does not require patch cables, but it includes a 39-point Eurorack patchbay for further exploration.
The dual oscillators generate saw, sine, pulse, and folded waves. The four-stage envelope generator features four adjustable stages: attack, decay, sustain, and release.
The binary filter provides the Microvolt 3900 with an impressive range- it can shift from a clean sound to a frenetic sound.
5. Make Noise 0-Coast
- 2 oscillators
- MIDI capability
- Patchable (13 sources & 14 destinations)
- Desktop analog design
- Timbre controls
The Make Noise 0-Coast is inspired by Moog and Buchla-style synthesizers. The 0-Coast’s sound source components are Buchla-inspired, while its circuits are Moog-inspired.
The 0-Coast is relatively small but features many components. It has a Control, Oscillator, Overtone, Multiply, Slope, Contour, and Dynamics section.
The Control section features the MIDI, clock, random voltage, and CV processing circuits. The Oscillator section is voltage-controlled, and it generates triangle and square waveforms.
The oscillators are connected to the Overtone section, which lets you add harmonics to the triangle and square waveforms. This creates a unique and dramatic effect on the sound.
The 0-Coast’s Contour and Dynamics section gives you control over the amplitude and frequency. The 0-Coast works with and without patch cables.
6. SoftPop 2
- Analog with digital sequencing
- Multimode filter
- 37-point Eurorack patchbay
- 8-step sequencer
- MIDI input
- Triangle-core oscillators
The SoftPop 2 is a dynamic bomb of sound. The SoftPop 2 is different from most semi-modular synthesizers. For starters, it is simultaneously an analog and digital synthesizer.
SoftPop’s sequencer is built upon 8-step loops of notes, gates, and slides, which can be rearranged to create longer sequences. You can also add modulation to the pitch using the Pitch Mod feature.
SoftPop’s multimode filter provides a wide range of unique sounds- it is the perfect synthesizer for playful experimentation. It also includes a built-in tuning feature that automatically tunes your melodies.
The SoftPop 2 features many connectivity options, and it is compatible with many devices. Overall, the SoftPop 2 is a unique and fun synthesizer with much potential and flexibility.
7. Moog Mother-32
- 32-point patchbay
- 13-button, 1-octave keyboard
- MIDI input
- Noise generator
- Attack and Delay controls
The Moog Mother-32 is a Eurorack synthesizer with a 32-point patchbay and a 13-button, 1-octave keyboard.
The Mother-32’s oscillator produces saw and pulse waveforms. You can modify the width of the pulse wavelength. The oscillator creates a classic analog sound.
Since the Mother-32 is a subtractive synthesizer, the filter is crucial to the sound. Subtractive synthesizers work by eliminating unwanted frequencies through a filter. This, in turn, produces the desired sound effect.
The Mother-32’s filter creates warm low-range sounds and sharp high-end sounds. The noise generator helps create percussive sounds. In addition, Mother-32’s Attack and Delay controls let you structure your sound.
8. Analogue Solutions Fusebox
- 3 VCOs
- Pitch & pulse width adjustability
- White noise
- Multimode Filter
- 2 envelope generators
- Interval generator
The Analogue Solutions Fusebox synthesizer revives the vintage synth sounds. The synthesizer features three voltage-controlled oscillators (VCO).
The first voltage-controlled oscillator features an octave and a cross-modulation switch. Both the second and third VCOs have a wide range switch. The third VCO also features a MIDI pitch control that can be disabled anytime.
All VCOs produce sawtooth and square waves. You also have the ability to adjust pitch and pulse width.
The multimode filter features low-pass, high-pass, band-pass, and notch filters. Notch filters are pretty rare in most synthesizers- they are often used to reduce noise.
Fusebox’s interval generator lets you set six different pitches to each of the switches and then interchange the VCOs. The Patternator is a combination between a step-sequencer and an arpeggiator.
9. Arturia Minibrute 2s
- 2 oscillators
- 2 envelopes
- Built-in sequencer and arpeggiator
- 48 CV patch points
- 64-step sequencer
- Fits in RackBrute case
The Arturia Minibrute 2s progresses the design of the Minibrute 2. The Minibrute 2s features two Brute oscillators and the Steiner-Parker filter.
The oscillators feature waveform mixing, wave shaping, and frequency modulation. The Steiner-Parker filter is smooth at low-range but becomes aggressive when you overdrive it.
Minibrute 2s’s arpeggiator features multiple modes, so you can experiment with everything from fluid chord progressions to tap tempo. You can record up to 64 steps of melody with the sequencer.
The 48 CV patch points make the Minibrute 2s a perfect companion for a Eurorack synth rig. Luckily, the Minibrute 2s is designed for the RackBrute case, where you can contain all your synth equipment in one place.
10. Korg Volca Modular
- 8 modules
- 50 patch points
- 16-step sequencer
- 14 scales
- Micro tuning
- Sync jack
- 2 triangle oscillators
The Korg Volca Modular is a compact size synthesizer inspired by “West Coast style” synthesis. It consists of eight modules, 50 patch points, and two triangle VCO carriers.
The 16-step sequencer gives you a lot to work with. You can connect up to 16 sequences with over 256 steps to create large-scale productions.
The micro tuning feature lets you adjust the pitch of each note. You can also choose from 14 types of scales.
The Volca Modular consists of two envelope generators and an AHR generator that allows for the attack, hold, and release functions. There is also a Rise-Fall generator that applies a time-varying change to the sound.
The Korg Volca Modular is easily connectable to other synth equipment through the synth jack. The synth jack lets you connect to any Korg groove machine.
11. Moog Mavis
- 24-point patchbay
- Full range analog oscillator
- Voltage-controlled filter
- 4-stage envelope generator
- Wavefolding circuit
- Hold (S+H) circuit
- Protective cover
The Moog Mavis is a budget-friendly analog synthesizer with a 24-point patchbay. The oscillator features pulse width modulation, waveform mixing, and mod source mixing.
The Mavis features a -24dB ladder filter and a 4-stage envelope generator. The wavefolding circuit makes it possible for additive synthesis to collaborate with subtractive synthesis.
The (S+H) circuit produces a random CV pattern that can modulate other parameters. The Mavis comes with a fitted cover that protects the instrument when you take it on the go.
12. Dreadbox NYX V2
- 30 patch points
- 2 oscillators
- Dual filter’
- Drone mode
The Dreadbox NYX V2 is a paraphonic analog synthesizer with 30 patch points. The oscillators generate saw, square, and triangle waveforms.
The dual filter ranges from a 12dB/octave lowpass to a 24dB/octave bandpass. The drone mode is ideal for creating ambient soundscapes.
The synthesizer also features a white noise generator, three loopable envelope generators, and an auto-tuning function.
13. Arturia Buchla Easel V
- 5-step sequencer
- Envelope generator
- 10 effects
- 4 voices of polyphony
The Buchla Easel V is the first recreation of the iconic 1973 Buchla Music Easel. The Easel V features a keyboard like the original model.
The Easel V includes a five-step sequencer and click-and-drag patchbay. The modulation oscillator can be used as an LFO (low-frequency oscillator), or you can dial it up.
Arturia designed extra features on the Easel V like polyphony, control sources, and onboard effects. The Easel V has 10 effects, including phaser, flanger, chorus, overdrive, and delay.
14. Dreadbox Erebus V3
- Analog & duophonic
- 3 oscillators
- Auto tuning
- Triple ring modulator
- Lo-Fi echo
- White noise generator
- 3 LFOs
The Dreadbox Erebus V3 is a duophonic synthesizer with 35 patch points. Duophonic synthesizers can only play two notes at a time.
All three oscillators feature auto-tuning ability. The waveforms they generate are saw, reverse saw, pulse, sine, and white noise. The triple ring modulator is capable of producing powerful timbres.
The Erebus V3 includes a 12dB multimode filter as well as a built-in Lo-Fi echo effect. It also features an analog clock generator, a white noise generator, and three low-frequency generators.
15. Cre8audio East Beast
- PGH filter
- Envelope generator
- 18 patch points
- Built-in tempo clock, arpeggiator & sequencer
Cre8audio’s East Beast is a subtractive, monophonic synthesizer. The East Beast is fully patchable with a total of 18 patch points.
It features a 32-step sequencer with up to 13 presets. The oscillator produces sine, triangle, saw, square, and pitched noise waveforms. The oscillator also features pulse width modulation and frequency modulation.
East Beast also includes a built-in tempo clock, arpeggiator, and sequencer. One of the best filters is its PGH filter, which has no dead spots.
The PGH filter is a multimode filter- it can be used as a low-pass filter, high-pass filter, band-pass filter, or a combination of all three.
Buying Guide: How to Choose the Right Semi-Modular Synth For You
As you can tell, most synthesizers are composed of the same components and features. However, this does not mean that all synthesizers sound the same- far from it.
Each component or feature in a synthesizer is designed differently. What might result in synthesizers sounding the same are presets.
The synthesizer that is right for you will depend on your level of experience, budget, and sonic preference. However, there are some common features to consider regardless of your personal circumstances and taste.
Below is a brief rundown of some features to look for in semi-modular synthesizers:
Monophonic, Polyphonic, & Everything in Between
As discussed previously, monophonic synthesizers can only play one note at a time. Polyphonic synthesizers, on the other hand, can play any number of notes.
In between monophonic and polyphonic synthesizers, we have duophonic and paraphonic synths. Duophonic synths can only play two notes at a time.
The term paraphonic has nothing to do with the number of notes you can play. It simply means that every note goes through a single filter and voltage-controlled amplifier.
So, which one should you get? Monophonic synths are ideal for people who want to play very specific and complex sounds. Polyphonic or duophonic synths are for people interested in the textures and broad ranges of sound.
Voices are what dictate how many notes a polyphonic synth can play. The more voices a synthesizer has, the more complex chords it can generate.
If you are purchasing a poly synth, make sure to consider how many notes you would want to play at once.
Arpeggiators allow you to play any chord in a looping pattern. Most arpeggiators can produce four patterns: ascending, descending, ascending and descending, and random.
However, some arpeggiators feature additional pattern sequences and may allow you to create your own.
Look closely at the arpeggiator of the synth you are interested in buying. There might be advanced arpeggiator features you might want.
Sequencers allow you to playback a series of notes automatically. Unlike an arpeggiator, a sequencer allows you to pick which notes you want to play and in which order.
The more steps a sequencer can manage, the more memory it has. Most sequencers go up to 64 steps, but some can go lower or higher.
Oscillators are what generate the sound on a synthesizer. Synths that have two or more oscillators let you create a complex tone.
Oscillators produce four main waveforms: sine, triangle, pulse (square), and sawtooth. LFOs also generate waveforms but at a low frequency. Not all LFOs have all the waveforms available- it depends on the synth you are buying.
Filters cut out certain frequencies, which changes the tone and sound. Filters vary greatly from synthesizer to synthesizer.
The most common filters are low-pass, high-pass, and band-pass filters. Many synths feature multimode filters, which means they feature all the filters above.
Some synths include more advanced filters like ladder filters, Steiner-Parker filters, and SEM filters. These filters produce drastically different sounds, so it’s important to consider your sonic preference.
Envelope generators modulate amplitude over a period of time. The most prevalent type of envelope generator is an ADSR envelope.
The four stages of an ADSR envelope are attack, decay, sustain, and release. However, some synths feature rarer types of envelope generators. Some of these generators are AHDSR and DADSR.
Frequently Asked Questions
A plugin is an online synthesizer that you can use with other music software. There are many fantastic modular synth plugins you can download.
We strongly recommend checking out the Hyperion plugin. The Hyperion includes various features like multiple synthesis types, flexible patching, and tuning.
The iconic musician Aphex Twin has worked with many synths throughout his career, including the Roland SH-101.
Aphex Twin has also utilized modular synths like Make Noise Erbe-Verb, M.A.S.F. Mo.S, and the Epoch Modular Benjolin.
PSU stands for power supply unit. The purpose of a PSU is to supply power to your modules. Semi-modular PSUs often have many more cables than modular PSUs.
One of the best modular synth systems is the Behringer System 55. This modular synthesizer is jam-packed with features. It features 38 vintage-sounding synth modules.
There are many incredible semi-modular synths for ambient music. We especially recommend the Make Noise Strega, the 0-Coast, and the Moog Mother-32.
Semi-modular synthesizers are a dynamic and versatile type of synths. They are a great stepping stone towards modular synths. They are also a more affordable option for those who want to heavily experiment.
Luckily, there are many different semi-modular synthesizers to choose from. Remember to consider all the factors mentioned earlier before purchasing a synth.