---
id: "2026-01-28-ace-step-1-5"
url: "https://postcutoff.com/e/2026-01-28-ace-step-1-5/"
as_of: "2026-11-13T13:49:00+01:00"
date: "2026-01-28"
date_precision: day
category: open-source
importance: 3
confidence: medium
status: [Partly confirmed]
sources: 4
editor: human editor
human_review: null
version: "2026-10-04"
---

As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/2026-01-28-ace-step-1-5/

# ACE-Step 1.5: MIT-licensed song generator that runs on consumer GPUs

ACE Studio and StepFun released ACE-Step 1.5, an MIT-licensed text-to-music model (LM planner + Diffusion Transformer) that generates full songs with lyrics in 50+ languages in seconds on consumer hardware, with covers, repainting and LoRA fine-tuning; a 4B-DiT XL series followed on 2026-04-02.

## Key facts
- Songs from 10 s to 10 min; under 2 s per song on an A100, under 10 s on an RTX 3090
- Runs in under 4 GB VRAM with offload (XL needs >=12 GB)
- LoRA personalization from about 8 songs in ~1 hour on a 12 GB GPU
- License: MIT; weights on Hugging Face (ACE-Step/Ace-Step1.5)
- ACE-Step 1.5 XL (4B DiT; base/sft/turbo) released 2026-04-02

## What happened

The successor to 2025's ACE-Step v1 (3.5B) splits generation into a language-model "planner" that writes a full song blueprint and a Diffusion Transformer that renders audio, aligned with reinforcement learning that needs no external reward model. It ships with cover generation, repainting, vocal-to-backing-track conversion, stem separation and LoRA training, and supports Mac, AMD, Intel and CUDA.

The exact launch day (2026-01-28) comes from secondary coverage; Hugging Face repos were created on 2026-01-23 and the tech report was submitted on 2026-01-31.

## Why it matters

It made near-commercial song generation practical on laptops and gaming GPUs under a permissive license, the open alternative to Suno/Udio in the year the commercial services moved to licensed data. The authors claim quality above most commercial models (not independently verified).

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): in its training data
- Claude Opus 5.5 (training cutoff June 2026): in its training data
- Gemini 4 Hydrogen (training cutoff March 2026): in its training data
- Grok 4.7 (training cutoff May 2026): in its training data

## Sources

1. [GitHub: ace-step/ACE-Step-1.5](https://github.com/ace-step/ACE-Step-1.5) (github.com, code)
2. [Tech report: ACE-Step 1.5 (arXiv 2602.00744)](https://arxiv.org/abs/2602.00744) (arxiv.org, paper)
3. [Hugging Face: ACE-Step/Ace-Step1.5](https://huggingface.co/ACE-Step/Ace-Step1.5) (huggingface.co, code)
4. [Project page](https://ace-step.github.io/ace-step-v1.5.github.io/) (ace-step.github.io, official)

## Changes

- 2026-09-29 (filed): Created

## Related

- 2026-08-13: [MiniMax open-sources Music 3.0, a five-minute full-song generator](https://postcutoff.com/e/2026-08-13-minimax-music-3-open-weights/index.md)
- Models: [ACE-Step 1.5 (incl. 1.5 XL)](https://postcutoff.com/m/ace-step-1-5/) (`ace-step-1-5`)