stepfun-ai/Step-Audio-R1.1
Overview of Step-Audio-R1.1
<a href="https://www.stepfun.com/studio/audio?tab=conversation"><img src="https://img.shields.io/static/v1?label=Space%20Playground&message=Studio&color=yellow"></a> <a href="https://huggingface.co/spaces/stepfun-ai/Step-Audio-R1"><img src="https://img.shields.io/static/v1?label=Space&message=Web&color=green"></a>  
Introduction
Step-Audio R1.1 (Realtime) is a major upgrade to Step-Audio-R1, designed for interactive spoken dialogue with both real-time responsiveness and strong reasoning capability.
Unlike conventional streaming speech models that trade intelligence for latency, R1.1 enables thinking while speaking, achieving high intelligence without sacrificing speed.
Mind-Paced Speaking (Low Latency)
Based on the research *Mind-Paced Speaking*, the Realtime variant adopts a Dual-Brain Architecture:
- A Formulation Brain responsible for high-level reasoning
- An Articulation Brain dedicated to speech generation
This decoupling allows the model to perform Chain-of-Thought reasoning during speech output, maintaining ultra-low latency while handling complex tasks in real time.
Acoustic-Grounded Reasoning (High Intelligence)
To address the inverted scaling issue—where reasoning over transcripts can degrade performance—Step-Audio R1.1 grounds its reasoning directly in acoustic representations rather than text alone.
Through iterative self-distillation, extended deliberation becomes a strength instead of a liability. This enables effective test-time compute scaling and leads to state-of-the-art performance, including top-ranking results on the AA benchmark.



Online demonstration
StepFun Audio Studio
- Both Step-Audio-R1.1 are available in our StepFun Audio Studio.
- You will need an API key from the StepFun Open Platform.
WeChat group
You can scan the following QR code to join our WeChat group for communication and discussion. <div align="center"> <img src="https://cdn-uploads.huggingface.co/production/uploads/66518fd07d8cb2629a514c18/DRdnp1SN-yxhlNOfy26mE.jpeg" width="200" alt="QR code"> </div>
Model Usage
📜 Requirements
- GPU: NVIDIA GPUs with CUDA support (tested on 4×L40S/H100/H800/H20).
- Operating System: Linux.
- Python: >= 3.10.0.
⬇️ Download Model
First, you need to download the Step-Audio-R1 model weights.
Method A · Git LFS
git lfs install
git clone https://huggingface.co/stepfun-ai/Step-Audio-R1.1Method B · Hugging Face CLI
hf download stepfun-ai/Step-Audio-R1.1 --local-dir ./Step-Audio-R1.1🚀 Deployment and Execution
We provide two ways to serve the model: Docker (recommended) or compiling the customized vLLM backend.
🐳 Method 1 · Run with Docker (Recommended)
A customized vLLM image is required.
- Pull the image:
docker pull stepfun2025/vllm:step-audio-2-v20250909- Start the service: Assuming the model is downloaded in the
Step-Audio-R1folder in the current directory.
docker run --rm -ti --gpus all \
-v $(pwd)/Step-Audio-R1.1:/Step-Audio-R1.1 \
-p 9999:9999 \
stepfun2025/vllm:step-audio-2-v20250909 \
-- vllm serve /Step-Audio-R1.1 \
--served-model-name Step-Audio-R1.1 \
--port 9999 \
--max-model-len 16384 \
--max-num-seqs 32 \
--tensor-parallel-size 4 \
--chat-template '{%- macro render_content(content) -%}{%- if content is string -%}{{- content.replace("<audio_patch>\n", "<audio_patch>") -}}{%- elif content is mapping -%}{{- content['"'"'value'"'"'] if '"'"'value'"'"' in content else content['"'"'text'"'"'] -}}{%- elif content is iterable -%}{%- for item in content -%}{%- if item.type == '"'"'text'"'"' -%}{{- item['"'"'value'"'"'] if '"'"'value'"'"' in item else item['"'"'text'"'"'] -}}{%- elif item.type == '"'"'audio'"'"' -%}<audio_patch>{%- endif -%}{%- endfor -%}{%- endif -%}{%- endmacro -%}{%- if tools -%}{{- '"'"'<|BOT|>system\n'"'"' -}}{%- if messages[0]['"'"'role'"'"'] == '"'"'system'"'"' -%}{{- render_content(messages[0]['"'"'content'"'"']) + '"'"'<|EOT|>'"'"' -}}{%- endif -%}{{- '"'"'<|BOT|>tool_json_schemas\n'"'"' + tools|tojson + '"'"'<|EOT|>'"'"' -}}{%- else -%}{%- if messages[0]['"'"'role'"'"'] == '"'"'system'"'"' -%}{{- '"'"'<|BOT|>system\n'"'"' + render_content(messages[0]['"'"'content'"'"']) + '"'"'<|EOT|>'"'"' -}}{%- endif -%}{%- endif -%}{%- for message in messages -%}{%- if message["role"] == "user" -%}{{- '"'"'<|BOT|>human\n'"'"' + render_content(message["content"]) + '"'"'<|EOT|>'"'"' -}}{%- elif message["role"] == "assistant" -%}{{- '"'"'<|BOT|>assistant\n'"'"' + (render_content(message["content"]) if message["content"] else '"'"''"'"') -}}{%- set is_last_assistant = true -%}{%- for m in messages[loop.index:] -%}{%- if m["role"] == "assistant" -%}{%- set is_last_assistant = false -%}{%- endif -%}{%- endfor -%}{%- if not is_last_assistant -%}{{- '"'"'<|EOT|>'"'"' -}}{%- endif -%}{%- elif message["role"] == "function_output" -%}{%- else -%}{%- if not (loop.first and message["role"] == "system") -%}{{- '"'"'<|BOT|>'"'"' + message["role"] + '"'"'\n'"'"' + render_content(message["content"]) + '"'"'<|EOT|>'"'"' -}}{%- endif -%}{%- endif -%}{%- endfor -%}{%- if add_generation_prompt -%}{{- '"'"'<|BOT|>assistant\n<think>\n'"'"' -}}{%- endif -%}' \
--enable-log-requests \
--interleave-mm-strings \
--trust-remote-codeAfter the service starts, it will listen on localhost:9999.
🐳 Method 2 · Run from Source (Compile vLLM)
Step-Audio-R1 requires a customized vLLM backend.
- Download Source Code:
git clone https://github.com/stepfun-ai/vllm.git
cd vllm- Prepare Environment:
python3 -m venv .venv
source .venv/bin/activate- Install and Compile: vLLM contains both C++ and Python code. We mainly modified the Python code, so the C++ part can use the pre-compiled version to speed up the process.
# Use pre-compiled C++ extensions (Recommended)
VLLM_USE_PRECOMPILED=1 pip install -e .- Switch Branch: After compilation, switch to the branch that supports Step-Audio.
git checkout feat/step-audio-support- Start the Service:
# Ensure you are in the vllm directory and the virtual environment is activated
source .venv/bin/activate
python3 -m vllm.entrypoints.openai.api_server \
--model ../Step-Audio-R1.1 \
--served-model-name Step-Audio-R1.1 \
--port 9999 \
--host 0.0.0.0 \
--max-model-len 65536 \
--max-num-seqs 128 \
--tensor-parallel-size 4 \
--gpu-memory-utilization 0.85 \
--trust-remote-code \
--enable-log-requests \
--interleave-mm-strings \
--chat-template '{%- macro render_content(content) -%}{%- if content is string -%}{{- content.replace("<audio_patch>\n", "<audio_patch>") -}}{%- elif content is mapping -%}{{- content['"'"'value'"'"'] if '"'"'value'"'"' in content else content['"'"'text'"'"'] -}}{%- elif content is iterable -%}{%- for item in content -%}{%- if item.type == '"'"'text'"'"' -%}{{- item['"'"'value'"'"'] if '"'"'value'"'"' in item else item['"'"'text'"'"'] -}}{%- elif item.type == '"'"'audio'"'"' -%}<audio_patch>{%- endif -%}{%- endfor -%}{%- endif -%}{%- endmacro -%}{%- if tools -%}{{- '"'"'<|BOT|>system\n'"'"' -}}{%- if messages[0]['"'"'role'"'"'] == '"'"'system'"'"' -%}{{- render_content(messages[0]['"'"'content'"'"']) + '"'"'<|EOT|>'"'"' -}}{%- endif -%}{{- '"'"'<|BOT|>tool_json_schemas\n'"'"' + tools|tojson + '"'"'<|EOT|>'"'"' -}}{%- else -%}{%- if messages[0]['"'"'role'"'"'] == '"'"'system'"'"' -%}{{- '"'"'<|BOT|>system\n'"'"' + render_content(messages[0]['"'"'content'"'"']) + '"'"'<|EOT|>'"'"' -}}{%- endif -%}{%- endif -%}{%- for message in messages -%}{%- if message["role"] == "user" -%}{{- '"'"'<|BOT|>human\n'"'"' + render_content(message["content"]) + '"'"'<|EOT|>'"'"' -}}{%- elif message["role"] == "assistant" -%}{{- '"'"'<|BOT|>assistant\n'"'"' + (render_content(message["content"]) if message["content"] else '"'"''"'"') -}}{%- set is_last_assistant = true -%}{%- for m in messages[loop.index:] -%}{%- if m["role"] == "assistant" -%}{%- set is_last_assistant = false -%}{%- endif -%}{%- endfor -%}{%- if not is_last_assistant -%}{{- '"'"'<|EOT|>'"'"' -}}{%- endif -%}{%- elif message["role"] == "function_output" -%}{%- else -%}{%- if not (loop.first and message["role"] == "system") -%}{{- '"'"'<|BOT|>'"'"' + message["role"] + '"'"'\n'"'"' + render_content(message["content"]) + '"'"'<|EOT|>'"'"' -}}{%- endif -%}{%- endif -%}{%- endfor -%}{%- if add_generation_prompt -%}{{- '"'"'<|BOT|>assistant\n<think>\n'"'"' -}}{%- endif -%}'After the service starts, it will listen on localhost:9999.
