13.2 Sound Synthesis and Processing Techniques

Sound synthesis and processing are the building blocks of modern music production. From additive to granular synthesis, these methods shape raw waveforms into complex sounds. Filters, effects, and modulation techniques further sculpt these sounds, creating unique textures and atmospheres.

Layering techniques and parameter automation bring depth and movement to sound designs. By analyzing and deconstructing complex sounds, we can identify the synthesis methods and processing techniques used. This knowledge empowers us to recreate and innovate in our own sound design projects.

Sound Synthesis Methods

Types of sound synthesis

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  Simple FM Synth View original

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  Wavetable synthesis - Wikipedia View original

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• Additive synthesis combines simple waveforms (sinusoids) to create complex sounds, with each waveform representing a partial or harmonic, allowing precise control over the frequency spectrum
• Subtractive synthesis starts with a harmonically rich waveform (sawtooth, square) and filters out unwanted frequencies to shape the sound, commonly used in analog synthesizers (Moog, Roland)
• Frequency modulation (FM) synthesis modulates the frequency of a carrier oscillator with a modulator oscillator, creating complex, dynamic timbres useful for metallic, bell-like, or percussive sounds (Yamaha DX7)
• Wavetable synthesis stores and plays back pre-recorded or generated waveforms, allowing for smooth transitions between different waveforms and offering a wide variety of timbral possibilities (PPG Wave, Korg Wavestation)
• Granular synthesis splits audio into small pieces called "grains" and manipulates and recombines them to create new textures, enabling time-stretching, pitch-shifting, and unique soundscapes (Reaktor, Max/MSP)
• Physical modeling synthesis simulates the physical properties and behavior of real instruments using mathematical models to emulate acoustic sounds, providing realistic and expressive instrument sounds (Yamaha VL1, Pianoteq)

Sound Processing Techniques

Filters and modulation techniques

• Filters
  • Low-pass filter attenuates frequencies above a cutoff point, creating a darker or muffled sound
  • High-pass filter attenuates frequencies below a cutoff point, creating a brighter or thinner sound
  • Band-pass filter allows a specific range of frequencies to pass through, isolating certain frequency bands
  • Notch filter removes a specific range of frequencies, useful for reducing unwanted resonances or noise
• Effects
  • Reverb simulates the acoustic properties of a space, adding depth and atmosphere to a sound (plate, hall, room)
  • Delay creates echoes or repeating patterns, useful for thickening a sound or creating rhythmic effects (slapback, ping-pong)
  • Distortion adds harmonic content and creates a "fuzzy" or "gritty" sound, commonly used in rock and electronic music (overdrive, fuzz)
  • Chorus simulates multiple voices or instruments playing together, creating a thicker and more lush sound (ensemble, unison)
  • Flanger creates a sweeping, whooshing, or metallic sound by mixing a delayed signal with the original (jet plane, spaceship)
• Modulation
  • Amplitude modulation (AM) varies the volume of a sound over time, creating tremolo or gating effects
  • Ring modulation multiplies two audio signals, creating new frequencies and a metallic or clangorous sound
  • Tremolo is rapid amplitude modulation, creating a pulsating effect (vintage guitar amps, organ)
  • Vibrato is periodic pitch variation, simulating the effect of vocal or instrumental vibrato (string instruments, synthesizers)

Creation of unique sound textures

• Layering multiple synthesis techniques combines different synthesis methods to create complex, hybrid sounds (additive + FM, subtractive + wavetable)
• Applying effects and modulation to synthesized sounds processes them with filters, effects, and modulation techniques, experimenting with effect parameters and modulation depths to create unique timbres
• Resampling and further processing involves recording and capturing the output of synthesized and processed sounds, using the recorded samples as a basis for further manipulation and layering
• Automating synthesis and processing parameters creates dynamic and evolving sound textures by automating parameter changes over time, using envelopes, LFOs, and step sequencers to control synthesis and processing parameters

Analysis of complex sound designs

• Identifying synthesis methods involves listening critically to complex sounds and trying to identify the synthesis techniques used, recognizing characteristics of different synthesis methods (harmonically rich subtractive synthesis, metallic FM tones)
• Recognizing effects and processing techniques analyzes how effects and processing techniques contribute to the overall sound, identifying the use of filters, reverb, delay, distortion, and modulation in sound designs
• Breaking down layered and hybrid sounds deconstructs complex sound designs into individual components, identifying the different layers and elements that make up the sound and determining how they interact and contribute to the final texture
• Recreating and reverse-engineering sound designs attempts to recreate complex sound designs using identified synthesis and processing techniques, experimenting with different combinations and parameters to closely match the original sound, using the knowledge gained from analysis to inform future sound design decisions