Metal is the most tonal material in a sound library. Struck wood or stone stops quickly; struck metal keeps ringing, and the ring tells you the size of the object for as long as it lasts. That makes metal the raw material for much of horror and most industrial sci-fi. These prompts treat resonance as the main thing you specify.
Every clip shows the exact prompt that produced it. The render script reads its prompts from the same file as this page. Copy one, change a word and generate your own.
large thin metal sheet being flexed and wobbled, deep warbling thunder-like resonance, close mic, dry
steel pipe struck hard with a wrench, bright metallic clang with a long ringing sustain, empty warehouse
heavy iron chain dragged slowly across a concrete floor, dense clinking links, basement reverb
ship hull groaning under pressure, low metallic strain with creaking rivets, enormous enclosed space
rusted metal scraping against rusted metal, harsh grinding rasp with a squealing high edge, close mic
blacksmith hammering hot steel on an anvil, rhythmic bright strikes with a ringing tail, stone forge
aluminium can crushed in a fist, thin buckling metal with a crinkling collapse, very close mic, dry
steel girder dropped onto concrete, enormous low clang with a slow decaying wobble, construction site
taut steel wire plucked hard, sharp descending twang with a long metallic decay, close and dry
corrugated metal shop shutter rolled down fast and slamming, rattling ribs with a hard final clang, street
These models respond to physical description. Name the material, the action and the space.
large thin metal sheet being flexed and wobbled, deep warbling thunder-like resonance, close mic, dry
Thin metal bends instead of ringing. "Warbling" gets you the bend; without it you get a clang.
steel pipe struck hard with a wrench, bright metallic clang with a long ringing sustain, empty warehouse
Naming the striker as well as the object fixes the transient. The room then supplies the sustain.
ship hull groaning under pressure, low metallic strain with creaking rivets, enormous enclosed space
"Under pressure" turns an impact into a groan: it tells the model the force is continuous.
rusted metal scraping against rusted metal, harsh grinding rasp with a squealing high edge, close mic
Saying both surfaces are rusted doubles the texture. A scrape between two named materials is more specific than "metal scrape".
You judge the size of a piece of metal by how long it rings after the hit more than by the attack. A small object rings for a fraction of a second; a girder or a hull rings for many seconds and wobbles as different modes decay at different rates. When a metal sound reads as the wrong size, change the tail and leave the hit alone: ask for "a long ringing sustain" or "dead, no ring", and give the render enough seconds for the tail to fit.
Clean and rusted metal sound different: clean surfaces slide and ring, corroded ones catch, rasp and squeal. "Rusted", "corroded" and "old" are among the few adjectives these models respond to reliably, because they map onto real spectral differences. If a metal scrape comes back too smooth and synthetic, add rust before you rewrite the action.
Many unsettling horror sounds are metal recorded in unusual ways: a sheet flexed slowly, a wire bowed, a hull straining. Metal produces inharmonic partials, which sound tonal without fitting any musical scale, and that makes a sound feel wrong. If you are building dread, generate the source here and pitch it down. You get the same kind of result as the horror collection, with more control over the source.
The models run on your machine, which changes the cost, the privacy and what you can automate.
Weights are fetched once. After that, generation, the library and the API all work with the network off. Everything lives in one SQLite file and one folder of WAVs under ~/.soundbox, and nothing is uploaded.
Soundbox runs an MCP server in the same process, with tools for generating and listing sounds. Generated files come back as absolute paths, so an agent can copy them into a project.
Every model's terms are shown before you download it, and non-commercial weights need an explicit confirmation. Soundbox is MIT. The licence of the model that made a sound governs what you may do with it.
claude mcp add --transport http soundbox http://127.0.0.1:17494/mcpcurl -X POST http://127.0.0.1:17494/api/generate \
-H 'Content-Type: application/json' \
-d '{"model":"audiocpp-stable-audio-3-sfx","prompt":"8-bit coin pickup blip","duration_s":1}'