How to Design Synth Sounds from Scratch: A Step-by-Step Guide

Synthesizers are incredibly powerful tools for musicians and sound designers. They allow you to create everything from bass-heavy grooves to shimmering pads, glitchy effects, and more. But if you’ve ever opened a synth plugin and been overwhelmed by the knobs, sliders, and waveforms, you’re not alone. Learning to design synth sounds from scratch might seem daunting, but with a solid understanding of the fundamentals, you’ll soon be crafting custom sounds tailored to your unique needs.

Here’s a step-by-step guide to help you get started.

1. Understand the Basics of Sound Waves and Synthesis

Before diving into the synthesizer’s interface, it’s helpful to have a basic understanding of waveforms and synthesis types.

• Waveforms: The four main types are:
• Sine waves (smooth, pure tones).
• Sawtooth waves (bright, full, and harmonically rich).
• Square waves (hollow, buzzy).
• Triangle waves (softer, similar to sine waves but with more harmonics).
• Synthesis Types:
• Subtractive synthesis (removing parts of the sound using filters).
• Additive synthesis (building up sound by adding harmonics).
• FM synthesis (using frequency modulation for complex tones).
• Wavetable synthesis (using pre-recorded waveforms for unique textures).

Most popular synthesizers use subtractive synthesis, but exploring each type will help you understand how to approach sound design.

2. Choose Your Starting Point: Oscillators

The oscillator is the heart of your synth sound. Think of it as the generator of your tone.

• Waveform Selection: Choose a waveform that aligns with the type of sound you’re aiming for:
• Bass sounds might start with a sawtooth or square wave.
• Leads often use sawtooth waves for their sharp edge.
• Pads tend to benefit from complex wavetables or smooth sine and triangle waves.
• Detuning and Blending: Some synths allow you to layer multiple oscillators and detune them slightly. This creates a fuller, richer sound. Experiment with subtle detuning between oscillators to add thickness and warmth to your sound.

3. Shape Your Sound with Filters

Filters are key in defining the character of your sound by removing or accentuating certain frequencies. Common filter types include:

• Low-pass filter (LPF): Allows low frequencies to pass through and reduces higher ones, great for mellow sounds or bass.
• High-pass filter (HPF): Allows high frequencies to pass through, useful for thinner or sharper textures.
• Band-pass filter (BPF): Only lets a specific range of frequencies through, ideal for unique or “nasal” sounds.

Experiment with the filter’s cutoff (frequency threshold) and resonance (frequency boost around the cutoff) to give your sound depth and character. Higher resonance values can create more intense, cutting sounds.

4. Add Movement with Envelopes

Envelopes control the evolution of a sound over time, typically affecting volume, filter, or pitch. The most common type is the ADSR envelope:

• Attack: How long it takes for the sound to reach full volume after a key is pressed.
• Decay: The time it takes to fall to the sustain level.
• Sustain: The level held while the key is pressed.
• Release: The time it takes for the sound to fade out after the key is released.

For example:

• Pads and sustained sounds: Use a longer attack and release for smooth fades.
• Plucky or percussive sounds: Use short attack and decay times with little to no sustain.

5. Create Texture with LFOs (Low-Frequency Oscillators)

LFOs allow you to modulate parameters like pitch, filter cutoff, or amplitude over time, adding texture and movement.

• Assign an LFO to pitch for vibrato.
• Assign an LFO to the filter cutoff for a wah-wah effect.
• Adjust the rate and intensity to control how subtle or pronounced the movement is. For instance, a slow LFO on the amplitude can create a gentle pulsing effect, perfect for ambient sounds.

Experimenting with LFO rates and depths helps create everything from subtle changes to dramatic transformations in your sound.

6. Add Effects for Polish and Dimension

Effects can take a sound from raw to refined, giving it polish and dimension. Popular synth effects include:

• Reverb: Adds space and depth, especially useful for pads and ambient sounds.
• Delay: Creates echoes that add rhythm and depth to leads or arpeggios.
• Chorus: Thickens the sound by creating slight variations, useful for a fuller tone.
• Distortion: Adds warmth, crunch, or grit, great for aggressive basses or leads.

Each effect allows for further customization; subtle tweaks can create entirely new sounds.

7. Experiment with Modulation Matrix or Routing

Some synths allow for advanced routing through a modulation matrix, where you can assign sources (like LFOs or envelopes) to multiple destinations (like pitch, filter cutoff, or even effect parameters).

Experiment with unusual combinations:

• Pitch modulation by an envelope for pitch slides.
• Filter cutoff modulation by key tracking, where the cutoff changes depending on the note played.
• Velocity sensitivity for dynamics based on how hard you play.

A modulation matrix provides nearly limitless options, letting you add personal touches to each sound.

8. Fine-Tuning and Final Adjustments

At this stage, listen closely to how your sound fits within the context of your project. Adjust levels, test for clipping, and listen with fresh ears or on different playback systems.

• Layering: You can layer multiple sounds to make complex textures or unique hybrids.
• Automation: Use automation to add real-time changes in the sound within your track, keeping it dynamic and engaging.

Wrapping Up

Designing synth sounds from scratch is both an art and a science. It takes patience and practice, but as you gain familiarity with the components of synthesis, you’ll develop a style and workflow that feels natural. The key is experimentation—there’s no wrong answer, only new possibilities to explore.

Happy sound designing!