Trailer music is a genre built entirely around a shape: tension, rise, impact. A prompt that only names instruments ('orchestral, choir, big drums') without describing that arc tends to produce something that sounds cinematic in texture but doesn't build anywhere, which is the whole point of a trailer track.
Describe the three-act structure directly
Something like: 'cinematic trailer music, sparse and tense opening with a low string drone, building string ostinato and rising brass through the middle section, full orchestral hit with choir and percussion at the climax.' Naming the sections in order gives the model a timeline to follow, similar to how [Verse]/[Chorus] tags work for song structure.
Vocabulary that actually helps
A handful of trailer-music-specific terms tend to produce more accurate results than generic 'epic' or 'dramatic' descriptions.
- Braams — the low, sustained brass-synth hybrid hit trailers are known for.
- Ostinato — a repeating rhythmic or melodic figure used to build tension.
- Riser/sweep — a rising pitched or noise-based sound leading into an impact.
- Impact/hit — a large percussive downbeat marking a key moment.
- Choir — wordless or Latin-texted vocal layers for scale and gravity.
When you need more length than a standard song
Trailer cues sometimes need to run longer than a typical song, or need to exist as a few connected variations (a 30-second cutdown, a 60-second cue, a 2-minute full version). Standard song length on Autunes runs up to 3 minutes on Free and Pro, and up to 4 minutes on Creator; for anything longer, Long Form is built for exactly this — it generates much longer pieces and automatically splits them into parts.