curl --request POST \
  --url https://proxy.innk.cc/suno/act/vox/{clip_id} \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "vocal_start_s": 18,
  "vocal_end_s": 30
}
'

{
  "id": "507acd16-8b84-4e55-be2b-4329d82efb26"
}