Suno is instrument-happy — silence makes it nervous, so it fills vocal gaps with piano. A cappella needs aggressive instrument-banning.
1. Triple-ban instruments:
Style: a cappella vocal group, no instruments
Exclude: piano, drums, guitar, bass, any instruments, instrumental backing
Bracket: [A cappella: voices only, absolutely no instruments]
All three layers. One isn't enough.
2. Give the voices jobs: [Bass vocal provides the bassline, vocal percussion keeps rhythm, lead carries melody] — when every voice has a role, there's no empty space for piano to fill.
3. Write the vocal percussion: dm, dm, tss, bap — written beatboxing guides the rhythm section made of mouths.
4. Name the tradition: barbershop quartet, gospel a cappella choir, Pentatonix-style vocal band (style description, not the name in the prompt — describe the sound: 'modern pop vocal band').
5. If a stray instrument survives, stems-mute it. A cappella + stems = surgical instrument removal.
Good luck! Hank founder of SonorixPG