Sound Effects Generation

A generated sound that seems right may still fail on transients, tails and mono

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Sample RateTimbre

The problem

A generated sound effect can seem right and still be unusable. It thins out in mono, its tail covers the next line, the attack is soft, and a layer of generation noise sits underneath. Drop it into a game or a cut, put dialogue over it, and the mix turns to mud.

How it works

Usability comes down to three things, how clear the transient is, how controllable the tail is, and whether the spectrum leaves room for anything else. Recorded foley has a real room and a real action, so its attack carries a definite point of contact. A generated effect is a statistical average, with a soft attack, built-in reverb, and phase problems that show up when folded to mono. Low and high end often exceed what is needed and take space from other elements.

Practice

Sort by type first. Footsteps, cloth, doors and machinery have a clear action, so record them; a few dozen files last a long time. Explosions, magic and science fiction have no real counterpart and can be generated, but they work better as layers than as the main event. Check every generated file for mono compatibility, tail length, DC offset and peak. When it has to sit on picture, cut the generated reverb and add your own room. Before batch delivery, run QC on naming, sample rate, level and silence at the head, and listen to the first and last three seconds of each file. Three takes of one action sound more like one world than ten generated variants.

What to listen for

In funk-groove1, how hard the drum transient is, which is the part generation struggles to keep. In Telemann's concerto for three trumpets and timpani, the attack and decay of the rolls; in Blitzstein's Percussion Music, where noise-based material sits in the spectrum; in Grieg's Bell Ringing, the overtone structure of a bell. Against a generated version, the difference is usually in the first few milliseconds.

Sources

• 音效与拟音的可用性标准，依后期制作通识核对，未抄原文
• Usability criteria for sound effects and foley, checked against general post-production practice, not copied

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