Model reference · open weights

acestep

Available as managed deployment Audio ACE-Step Music / audio 1 variants 2k dl/mo

acestep is an open-weight audio or speech model from ACE-Step. AxForge deploys and operates it for you on dedicated EU-owned hardware — with the licence handled where one is required.

Available as managed deployment — configured and operated for you on dedicated EU hardware, quoted per deployment.

What it is

MakerACE-Step
TypeAudio & music
TaskMusic / audio
Parameters (lead)2.4B
Runs withtransformers
Released2026-01-23
Popularity2k downloads / month
LicenceOpen weights

About

What acestep is

Model Details

🚀 ACE-Step v1.5 is a highly efficient open-source music foundation model designed to bring commercial-grade music generation to consumer hardware.

Key Features

  • 💰 Commercial-Ready: Unlike many models trained on ambiguous datasets, ACE-Step v1.5 is designed for creators. You can strictly use the generated music for commercial purposes.
  • 📚 Safe & Robust Training Data: The model is trained on a massive, legally compliant dataset consisting of:
    • Licensed Data: Professionally licensed music tracks.
    • Royalty-Free / No-Copyright Data: A vast collection of public domain and royalty-free music.
    • Synthetic Data: High-quality audio generated via advanced MIDI-to-Audio conversion.
  • ⚡ Extreme Speed: Generates a full song in under 2 seconds on an A100 and under 10 seconds on an RTX 3090.
  • 🖥️ Consumer Hardware Friendly: Runs locally with less than 4GB of VRAM.

Technical Capabilities

🌉 At its core lies a novel hybrid architecture where the Language Model (LM) functions as an omni-capable planner: it transforms simple user queries into comprehensive song blueprints—scaling from short loops to 10-minute compositions—while synthesizing metadata, lyrics, and captions via Chain-of-Thought to guide the Diffusion Transformer (DiT). ⚡ Uniquely, this alignment is achieved through intrinsic reinforcement learning relying solely on the model's internal mechanisms, thereby eliminating the biases inherent in external reward models or human preferences. 🎚️

🔮 Beyond standard synthesis, ACE-Step v1.5 unifies precise stylistic control with versatile editing capabilities—such as cover generation, repainting, and vocal-to-BGM conversion—while maintaining strict adherence to prompts across 50+ languages. This paves the way for powerful tools that seamlessly integrate into the creative workflows of music artists, producers, and content creators. 🎸

  • Developed by: [ACE-STEP]
  • Model type: [Text2Music]
  • Language(s): [50+ languages]
  • License: [MIT]

Evaluation

🏗️ Architecture

🦁 Model Zoo

DiT Models

DiT ModelPre-TrainingSFTRLCFGStepRefer audioText2MusicCoverRepaintExtractLegoCompleteQualityDiversityFine-TunabilityHugging Face
acestep-v15-base50MediumHighEasyLink
acestep-v15-sft50HighMediumEasyLink
acestep-v15-turbo8Very HighMediumMediumLink
acestep-v15-turbo-rl8Very HighMediumMediumTo be released

LM Models

LM ModelPretrain fromPre-TrainingSFTRLCoT metasQuery rewriteAudio UnderstandingComposition CapabilityCopy MelodyHugging Face
acestep-5Hz-lm-0.6BQwen3-0.6BMediumMediumWeak
acestep-5Hz-lm-1.7BQwen3-1.7BMediumMediumMedium
acestep-5Hz-lm-4BQwen3-4BStrongStrongStrong

🙏 Acknowledgements

This project is co-led by ACE Studio and StepFun.

📖 Citation

If you find this project useful for your research, please consider citing:

@misc{gong2026acestep,
	title={ACE-Step 1.5: Pushing the Boundaries of Open-Source Music Generation},
	author={Junmin Gong, Yulin Song, Wenxiao Zhao, Sen Wang, Shengyuan Xu, Jing Guo},
	howpublished={\url{https://github.com/ace-step/ACE-Step-1.5}},
	year={2026},
	note={GitHub repository}
}

From the published model card. Full card on the HuggingFace links in the sidebar.

Using it via the API

Call it like any OpenAI endpoint

Once AxForge deploys acestep for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (acestep below is illustrative; you get the exact model name on deployment.)

$ curl -sS https://api.axforge.ai/v1/audio/transcriptions \
  -H "Authorization: Bearer $AXFORGE_API_KEY" \
  -F model="acestep" -F file=@audio.mp3

Create an account — your API key is available in the console. 5M tokens/month currently included with every new account at launch.

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