Synthesis is the art of creating sound from scratch using electronic signals or algorithms. Instead of recording a real instrument, you generate waveforms and sculpt them into the exact sound you want.
All synthesis starts with an oscillator — an electronic signal that produces a repeating waveform. Change the waveform shape, filter it, modulate it with other signals, and you create an infinite variety of sounds.
Subtractive synthesis begins with a harmonically rich waveform (saw, square, triangle) and removes frequencies using a filter. This is the most intuitive synthesis method and the foundation of classic analog synths.
Think of it like sculpting: you start with a block of stone (complex waveform) and carve away (filter) to reveal the shape you want. The Moog Minimoog and Roland Juno-106 are icons of subtractive synthesis.
Additive synthesis constructs complex sounds by combining many individual sine waves, each at different frequencies and amplitudes. It's based on Fourier's theorem: any periodic sound can be decomposed into sine waves.
Most real-world sounds (voices, instruments) are additive — they contain many frequencies simultaneously. Additive synthesis mimics this natural behavior by starting from simplicity (sine waves) and building complexity.
FM (Frequency Modulation) synthesis uses one oscillator to modulate another's frequency. The modulating signal creates sidebands — additional frequencies that add harmonic or inharmonic complexity.
FM produces bright, glassy, metallic sounds impossible with subtractive synthesis alone. The Yamaha DX7 made FM famous in the 1980s — its electric piano and bass sounds defined the decade's pop and synth-pop.
Synthesis Types Compared
| Type | How It Works | Best Sounds | Example Synths | Learning Curve |
|---|---|---|---|---|
| Subtractive | Complex waveform + resonant filter | Leads, pads, bass, plucks | Minimoog, Juno-106, Serum | Easy |
| Additive | Many sine waves summed together | Organs, choral, realistic tones | Reason's Thor, custom tools | Medium |
| FM | Oscillator modulates another's frequency | Electric pianos, bells, glass, metallic | FM8, Operator, Dexed | Medium-Hard |
| Wavetable | Cycles through tables of single-cycle waveforms | Evolving pads, digital textures, Reese bass | Serum, Massive, Wavetable | Easy-Medium |
| Granular | Micro samples rearranged and layered | Ambience, glitch, textures, sci-fi | Clouds, Grain, Ableton Wavetable | Hard |
Design Your First Sound in 5 Steps
- 1. Pick a Synthesis Type Decide what sound you want: warm analog feel → subtractive. Bright metallic tones → FM.Evolving textures → wavetable or granular. Start with subtractive if you're new.
- 2. Choose Your Oscillator Waveform In subtractive synthesis, start with a saw wave for bright harmonics or a square wave for hollow, woody tones. Add a sub-oscillator (sine wave one octave below) for weight.
- 3. Shape With a Filter Route the oscillator through a low-pass filter. Set the cutoff frequency to start high, then sweep it down. Add resonance to emphasize frequencies near the cutoff for classic synth character.
- 4. Add Modulation Use an LFO (Low Frequency Oscillator) to modulate the filter cutoff or pitch for movement. Try a slow triangle-wave LFO on filter cutoff for a classic 'wobble' or 'filter sweep' effect.
- 5. Shape the Amplitude Envelope Use an ADSR envelope on the gain/VCA to control how the sound evolves over time. Quick attack + short decay = pluck. Slow attack + long sustain = pad. The envelope defines the sound's personality.
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Browse Free DownloadsSound Design: Common Questions
- What synth is best for beginners learning synthesis?
- Vital (free) or Serum ($189) are the best starting points because they combine all synthesis types in an intuitive interface with visual feedback. You can see the waveforms, filters, and envelopes as you manipulate them, building intuition faster than hardware.
- What's the difference between wavetable and subtractive synthesis?
- Subtractive starts with harmonically rich waveforms and removes frequencies with filters. Wavetable uses a series of single-cycle waveforms (tables) that can be morphed or scanned progressively, creating evolving timbres that subtractive filters alone cannot achieve.
- Why does FM synthesis sound so bright and metallic?
- When one oscillator modulates another's frequency at audio rates (above 20 Hz), it creates sideband frequencies that are mathematical sums and differences of the carrier and modulator. These sidebands can extend far above the fundamental, creating the bright, inharmonic overtones characteristic of FM.
- Do I need a hardware synth to learn sound design?
- No — software synths are more accessible and equally powerful for learning. Vital, Serum, Massive, and Operator (Ableton) cover every major synthesis type. Hardware adds tactile knobs and workflow friction that some find inspiring, but it's not required.
- How do I make my sounds less generic?
- Layer different synthesis types (e.g., subtractive bass + FM sub-harmonic). Process with analog-modeled saturation and compression. Automate parameters over time. Resample and repitch sections. The key is to combine techniques rather than relying on presets alone.