Granular Sampling

Chop a sample into millisecond grains and reassemble them to stretch, freeze or cloud the sound.

Related

SamplerSample RateTimbre

The problem

Stretching a recording tenfold without changing pitch, or freezing a chord into a cloud that never fades, is beyond ordinary time stretching, which either fails or leaves a metallic residue. Granular sampling takes another route: instead of processing the whole waveform, it cuts the sound into countless short grains and rearranges them in new time and pitch.

How it works

Each grain lasts from a few milliseconds to over a hundred, shaped by a window so the cuts do not click. Grains overlap, and more overlap means smoother while less means grainier. The read position can scan, randomise or freeze, and scan speed decides whether the result stretches or compresses. Grain length shapes timbre: too short loses low end, too long reveals fragments of the original pitch. Overlapping grains are not phase-aligned, so comb filtering and random interference appear.

Settings and practice

Choose grain length first and try short before long. Overlap sets smoothness: high for clouds, low for rhythmic texture. Zero scan speed freezes; slow forward scanning stretches. Add random offset to break up the metallic edge, but not so much that pitch dissolves. Shape with filters and envelopes rather than expecting grains to supply clear bass. The result suits beds, transitions and effects more than lead melodies.

What to listen for

In the piano tail, how the decay stretches into a sustained tone; in the organ, the drift of the cloud; in the drum loop, how transients scatter into texture. Granular sound sits between instrument and noise, and what you listen for is texture rather than pitch.

Sources

• 粒子合成的窗函数与重叠原理，依声音设计公开资料核对，未抄原文
• 颗粒长度与音色变化的关系，依数字音频通识核对，未抄文本

Used for fact-checking only; all prose is original.