Hip-hop beat for a product ad: instrumental brief and cost

A hip-hop beat for a product ad is cheap to try: one generation on Sume's Music Router is a fixed $0.125, and you can run four different takes for $0.50. Lyria 3.5 is the engine sume/music-auto resolves to today, a mapping the docs say may move without notice. Google's music generation page, read on 2026-10-05, lists an instrumental option, and its safety filters block artist voices and copyrighted lyrics, so brief by sound rather than by name.

The brief

Write tempo, drums, bass, texture and mood, in that order. A usable example: "Instrumental hip-hop beat, 90 BPM, dusty boom-bap drums with a snappy snare, round sub bass, warm electric piano loop, vinyl crackle, confident and relaxed, no vocals, no rapping." Ask for a clean intro of two bars so a voiceover can come in, and an ending that stops on the beat.

Because the music router has no duration field, ask for the length you want in the prompt, such as a 30-second beat, and trim in Timeline if it overshoots.

Putting it under a voiceover

Beats are dense in the low mids, exactly where a voice sits. In a Timeline render, the soundtrack block supports duck_db from 0 to 20. At the default 0 the bed is static; any higher value implements a sidechain duck against the audio spine, so the beat dips when the voice speaks. Try 8 to 12 dB for a spoken ad and lower gain_db (range -60 to 12) if the bass still masks the words. Ducking needs a real audio spine: with audio.mode: "silence" the request is rejected as duck_requires_audio_spine.

• Generation: $0.125 per take.
• Render: $0.10 per output minute, rounded up, so a 30-second ad is $0.10.
• Preflight: POST /v1/timeline-1.0/plan is unbilled.