POST /v1/sound-generation HTTP/1.1
Host: api.elevenlabs.io
{
"text": "smooth jazz instrumental track with no vocals",
"model_id": "eleven_multilingual_v2"
// MISSING: "instrumental": true
}
Result: Routed to Voice Model Tier
Cost for 12.8s: 1,591 CREDITS
POST /v1/music/generation HTTP/1.1
Host: api.elevenlabs.io
{
"prompt": "smooth jazz groove in Ab minor",
"duration_seconds": 12.8,
"instrumental": true, // STRICT INJECTION
"model_id": "music_v1"
}
Result: Routed to Instrumental DSP Tier
Cost for 12.8s: 339 CREDITS (78.7% SAVED)
Everyday Analogy: Typing "instrumental, no vocals" into a text prompt without flipping the hidden code switch is like ordering a plain cheese pizza, getting charged for triple lobster toppings, and still finding random pieces of fish on your slice! Click below to hear the "phantom vocal mumbling" that leaks into unflagged tracks.
Production wrapper enforcing instrumental=True before dispatching HTTP requests: