How Software Sound Synthesis Works

Last Updated:

Digital audio production has come a long way, thanks to software sound synthesis. This technology is crucial for musicians and sound designers in the modern day. It lets them create detailed sounds that were once impossible to achieve.

At its core, this process involves generating and changing waveforms digitally, as opposed to through analog electrical components.

The beauty of software sound synthesis is that it can be used to emulate analog sounds, while opening up new worlds of sound design no possible with traditional equipment.

Software synthesis also gives us a high degree of precision and control to manipulate audio signals however we want. The sky is truly the limit, and in this guide, you’ll get an overview of exactly how everything works and the various forms of software synthesis out there.

Software Based Sound Synthesis Fundamentals

Making sound is all about generating audio waveforms – simple sound shapes like sine, square, sawtooth, and triangle waves. These are the basics for making more complex sounds.

Sound designers then use tools like modulators, filters, envelopes and effects to shape those waveforms into the sounds you hear in most modern music today.

This can be done on a computer or mobile device and does not require any physical equipment (as opposed to analog/hardware synthesis) other than a sound output device.

The various types of synthesis methods can all be emulated using software. This is why it’s such a versatile approach to generating and designing sounds.

The General Framework

Below are the general concepts and steps you’ll need to be familiar with in order to create your own instruments and sounds using digital software.

Of course, if you just want to make music, let others do the hard work of developing software synthesizers and you can just use the fruits of their labor.

Main Concepts in Sound Synthesis to Know:

  1. Sound Synthesis: This is the process of generating sound, using various methods like subtractive, additive, granular, physical modeling, FM synthesis etc.
  2. Oscillators: These generate the initial sound (i.e. waveforms) in a synthesizer, which is then shaped and modified by the other components.
  3. Waveforms: The basic building blocks of any sound, including sine waves, square waves, sawtooth waves, and noise.
  4. Filters: These are used to control which sound frequencies are heard, and at what levels. This is how you shape your sound.
  5. Envelopes: These are used to control how a sound plays back – the attack, decay, sustain, and release (ADSR) of a sound.
  6. Modulation: This is used to dynamically change the characteristics of a sound over time, using things like LFOs (low frequency oscillators) and envelopes.
  7. MIDI: This is a protocol that allows electronic musical instruments, computers and other related devices to communicate with each other. Midi controllers let you play a software synth just like a real instrument.
Synth Part Diagram

The Technical Side

Software synthesis generates audio signals by using algorithms to produce a sequence of numbers. These numbers represent the variations in air pressure that would be created by the sound wave in the natural world.

This sequence of numbers is represented in binary form (1s and 0s) that the computer can understand.

The process starts with a digital signal processor (DSP) which is a specialized microprocessor that manipulates digital signals to produce the desired sound. The DSP uses mathematical functions to generate waveforms like sine waves, square waves, or complex modulations.

The generated binary data (1s and 0s) is then sent to a digital-to-analog converter (DAC). The DAC converts the binary data into an analog signal that can be amplified and sent to a speaker. The speaker then vibrates according to the analog signal, creating sound waves that we can hear.

The conversion from digital to analog involves a process called sampling. The DSP takes samples of the audio signal at a specific rate (typically 44.1 kHz for CDs). Each sample represents the amplitude (height/strength) of the sound wave at a specific point in time.

The DAC then reconstructs the original waveform from these samples.

Steps Involved in Software Synthesis Development:

  1. Define the Purpose: Determine what kind of sounds you want the synthesizer to produce. This could be anything from simple waveforms to complex layered sounds.
  2. Choose the Platform: Decide whether you want to create a standalone synth or a plugin for existing music software. This will determine the programming language and development tools you need to use.
  3. Learn the Required Programming Language: If you don’t already know it, you will need to learn the programming language that your chosen platform uses. This could be C++, Python, or another language.
  4. Understand Digital Signal Processing: Synthesizers work by manipulating digital audio signals. To create your own, you’ll need to understand how this works. This might involve studying university-level math and engineering concepts.
  5. Develop the User Interface: Decide what controls you want the synth to have, and design an interface that lets users manipulate those controls. This might involve sliders, knobs, buttons, and other graphical elements.
  6. Implement the Signal Processing: Write the code that takes the user’s input and turns it into sound. This is the heart of the synthesizer.
  7. Test the Synthesizer: Make sure your synth works as intended. This might involve debugging your code, tweaking the sound, and making sure the user interface is intuitive and responsive.
  8. Optimize the Performance: Synthesizers need to process audio in real time, which can require LOTS of computing power. You may need to optimize your code to make sure it runs smoothly on various systems.


Digital Sound Manipulation Techniques

Digital sound techniques have made it easy to change and transform audio signals. These tricks are not only key in creating modern music but are also used in many things like sound design, movie scores, and multimedia arts.

These methods use advanced steps that help music makers and sound engineers shape sound exactly how they want.

At the heart of these techniques is spectral analysis. This is a way to get a detailed look at a sound’s structure. By looking at the frequency spectrum, artists can focus on, boost, or lessen certain parts of a sound. This creates sound textures that were once hard to achieve.

This approach is basic in reducing noise, correcting pitch, and making dreamlike sounds.

Being able to process sound in real-time has changed the field. It gives immediate sound feedback as changes are made. This is important in live shows and interactive installations, where changing the audio is part of the experience.

Interactive platforms have appeared, linking the technical with the creative. These easy-to-use platforms give artists the power to change sound in natural and expressive ways, often with just a swipe or a turn of a knob.

Spectral Analysis in a Synth

Techniques Breakdown

In the world of software that makes sounds, we’re seeing more and more new techniques. These include Vector, Physical Modelling, Physics Based, Numerical, Modal Sound Synthesis and more.

Each technique has its own unique benefits and opens up new ways to create sound. This lets those who create music and sound effects make even more intricate and lifelike audio.

It’s vital for music pros to keep up with these growing tech trends if they want to stay on top in the world of digital sound making.

Vector Synthesis

Vector synthesis is a cool new way to make sounds on a computer. It changes sound by blending different sounds together.

People use vector synthesis for many things. It’s great for making music and creating sound effects for video games and virtual reality.

When you compare different vector synthesis programs, you’ll see they’re not all the same. They look different and they make sounds in different ways. But they all let you design unique sounds.

Musicians like to use vector synthesis to create sounds that change and move around. This makes their music more interesting and exciting.

Vector synthesis is also fun to use in live performances. It lets musicians change their sounds while they’re playing, which really grabs the audience’s attention.

Learn more about Vector Synthesis and how it works.

Physical Modelling Synthesis

Vector synthesis improvement led to a new type of software synthesizer technology – physical modelling synthesis. It uses math to copy the real-life qualities of acoustic instruments. This method gives a detailed imitation of instruments, making digital ones behave like their acoustic versions.

Physical modeling has more uses than just regular synthesis. It provides simulations that change based on how the performer is playing. The techniques used in physical modeling synthesis are smart. They use formulas that can recreate the vibrations of strings, the sound of wood, or the hum of a reed.

Learn more about Physical Modeling Synthesis and how it works.

Physics Based Synthesis

Physics-based sound synthesis is an exciting new area in synthesizer software. It uses the laws of physics to make realistic and complex sounds. Instead of just using the usual methods, it also uses simulations of real-world acoustics and physical interactions. This makes virtual instruments sound even more real.

Professionals who design sounds use this advanced method. They can simulate the vibrations and echoes of real objects and places. This results in sounds that are full of texture and change in interesting ways.

Because of physics-based sound synthesis, synthesizer software can now make almost any sound you can think of. This is because it uses simulations of physical forces to shape the sound.

Numerical Sound Synthesis

Numerical sound synthesis uses math to create complicated sound waves that are precise and versatile. It mostly uses a method called algorithmic composition, which lets music makers create sounds that follow mathematical rules but are still expressive in a musical way.

This method also allows for real-time processing, which means that music makers can listen to and interact with the sounds they’re working on as they make them. Some techniques, like spectral analysis, break down sound into its basic parts, or frequencies. This gives music makers a lot of control over the different parts of sound.

Modal Sound Synthesis

There are two types of digital/software synthesis: numerical (described above) and modal. Numerical relies on math formulas to create waveforms, while modal uses the physical qualities of materials to mimic real-world sounds.

Modal sound synthesis is like making a model of how things shake or vibrate. Each vibration has a unique frequency and decay rate, making a unique sound. By manipulating these vibrations, we can create a wider range of sounds.

Additionally, machine learning, a type of artificial intelligence, is helping to make this process better. It allows us to more accurately and efficiently mimic real-world sounds.

Spatial Sound Synthesis

Spatial sound synthesis is a method used in software technology that mimics how sound behaves in a 3D space. This technique makes environments feel more real by using special audio techniques that manipulate 3D sound.

In simple terms, spatial audio processing lets sound designers and music makers place sounds in a virtual space. This gives listeners a very real sound experience. By controlling where the sound comes from, how far it travels, and how it moves, spatial sound synthesis can copy real-world sounds or create entirely new soundscapes.

It’s important because it helps create the illusion of space and where the sound is coming from, which makes the user feel more immersed.

SkyDust Spatial Synth Software

Contact Sound Synthesis

Contact Sound Synthesis uses the ideas of spatial sound making but adds more to it. It’s all about creating sounds that mimic real objects touching each other. This is really important for making virtual instruments feel more real and interactive.

In simple terms, this means sound designers can use certain rules to create sounds that are very detailed. For example, they can make a sound that is just like a drumstick hitting a cymbal or fingers plucking a guitar string. This makes the virtual instrument sound more real and lively.

Contact Sound Synthesis also lets people experiment with sound. This means composers can try out new sounds that go beyond what we usually hear in music. It’s a great way to push music creation into new areas.

Cellular Sound Synthesis

Cellular Sound Synthesis is a new approach in the field of software synthesizer technology. It uses cellular automata principles to create evolving and intricate sounds. This method is similar to organic synthesis, as it copies natural growth patterns to produce sound.

The process works by shaping sound through cellular automation. Here, each sound unit, or ‘cell’, works based on set rules. This leads to emerging, changing compositions. This algorithm-based composition method makes sure every sound event adds to the overall texture and promotes harmonic resonance.

Concatenative Sound Synthesis

Concatenative Sound Synthesis builds complex sounds by using small pieces of existing audio. This method uses a technique called granular synthesis. This lets us process and change small bits of sound in real time to make new sound colors and textures.

Spectral analysis is very important in this process. It gives us the data we need to find and use these audio pieces effectively. Concatenative synthesis is part of a larger field called algorithmic composition. Here, composers use this method to create soundscapes and musical parts using a computer program.

It also makes live performances more interactive. It lets musicians put together sounds on the fly in response to live input. This bridges the gap between pre-recorded audio and spontaneous creativity.

Acoustic Modeling Synthesis

Acoustic Modeling Synthesis makes sounds by copying the real-world qualities of instruments and rooms.

It helps us make virtual tools that sound just like the real ones because it uses detailed sound simulations. This is great for live applications where quick response and interaction are important.

This method can use techniques like waveguide synthesis, which copies the vibrations in real instruments.

AI sound synthesis

AI sound synthesis uses artificial intelligence to make complex sounds and musical textures. It gives great control and variety. This method also includes music made by AI.

Here, algorithms can write new songs or copy existing styles. Machine learning plays a key role in this music. It lets systems study lots of songs and styles to make new ones. These compositions from neural networks aren’t just for fun. They have real uses in making music automatically. This gives lots of material for different media.

AI-powered tools for composers are changing the music industry. They help producers and composers use smart software for creative help. They also push the limits of usual sound design.

Learn more about AI Sound Synthesis and how it works.

History and Evolution

Let’s take a look at the history of software synthesis and how it’s changed over time.

We’ll check out new ideas and technical progress that have changed software sound synthesis over the years. From simple early computer music methods to the fancy ways of creating sounds we have today, this part gives you a detailed view of how software sound synthesis has changed.

Early History

Traditionally, sound has been synthesized through analog electrical circuits. An oscillator would generate a waveform using electricity. The signal that was generated would then pass through other electrical components, coloring and shaping it’s overall sound.

Software sound synthesis started in the early 1950s with the development of MUSIC, the first widely-used program for sound synthesis, by Max Mathews at Bell Labs in 1957.

This new form of synthesis used digital software – computer code, math formulas and algorithms – to mimic or create new sounds.

As technology advanced, so did the complexity and capabilities of software sound synthesis.

In the 1960s, a new generation of synthesis software was introduced, including the groundbreaking Music V, also developed by Max Mathews. This software introduced the concept of unit generators, which allowed for more complex and varied sounds to be created.

Then in the 1980s, the rise of personal computers led to the development of more user-friendly and accessible sound synthesis software. This era saw the introduction of MIDI (Musical Instrument Digital Interface), a technology that revolutionized the music industry by allowing different electronic instruments and computers to communicate with each other.

Max Matthews
Max Matthews

Academic Institutions’ Contributions

Artists and companies have done a lot to evolve the science of sound synthesis. But schools and research places have also made big leaps in this field. They’ve played a key role in many ways.

For example, they’ve joined forces with other institutions, sharing knowledge and resources to push forward in sound synthesis research. Colleges have teamed up with electronic music centers like IRCAM in Paris, leading to big tech breakthroughs. This boosts the power of software synthesis and digital sound changes.

Education programs are also key in these institutions. They’ve helped to grow talent and encourage new ideas in this field. Classes on electronic music production have given new musicians and sound engineers the tools to make new and better sound synthesis. The research often turns into real-world use, making new synthesis ways and improving old ones.

Tech growth from these academic places has changed the face of electronic music. For instance, the creation of Music 5 and Music 11 software systems for computer sound synthesis in schools has paved the way for modern software synthesizers.

Through all these efforts, schools and research places keep the field of sound synthesis alive and exciting. They constantly push the limits of music production and performance. Their dedication to research, learning, and invention continues to add to the range of sounds available to artists and listeners.

Influential Pioneers in Synthesis

Max Mathews is a key figure in the history of sound creation. He did some ground-breaking work at Bell Labs in the 1950s and 60s. He developed the MUSIC series of programming languages. These were game-changing innovations in the field. His research proved that computers can create sounds and music. This changed how we think about and make sound.

Other pioneers of the field include:

  1. Barry Vercoe: Barry Vercoe is a computer scientist who created the Music11, a music synthesis system which was a predecessor to his later creation, the Csound system. Csound is a powerful open-source software synthesis tool that is used by musicians and researchers worldwide.
  2. Miller Puckette: Known for creating Pure Data and Max/MSP, two widely used real-time graphical dataflow programming environments, Miller Puckette’s contributions to software synthesis are highly influential. His work allows musicians to build their own software synthesizers and effects processors.
  3. Carla Scaletti: Carla Scaletti is the designer of the KYMA sound design language. She has contributed to the development of software synthesis through her work with Symbolic Sound Corporation, a company that she co-founded.
  4. Pierre Boulez: Known more for his work as a composer and conductor, Pierre Boulez’s contributions to software synthesis come in the form of the IRCAM institute in Paris, which he founded. The institute has been a major center for research and development in music and sound technology, including software synthesis.
  5. Paul Lansky: Paul Lansky is a pioneer in the field of computer music. He used computer algorithms to synthesize sound and composed many pieces of music using these techniques. Lansky’s work opened up new possibilities for software synthesis.
  6. Dave Smith: Dave Smith is known for designing the Prophet-5, one of the first fully programmable polyphonic synthesizers. He also co-developed the MIDI protocol, a standard for transmitting musical information between digital instruments, which played a major role in the development of music software including software synthesis.
  7. Karlheinz Stockhausen: Stockhausen was a key figure in the development of electronic music and his works often involved complex software synthesizers. His influence helped to bring software synthesis into the mainstream.

What to Do Next

Thanks for reading this complete guide on Software-Based Sound Synthesis for beginners. Next up, deep-dive into another area you’d like to learn about: