How Does A Music Synthesizer Work?

Interested in the world of music synthesizers and ever wondered, “How Does A Music Synthesizer Work?” This article is dedicated to uncovering the inner workings of these fascinating devices.

Whether you’re a musician, a tech enthusiast, or simply curious, understanding the process will enhance your appreciation of the art form. We will delve into sound waves, their generation, manipulation, and the essential components that bring a music synthesizer to life. Join us on this sonic journey as we answer the question, “How Does A Music Synthesizer Work?” and reveal the magic behind your favorite songs.

Triggering Sound Generation

Control Voltage

In a music synthesizer, sound generation is triggered by control voltage (CV). Control voltage is an electrical signal that determines various parameters of the sound, such as pitch, modulation, and filter cutoff. It is typically generated by a sequencer, keyboard, or other external devices, and sent to the synthesizer to initiate sound generation.

Control voltage signals can be in the form of analog voltages or digital signals, depending on the type of synthesizer. Analog control voltage allows for smooth and continuous changes in the sound parameters, while digital control signals offer more precise and accurate control.

MIDI Signals

Another common method of triggering sound generation in a synthesizer is through MIDI signals. MIDI (Musical Instrument Digital Interface) is a protocol that allows electronic instruments and computers to communicate and synchronize with each other.

MIDI signals typically contain information about which notes to play, the velocity of the notes, and various other control messages such as pitch bend, modulation, and sustain. These messages are sent from a MIDI controller, such as a keyboard or computer, to the synthesizer, which interprets the messages and generates the corresponding sound.

MIDI signals offer a flexible and widely compatible way of triggering sound generation in synthesizers, as they can be easily routed to multiple devices and can control various parameters simultaneously.

How Does A Music Synthesizer Work?


Types of Oscillators

Oscillators are the heart of a music synthesizer, as they generate the raw sound waveform that can be shaped and manipulated to create different sounds. There are several types of oscillators commonly used in synthesizers, each with its own unique characteristics.

The most basic type of oscillator is the sine wave oscillator, which produces a pure and smooth tone. Other common types include the sawtooth oscillator, which has a rich and bright sound, the square wave oscillator, which has a hollow and punchy sound, and the triangle wave oscillator, which has a fuller and softer sound.

Waveform Generation

To create different sounds, synthesizers often allow users to manipulate the waveform generated by the oscillators. This can be done through various techniques such as waveform shaping, waveform modulation, and waveform synthesis.

Waveform shaping involves altering the amplitude, frequency, or phase of the waveform to achieve desired tonal characteristics. This can be done using voltage control amplifiers, filters, and modulation techniques.

Waveform modulation involves modulating the waveform with control signals to introduce harmonic or frequency changes. This can be achieved through techniques such as frequency modulation synthesis, where one oscillator modulates the frequency of another, resulting in complex and evolving sounds.

Waveform synthesis involves combining multiple oscillators or waveform sources to create more complex and rich sounds. This can be done through techniques such as additive synthesis, where multiple sine wave oscillators are layered together to create a harmonically rich sound.

How Does A Music Synthesizer Work?


Types of Filters

Filters are an essential component of synthesizers, as they shape and modify the frequency content of the sound. They allow users to control the brightness, warmth, and tonal character of the sound by selectively attenuating or boosting specific frequencies.

There are various types of filters commonly used in synthesizers, including low-pass filters, high-pass filters, bandpass filters, and notch filters. Each type of filter has its own specific frequency response and affect the sound in different ways.

Low-pass filters allow frequencies below a certain cutoff point to pass through, while attenuating frequencies above that point. High-pass filters do the opposite, allowing frequencies above the cutoff point to pass through, while attenuating frequencies below it.

Bandpass filters allow a specific range of frequencies to pass through, while attenuating frequencies outside of that range. Notch filters, on the other hand, attenuate a specific range of frequencies, while allowing frequencies outside of that range to pass through.

Frequency Modulation

One of the popular techniques used with filters in synthesizers is frequency modulation (FM). FM involves modulating the cutoff frequency of a filter with a control signal, such as another oscillator. This produces dynamic and evolving timbral changes in the sound, creating rich and complex textures.

By modulating the filter cutoff frequency using the output of another oscillator, the filter’s frequency response can be continuously altered, resulting in a wide range of tonal variations. This technique is widely used in FM synthesis, which is known for its ability to create metallic, bell-like, and evolving sounds.


Resonance is another important parameter of filters in synthesizers. It refers to the amplification of frequencies near the cutoff point, creating a more pronounced and accentuated response. The resonating frequencies can be controlled and manipulated to create different tonal effects.

Increasing the resonance of a low-pass filter, for example, can result in a more pronounced and nasally sound, often referred to as a “vocal” or “wah” effect. Resonance can also be used to create harmonic overtones and feedback-like effects, adding richness and complexity to the sound.

How Does A Music Synthesizer Work?


Voltage Control Amplifiers

Amplifiers in synthesizers are responsible for controlling the overall loudness or volume of the sound. Voltage control amplifiers (VCAs) are commonly used to dynamically adjust the amplitude of the sound signal.

VCAs are controlled by control voltage signals, which are typically generated by envelope generators or modulation sources. The control voltage determines the level of amplification or attenuation applied to the sound signal, allowing for dynamic control over the volume and dynamics of the sound.

Envelopes generators, which are often triggered by MIDI signals or control voltage sources, generate control voltages that control the amplitude of the sound over time. This allows users to shape the attack, decay, sustain, and release characteristics of the sound, resulting in a wide range of expressive and dynamic possibilities.

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Envelope Generators

Envelope generators are another important component in synthesizers, as they shape the temporal characteristics of the sound. They generate control signals called envelopes, which determine how the sound evolves over time.

An envelope typically consists of four stages: attack, decay, sustain, and release. The attack stage determines how quickly the sound reaches its maximum level, the decay stage determines how quickly the sound decays after reaching the maximum level, the sustain stage determines the level at which the sound remains as long as the key is held, and the release stage determines how quickly the sound fades out after the key is released.

By adjusting the parameters of the envelope generator, users can create a wide range of tonal variations and expressive effects. For example, a quick attack and release with a long sustain can produce a sharp and percussive sound, while a slow attack and release with a short sustain can create a smooth and pad-like sound.


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