3.1 Principles of subtractive synthesis
3 min read•july 22, 2024
is a powerful technique in electronic music. It starts with rich waveforms and uses filters to shape the sound. By removing specific frequencies, musicians can create a wide range of timbres and textures.
The process involves oscillators, filters, and envelopes. These components work together to generate, sculpt, and shape sounds over time. Understanding how they interact is key to mastering subtractive synthesis and creating unique sonic landscapes.
Fundamentals of Subtractive Synthesis
Fundamentals of subtractive synthesis
Top images from around the web for Fundamentals of subtractive synthesis
ADSR envelope | Libre Music Production View original
Is this image relevant?
Synthetic Biology: How to make an oscillator | eLife View original
Is this image relevant?
Synthesizer - Wikipedia View original
Is this image relevant?
ADSR envelope | Libre Music Production View original
Is this image relevant?
Synthetic Biology: How to make an oscillator | eLife View original
Is this image relevant?
1 of 3
Top images from around the web for Fundamentals of subtractive synthesis
ADSR envelope | Libre Music Production View original
Is this image relevant?
Synthetic Biology: How to make an oscillator | eLife View original
Is this image relevant?
Synthesizer - Wikipedia View original
Is this image relevant?
ADSR envelope | Libre Music Production View original
Is this image relevant?
Synthetic Biology: How to make an oscillator | eLife View original
Is this image relevant?
1 of 3
- Subtractive synthesis starts with harmonically rich waveforms (sawtooth, square, pulse) generated by oscillators
- Filters remove or attenuate specific frequencies from the original waveform to achieve the desired sound
- Low-pass filters attenuate high frequencies while allowing low frequencies to pass through
- High-pass filters attenuate low frequencies and allow high frequencies to pass
- Band-pass filters allow a specific range of frequencies to pass while attenuating those outside the range
- Envelopes ( - , , , ) shape the volume and of the sound over time
- Attack determines how quickly the sound reaches its maximum level
- Decay sets the time for the sound to drop from the peak level to the sustain level
- Sustain defines the level at which the sound remains as long as a key is held
- Release determines how long it takes for the sound to fade out after the key is released
Components in subtractive synthesis
- Oscillators generate the initial waveforms that serve as the foundation for subtractive synthesis
- Multiple oscillators can be used to create more complex timbres
- Oscillators offer various waveform shapes (sawtooth, square, triangle, pulse)
- Filters sculpt the frequency content of the waveforms generated by the oscillators
- Common types include low-pass, high-pass, and band-pass filters
- Filters have parameters like and that determine their effect on the sound
- Envelopes control how the sound evolves over time, shaping its volume and timbre
- The most common envelope is the ADSR (Attack, Decay, Sustain, Release)
- Envelopes can be applied to various parameters ( volume, filter cutoff frequency)
- Additional components (LFOs - Low-Frequency Oscillators, sources) add movement and variation to the sound
- LFOs can modulate parameters like pitch, volume, or filter cutoff to create effects (vibrato, tremolo)
Subtractive Synthesis in Practice
Waveform sculpting with filters
- Harmonically rich waveforms (sawtooth, square) contain a fundamental frequency and a series of
- Sawtooth waves have all harmonics present, with amplitudes decreasing as the harmonic number increases
- Square waves have only odd harmonics present, with amplitudes decreasing as the harmonic number increases
- Filters remove or attenuate specific frequencies from these harmonically rich waveforms to shape the timbre
- Low-pass filters create warm, mellow timbres by attenuating high frequencies
- Increasing the cutoff frequency of a results in a brighter sound with more high-frequency content
- High-pass filters create thin, bright timbres by attenuating low frequencies
- Band-pass filters emphasize a specific range of frequencies, creating unique, focused timbres
- Low-pass filters create warm, mellow timbres by attenuating high frequencies
- Resonance (Q) is a filter parameter that emphasizes frequencies around the cutoff point
- High resonance values create a distinctive, "whistling" quality at the cutoff frequency
- Adjusting filter parameters and envelope settings allows for the creation of a wide variety of timbres from a single harmonically rich waveform
Subtractive synthesis in analog synthesizers
- Classic analog synthesizers (Moog , Sequential Circuits ) heavily relied on subtractive synthesis
- These synthesizers featured multiple oscillators, filters, and envelopes to create rich, dynamic timbres
- Oscillators in classic analog designs offered a selection of waveforms (sawtooth, square, triangle)
- Some synthesizers (Minimoog) included oscillator sync and frequency modulation options for additional timbral possibilities
- Filters played a crucial role in shaping the sound of these synthesizers
- The Minimoog's distinctive 24 dB/oct low-pass filter, with its smooth, musical resonance, became a defining characteristic of its sound
- The Prophet-5's filter section offered low-pass and high-pass filters, allowing for more complex timbral shaping
- ADSR envelopes shaped the volume and timbre of the sound over time
- Envelopes were often routed to control filter cutoff frequency, creating dynamic, evolving timbres
- The hands-on, intuitive interface with dedicated knobs and sliders for each parameter made subtractive synthesis accessible and expressive
- The limitations of analog circuitry and the need for efficient sound design contributed to the widespread use of subtractive synthesis in these classic instruments
Key Terms to Review (26)
ADSR: ADSR stands for Attack, Decay, Sustain, and Release, which are the four stages of an envelope that shape how a sound evolves over time. This envelope controls the amplitude of a sound and significantly influences its timbre and expressiveness. By adjusting each stage of the ADSR envelope, musicians can create various dynamic sounds, enhancing the emotional impact of their music.
Attack: In music production, attack refers to the initial phase of a sound's envelope, specifically the speed at which the sound reaches its peak level after being triggered. The attack time influences how a sound is perceived in terms of its immediacy and character, affecting everything from the punchiness of a drum hit to the articulation of a synth note. A quick attack can create a sharp and defined sound, while a slower attack can result in a more gradual onset that softens the impact.
Audio Path: The audio path refers to the route that an audio signal takes from its source to its output in a sound synthesis or processing environment. This includes all the components the signal passes through, such as oscillators, filters, effects processors, and mixers, which shape and transform the sound throughout the process. Understanding the audio path is crucial for effectively managing sound design and synthesis techniques.
Band-pass filter: A band-pass filter is an electronic filter that allows signals within a specific frequency range to pass through while attenuating frequencies outside that range. This filtering process is crucial in sound synthesis and manipulation, as it helps shape the tonal qualities of a sound by emphasizing certain frequency bands and reducing others, which connects directly to subtractive synthesis techniques, oscillator and filter interactions, and both analog and digital signal processing.
Cutoff frequency: Cutoff frequency refers to the specific frequency at which a filter begins to attenuate the amplitude of a signal. It serves as a critical parameter in shaping sound in synthesis, particularly in subtractive synthesis, where it defines the boundary between frequencies that are allowed to pass through a filter and those that are reduced or eliminated. Understanding cutoff frequency is essential for manipulating the tonal quality of sounds, as it directly impacts how oscillators generate harmonics and how envelopes control the behavior of these frequencies over time.
Decay: In sound synthesis, decay refers to the phase of a sound's envelope where the amplitude decreases after the initial peak, shaping the sound's overall character. This reduction in volume is a crucial element in crafting a sound's dynamics and can influence the emotional impact of music. Decay is often linked with how oscillators produce tones, how filters shape frequencies, and how envelopes control the dynamics of sounds over time.
Envelope Generator: An envelope generator is a component in synthesis that shapes the amplitude of a sound over time, typically controlling how the sound evolves from the moment a note is played until it stops. It defines key aspects of a sound's dynamics, such as attack, decay, sustain, and release (ADSR), which are crucial for creating expressive sounds in various synthesis methods. Envelope generators can be found in subtractive synthesis, integrated into analog synthesizer architecture, and utilized in various forms of synthesis like FM and additive synthesis.
Filter: A filter is a tool used in audio processing to manipulate the frequency content of a sound by allowing certain frequencies to pass through while attenuating others. In synthesis, filters play a crucial role in shaping timbre and texture, enabling musicians to create a wide range of sounds by altering harmonics. They can be applied to various synthesis methods, affecting how the sound is perceived and providing control over resonance and cutoff frequency.
Harmonics: Harmonics are specific frequencies that occur at integer multiples of a fundamental frequency. They play a crucial role in shaping the timbre of sounds, as they contribute to the richness and complexity of musical tones. Understanding harmonics is essential for manipulating sound in various synthesis techniques, as they influence how we perceive pitch and tone color, directly impacting frequency, amplitude, and timbre.
High-pass filter: A high-pass filter is an audio processing tool that allows signals with a frequency higher than a certain cutoff frequency to pass through while attenuating (reducing) the amplitude of frequencies lower than the cutoff. This makes it essential in shaping sound by removing unwanted low-frequency noise and enhancing clarity, especially in the context of synthesis, sampling, and mixing.
Layering: Layering is a music production technique that involves combining multiple sounds or musical elements to create a richer, more complex sonic texture. This technique allows producers to enhance the depth and impact of their compositions by blending different instruments, samples, or sound sources together in a way that complements each other.
LFO - Low-Frequency Oscillator: A low-frequency oscillator (LFO) is an electronic signal generator that produces waveforms at frequencies lower than the audible range, typically below 20 Hz. LFOs are widely used in subtractive synthesis to modulate parameters of sound, like pitch, filter cutoff, or amplitude, creating dynamic and evolving textures. By applying LFO modulation, sound designers can introduce movement and complexity to their patches, making static sounds more engaging.
Low-pass filter: A low-pass filter is an audio processing tool that allows frequencies below a certain cutoff frequency to pass through while attenuating (reducing) higher frequencies. This technique is essential in shaping sound by removing unwanted high-frequency content, thus allowing for smoother, warmer tones and creating depth in the mix.
Minimoog: The minimoog is a classic analog synthesizer that was first introduced in 1970 and is renowned for its role in the development of electronic music. It features a compact design and is primarily based on subtractive synthesis, allowing musicians to create a wide range of sounds by shaping the timbre of oscillators using filters and modulation. Its signature sound has made it a staple in various genres, including rock, jazz, and electronic music.
Modulation: Modulation is the process of varying a parameter in a sound signal, typically involving changes in pitch, amplitude, or timbre over time. This technique is crucial for creating movement and interest in music, as it allows for shifts in dynamics and color, enhancing the emotional impact of a composition.
Oscillator: An oscillator is a device or circuit that generates a periodic waveform, typically in the form of an audio signal. In the realm of sound synthesis, oscillators serve as the foundation for creating and manipulating sound waves, often producing various waveforms like sine, square, triangle, and sawtooth. The output of an oscillator can be shaped and transformed through different synthesis techniques, modulation methods, and signal processing, making it a crucial component in sound design.
Prophet-5: The Prophet-5 is a revolutionary polyphonic synthesizer developed by Dave Smith Instruments and released in 1978. It is one of the first programmable polyphonic synthesizers, known for its rich sound and the ability to store and recall presets, which paved the way for modern synthesizers. The Prophet-5 utilizes subtractive synthesis, allowing users to shape sound by filtering harmonically rich waveforms.
Release: In music production, release refers to the time it takes for a sound to fade away after the note has been played or the trigger has stopped. It plays a critical role in shaping the overall character of sounds, influencing how they feel and interact with other elements in a mix.
Resonance: Resonance is the phenomenon where an object or system amplifies certain frequencies due to its natural vibrational modes. This concept is fundamental in sound and music production, as it influences how sounds are shaped and perceived. It plays a crucial role in defining timbre, enhancing specific frequencies in oscillators, and creating rich textures in synthesis methods and mixing techniques.
Roland Juno-106: The Roland Juno-106 is a classic analog synthesizer known for its warm sounds and user-friendly interface. Released in the early 1980s, it utilizes subtractive synthesis to create a wide range of musical tones, making it a popular choice among electronic music producers and musicians. The Juno-106 features six voices of polyphony and an onboard chorus effect, contributing to its rich sonic character.
Signal Chain: A signal chain is the path that an audio signal follows from its source to its output, encompassing various processing elements along the way. This can include devices like microphones, effects processors, mixers, and speakers, each playing a critical role in shaping the sound. Understanding the signal chain is essential for manipulating audio in subtractive synthesis, as it impacts how sound is created and altered through various processes.
Sound Sculpting: Sound sculpting is the process of shaping and refining audio to create unique sounds through various techniques, particularly in electronic music. This practice involves manipulating sound waves using tools like synthesizers, effects processors, and equalizers to achieve desired sonic qualities and textures. Sound sculpting is essential for developing a signature sound and enhances the overall expressiveness of musical compositions.
Subtractive synthesis: Subtractive synthesis is a sound synthesis technique that starts with a rich, harmonically complex waveform and shapes the sound by removing (or subtracting) certain frequencies using filters. This approach allows for the creation of a wide range of sounds by altering the harmonic content, which is fundamental to electronic music production and sound design.
Sustain: Sustain refers to the duration a sound maintains its presence after being initiated, particularly in electronic music. This concept is crucial as it affects how notes are perceived over time, influencing the character of melodies and harmonies. It can determine how long a sound lasts before fading away or being cut off, thus shaping the overall texture and emotional impact of a composition.
Timbre: Timbre is the quality or color of sound that distinguishes different types of sound production, such as musical instruments or voices, even when they produce the same pitch and loudness. It is influenced by various factors like the harmonic content, envelope, and dynamics of a sound, which helps us identify different sounds in music and audio.
Waveform shaping: Waveform shaping is the process of altering the harmonic content and overall shape of a waveform to create desired sounds in electronic music synthesis. This technique allows for the modification of a sound's timbre by adjusting its spectral characteristics, making it a crucial aspect of various synthesis methods. By employing techniques like filtering and modulation, waveform shaping can dramatically change the sonic qualities of a sound source, allowing for rich and complex textures in music production.