ACE-Step-1.5 — Music Generation AI Model
Describe the music you want — genre, instrumentation, mood, tempo — and get a finished 48 kHz stereo track. Add lyrics and the model sings them; leave them empty and it stays instrumental. The 8-step turbo checkpoint renders a full song in seconds, so a shorts flow can score itself per clip instead of reusing one background bed. Sung vocals follow the chosen language. Default length is 60s; the slider goes to 600s, though the upstream paper only measures quality up to 240s.
What it does
ACE-Step 1.5 takes two text inputs and returns one audio file. The first describes the music - genre, instrumentation, tempo, mood - and the second is optional lyrics, with section tags like [Verse] and [Chorus] to mark structure. Out comes a 48 kHz stereo track.
Length is the part worth pausing on: up to 600 seconds in a single generation, rather than a short loop tiled out to fill the time. Turbo refers to guidance distillation, so eight denoising steps is the default and generating five variations to choose between is reasonable.
When to use it
- Scoring a product video, a demo reel or a course module
- Lyrics that get sung as part of the piece, not spoken over it
- An instrumental, by leaving the lyrics empty - there is no mode to pick
- A full-length track in one pass instead of a loop tiled out
- Sung vocals in English, Korean, Japanese, Chinese or Spanish
Details
- CategoryMusic Generation
- Year2026
- LicenseMIT
Compliance & Provenance
- ProviderACE Studio / StepFun (open weights) · Specialized
- EU AI Act RiskLimited Risk
- Art. 50 TransparencyRequired — AI-generated outputs are marked
Inputs & Outputs
- StyleInputstring
What the music should sound like - genre, instruments, mood, tempo
- LyricsInputstringoptional
Lyrics to sing. Leave empty for an instrumental
- SoundOutputsound
Generated music (48 kHz stereo WAV)
Parameters
- audio_durationfloatdefault 60range 10–600
Track length in seconds.
Track length in seconds (10-600). Upstream only measures quality up to 240s; past that the length works but is unvalidated.
- vocal_languagestringdefault enoptions: en, ko, ja, zh, es
Language the lyrics are sung in (ignored for an instrumental).
Language code for sung vocals. Ignored when lyrics are empty.
- num_inference_stepsintegerdefault 8range 4–50advanced
Diffusion steps. The turbo checkpoint is distilled for 8.
- guidance_scalefloatdefault 7range 1–15advanced
How closely to follow the style prompt.
- seedintegerdefault -1advanced
Random seed. -1 draws a new one each run.
Limitations
- Generated audio is synthetic and has to be marked as such under the EU AI Act
Tags
Alternatives in Audio Models
- Text to Speech (Gemini)
Google Gemini TTS: turn text into a spoken voiceover (Korean/English). Needs API key.