How to connect the synth module to keyboard

Ever since its invention in the 60s, synth modules are making a resurgence in mainstream music production over the recent years. But, how do you connect a synth module to a keyboard?

If you are fond of creating music or you enjoy listening to electronic music, you have likely come across a small-ish box with loads of knobs, jacks, and switches and buttons. That instrument is a synth module, also known as a modular synthesizer. Basically, a synth module produces different sounds with the help of its various modules, including oscillators, amplitude control, filters, and many more. However, you also must have noticed that it does not come connected to a keyboard. So, let us figure out how to connect a synth module to a keyboard.

Synth modules

A synth module is an electronic musical instrument that contains a multitude of components (modules) that work together to create electronic music. It consists of the same blocks as the traditional keyboard synthesizer. However, each function operates on its own as it is contained in its own module. With the help of patch cables, sliders, patch panels, and switches, these modules connect in an infinite amount of ways, exposing the more adventurous musician to an endless world of sound exploration.

There are two types of modular synthesizers; digital and analog, which can be classified further into individual, desktop, and semi-modular. Modular synths require a sound source that can be manipulated and tweaked in various ways to create a variety of sounds. The audio source could be a sequencer, a keyboard, or a simple frequency signal. Now, let us discover how you can connect your synth module to your keyboard controller.

Connecting a synth module to a keyboard

Traditionally, synthesizers came with a fully-sized keyboard within the unit. These keyboard synthesizers came with filters, oscillators, amplifiers, and envelopes, all of which were hard-wired together in a single chain. By altering its switches and knobs, you could shape the sound produced, but its signal chain remains precisely the same.

Due to technological advancements, you do not need a keyboard to use a synth module. Modular synthesizers have the same blocks as the keyboard synthesizer. However, the difference comes in whereby each function is self-contained in its own module. In turn, each module has its own input and output, and its signal chain can connect in an infinite amount of ways. Each module connects to another module via patch panels, and the bigger the modular synthesizer, the more sound combinations it can make.

You can connect your synth module to your keyboard by using MIDI. But what is MIDI?


MIDI is how devices send information to each other, allowing you to control different parameters within such devices. It is a unique language that contains no audio content, but sends out digital signals to your sound source, instructing it on how to perform. Its controller features several commands, like ‘Note on,’ which refers to the pitch of each note, ‘Note off,’ which indicates when a note has been released and when it should end, ‘Velocity information,’ and many other advanced controls.

Connecting your keyboard to your synth module via MIDI allows you to play it like the traditional keyboard synthesizer. You will notice that your keyboard has a MIDI output, which will seamlessly connect to the MIDI input of your synth module via a MIDI cable. The type of MIDI-to-CV converter used dictates the amount of MIDI your synth module receives.

You might also find that your keyboard has a dedicated in-built CV and Gate outputs, which can also be used to send information to your modular synthesizer without the need for the MIDI-to-CV converter.

Control Voltage

It is crucial for anyone who wants to master a synth module to understand how to speak ‘control voltage’ (CV). By fully understand CV, you will have the know-how on how to connect your synth module to various other controllers, as well as create patches by connecting individual modules to your modular synthesizer.

Control voltage refers to electrical signals used by one module to control another. When you connect multiple CV sources, such as on/off signal, tempo, and pitch, to various destinations using patch cables, you create a patch.

Generally, the control voltage is crucial in three functions, which are gate, modulation, and triggering. Modulation, or to modulate, refers to shaping a sound source. ADSRs and LFOs are popular tools used to develop the volume of a synth patch, sweep a filter or alter the pulse-width for timbral effects.

CV Gate refers to when a note is pressed and the duration in which it should be pressed. Gate signals are also designed to turn various parameters on and off. More so, when gate signals are sent to an ADSR, the CV determines the shape of that envelope.

When it comes to triggering, a trigger signal refers to a short burst of voltage. Triggers control drum sequences and the tempo of a patch. The trigger will initiate sound from the sound module, making it an essential tool when clocking your synth module from external devices.

Sometimes, you may find that your keyboard, sequencer, or MIDI controller and synth module only takes CV. As a result, understanding how CV works will help you make this connection, increasing the possibilities of creating versatile sounds.

MIDI-to-CV converter

A MIDI-to-CV converter speaks both MIDI and CV languages. It converts MIDI signals into Control Voltage, allowing you to connect your MIDI external hardware to your synth module. As a result, you can share information gate and pitch information, or even have more advanced controls like velocity, pitch, aftertouch, and mod wheel operations, between your synth module and other external machines, such as the keyboard.


Understanding how a synth module works enable you to know how to alter and manipulate it to work best for you. Now, you can confidently connect your keyboard to your synth module with ease via MIDI. More so, keep an eye out for some modern analog synthesizers that feature USB connectivity, meaning there is an even more universal method of communicating MIDI information. Such connectivity allows you to share information via a broader range of devices as compared to MIDI or CV.

Peter Smith

Welcome to MusicGearAdvisor! 4 years ago I rediscovered my passion for making music and began building my own home studio. As I have gone through my journey I realized that I am just as passionate about the equipment as I am about the music. I started MusicGearAdvisor as a way for me to share my learnings with others so you can get started making music that you dream of.

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