Why Your Synth Keeps Clicking (And How To Fix It) (Patreon)

In this video, I explain why synthesizers and samplers often produce unwanted clicks and crackles, especially when playing notes in a monophonic setup.

The issue usually comes from abrupt changes in the waveform, often caused by starting or stopping a sound away from a zero crossing. I walk through simple ways to avoid this, like adjusting the phase of the oscillator to always begin at zero, adding a short attack or release to your envelope, or using voice alternation techniques.

These solutions can be adapted in most DAWs, not just Bitwig, to achieve smooth, click-free sounds even in monophonic patches.

Clicks and crackles in synthesizers often occur due to abrupt waveform changes, especially when retriggering notes.

The main cause: Oscillator phase does not start at zero (zero-crossing), leading to sharp jumps in the audio signal when keys are pressed.

Free-running oscillators without retrigger cause unpredictable starting points in the waveform, leading to random clicks.

Enabling oscillator retrigger synchronizes phase but can still start at a non-zero value, causing consistent clicks if not set to a zero-crossing.

Offsetting the oscillator phase to start at a zero-crossing (e.g., 25% phase offset on a sine wave) reduces clicks on triggering.

Fast re-triggering of notes can still cause clicks because release phases of the envelope are cut off and replaced by a new attack.

Polyphonic or digi-mono synth modes help by allowing overlapping voices, so the previous note fades out smoothly while the new one starts.

Monophonic synths need delayed retrigger logic to let the release phase finish before triggering a new note, minimizing clicks.

Adding a short attack and/or release time to the amplitude envelope can help reduce clicks but may affect fast note retriggering responsiveness.

Logic delay modules in Bitwig (and similar tools in other DAWs) can delay gate retriggering to ensure envelope release has time to fade out smoothly.

Sample playback (e.g., using a recorder) also benefits from this logic, requiring both the playback and envelope triggers to be properly delayed for smooth fades.

Zero-crossing quantization (triggering only on zero-crossing of the oscillator) is possible but complex and not always practical for all setups.

Alternative envelope shaping using window functions or manipulating phase signals can provide smoother amplitude transitions.

The fundamental solution: Prevent abrupt, steep jumps in the waveform by ensuring smooth fade-ins and fade-outs, especially at note boundaries.