Sound Design and Synth Fundamentals

This video teaches sound design fundamentals that apply to any synthesizer or software, covering four basic waveforms, additive and subtractive synthesis, filters, ADSR envelopes, LFO, unison, and effects.

• Sine wave: The simplest waveform with one harmonic, smooth sound, useful for bass and sub design • Triangle wave: Slightly buzzy with more harmonics than sine, more harmonically rich • Square wave: Squared-off waveform with many harmonics, very buzzy and rich in the top end • Sawtooth wave: Single slanted side (no pyramids), most harmonically rich and buzzy of all four

Oscilloscope and frequency analyzer to visualize waveforms, Three Times Oscillator (a basic synthesizer with three oscillators), and Serum synthesizer to demonstrate different controls.

Almost all complex synthesized sounds are based on these four basic wave shapes. Spend time identifying what each sounds like when played with single notes and chords to develop familiarity.

Additive synthesis starts with one wave shape and makes it more complicated by layering additional waves on top. For example, adding a sine wave to a square wave rounds off the tops, or combining a sine with a sawtooth creates a buzzy hybrid sound.

The opposite approach: start with a complex waveform and take away from it to create new sounds. Using EQ and filters to remove frequencies from a sawtooth wave reduces harshness and changes the overall character.

Instead of using external plugins, many synthesizers have filters and effects built directly into the synth itself, allowing you to modify sounds from within the synthesizer.

Both synthesis methods give you different creative approaches to sound design—building up from simple sources or subtracting from complex ones.

Unison adds more voices to a single note, duplicating the oscillator and panning the copies around the stereo field while slightly detuning them to create a richer, fuller, and more professional sound.

• Detuning extra voices slightly thickens and fullens the sound • Too much detuning can sound bad, so careful balance is needed • Best results often come from 3-7 voices rather than maximum settings • Excessive unison can strain your computer's CPU

Unison can be applied to any basic waveform—sine, sawtooth, triangle, or square—to enhance richness and create more interesting textures.

Experiment with different voice counts rather than defaulting to 16 voices. Some of the best sounds use only 3 voices, and be mindful of CPU impact when adding many voices.

Almost every synthesizer has filters that work similarly to EQ, allowing you to remove frequencies from a sound. A filter requires selecting a type and adjusting a cutoff parameter.

• Low-pass filter: Allows low frequencies through while cutting away high frequencies • High-pass filter: Cuts away the low end and only lets the high end through • Comb and phasing filters: Create special effects with unique sonic characteristics

Moving the cutoff parameter opens or closes the filter, allowing more or fewer frequencies to pass through, dramatically changing the sound character.

Filters are essential tools for shaping the tonal character of any synthesized sound and are one of the most frequently used controls in sound design.

ADSR stands for Attack, Decay, Sustain, and Release. It determines the volume shape and behavior of a sound when keys are pressed and released. Serum adds a Hold parameter for more control.

• Attack: How long it takes the sound to reach maximum volume after a key is pressed • Decay: Time it takes to fall from peak to the sustain level • Sustain: The level the sound holds while a key is being held • Release: How long the sound takes to fade away after releasing a key

Adjusting ADSR envelopes creates the majority of your sound (80-90%). Short attacks and releases can create plucking effects, while longer attacks work for pad sounds.

Many synthesizers allow you to adjust the shape of envelope curves for fine-tuning, enabling both sharp and smooth transitions between attack, decay, sustain, and release stages.

LFO stands for Low Frequency Oscillator and adds movement and automation to any synthesizer parameter. It operates at frequencies between 0-40 Hz that we can hear as modulation rather than as pitch.

• Linking LFO to filter cutoff creates opening and closing filter sweeps • Can be synchronized to BPM or set to specific Hertz values • Eliminates the need to manually create automation clips in your DAW • Can be applied to any synthesizer parameter, not just filters

You can adjust LFO speed, shape, and depth. In Serum, you can create custom shapes rather than using preset curves, enabling sidechaining effects and complex modulation patterns.

Using LFO is much faster than creating automation clips on your playlist and manually assigning control points, making it an essential tool for efficient sound design.

Sound design extends beyond the synthesizer itself. Most DAWs and synthesizers include effects chains where you can add distortion, chorus, EQ, delay, reverb, and other effects to further shape your sound.

• Distortion: Adds aggression and character • Downsampling: Creates digital degradation • Reverb: Adds space and dimension • Chorus: Creates width and movement

Adding effects can dramatically transform a simple sound into something complex and professional. Removing effects reveals how much the synth engine itself contributes versus the effects processing.

Regardless of which synthesizer you use (Serum, Three Times Oscillator, analog-modeled synths), understanding oscillators, ADSR envelopes, filters, LFO, and unison helps you recognize and create the sounds you want in any software.