Bells are pure resonance, which makes them forgiving to generate and easy to get subtly wrong. Most of a bell's identity is in its decay: how long it rings, how the partials beat against each other as it fades, and whether the room joins in. With the decay right, even a rough render is convincing. With it wrong, extra brightness does not help.
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.
single large church bell tolling, deep bronze strike with a long beating decay, stone tower and open air
full peal of church bells ringing changes, overlapping bronze tones in a village, open air, distant
hotel reception desk bell struck once, bright short ding with a clean metallic decay, lobby reverb
bicycle bell thumbed twice, bright thin metallic trill, close mic, outdoor street
metal wind chimes moving in a light breeze, random overlapping tuned tones, outdoor porch, seamless loop
boxing ring bell struck three times to end a round, harsh bright clang, arena reverb with crowd behind
brass hand bell shaken vigorously, rapid clapper strikes with a bright ringing wash, close mic
ship's bell struck twice on deck, bright brass ring with sea and wind behind, open outdoor
Tibetan singing bowl struck once and left to ring, pure sustained tone with slow beating partials, quiet room
orchestral tubular bell struck with a mallet, bright metallic strike with a very long shimmering decay, concert hall
These models respond to physical description. Name the material, the action and the space.
single large church bell tolling, deep bronze strike with a long beating decay, stone tower and open air
"Beating decay" names the slow interference between partials that only large bells produce. It is the strongest size cue available.
hotel reception desk bell struck once, bright short ding with a clean metallic decay, lobby reverb
"Short" and "clean" do the same job for a small bell: no beating, no wobble, gone in a second.
full peal of church bells ringing changes, overlapping bronze tones in a village, open air, distant
"Ringing changes" is the term for the pattern English peals use. It produces overlapping, non-repeating tones instead of a chord.
Tibetan singing bowl struck once and left to ring, pure sustained tone with slow beating partials, quiet room
"Left to ring" tells the model not to cut the tail, and the tail carries this sound's character.
A hand bell rings for under a second and a church bell for ten or more, and nothing else in the sound shows scale as clearly. So give the render enough seconds for the tail to finish. A large bell rendered into a three-second clip loses the part that makes it sound large. Every big-bell prompt here asks for ten seconds or more for that reason.
Real bells are not perfectly tuned. Their partials sit slightly apart, and as they decay they interfere and produce a slow wobble in the tail, which campanologists call beating. Synthetic bells lack it and sound sterile. "Beating decay" and "slow beating partials" reliably produce it, and it moves a generation from sampled keyboard toward cast bronze faster than anything else.
Bells are usually heard through their surroundings: a tower, a hall, a village across fields. Distance matters as much as size. The same bell is bright and metallic up close, and at two hundred metres it is a warm low tone with most of the attack gone. If a bell sounds too aggressive, move it instead of filtering it: add "distant" or "heard across fields" and the model handles the air absorption.
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}'