Qwen-Audio is an end-to-end real-time voice interaction model for low-latency voice conversations. Use cases include voice assistants, intelligent customer service, and AI companions.
Overview
Qwen-Audio converts real-time audio to speech and text over a full-duplex connection, with streaming input and streaming output.
In addition to WebSocket, this model also supports the AOQ and WebRTC protocols. For client-side integration that prioritizes stable latency, resilience on weak networks, and built-in full-duplex noise suppression and echo cancellation, AOQ is recommended. For a protocol comparison, see Realtime API overview.
- Three interaction modes: acoustic VAD (server_vad), intelligent semantic turn detection (smart_turn), and manual control (push-to-talk)
- In smart_turn mode, the model combines acoustic perception and semantic understanding to determine turn boundaries, so filler sounds such as "uh" or "hmm" don't interrupt the conversation
- Function Calling support lets the model decide when to invoke external tools for additional information
- Conversation context management: create, retrieve, and delete conversation items to inject historical context or remove irrelevant items
- Expressive voice output that dynamically adjusts tone, pacing, and emotion based on the conversation context
- Support for system voices and cloned voices; use Voice Cloning to create a custom AI voice for speech output
- Speaker enhancement in smart_turn mode: pass pre-recorded audio from a target user so the model can lock onto that speaker during duplex conversations, effectively blocking other voices and background noise
How it works
Qwen-Audio uses a full-duplex connection with an event-driven architecture. The client and server exchange data simultaneously over a persistent connection: the client continuously streams microphone audio while the server returns speech and text responses in real time. The entire interaction is event-driven: the client sends events such as session.update and input_audio_buffer.append, and the server responds with events such as response.audio.delta and response.done. No polling is required.
A typical connection lifecycle is: establish WebSocket connection, send session.update to configure session parameters, stream audio and receive responses, then close the connection.
Audio format
| Direction | Format | Specification |
|---|---|---|
| Input (client to server) | PCM | 16 kHz sample rate, 16-bit depth, mono |
| Output (server to client) | PCM | 24 kHz sample rate, 16-bit depth, mono |
Context capacity
The model maintains conversation history. When the number of turns or cumulative audio duration exceeds the following limits, earlier history is automatically discarded. The maximum duration is the upper limit of cumulative audio the model's context can retain.
| Model | Max audio turns | Max audio duration |
|---|---|---|
| qwen-audio-3.0-realtime-plus | 50 | 300 seconds |
| qwen-audio-3.0-realtime-flash | 50 | 300 seconds |
Prerequisites
- Obtain an API key and configure it as an environment variable.
- To use the AOQ protocol, download and integrate the AOQ client SDK. For details, see SDK overview.
Quick start
Follow these steps to start a real-time voice conversation with the Qwen-Audio model.
For the WebSocket event interaction sequence of each mode, see Event interaction flow.
server_vad mode. Before running, install the required dependencies:
- macOS
- Debian/Ubuntu
- Windows
realtime_quickstart.py:
python realtime_quickstart.py and speak into the microphone to have a real-time conversation with the model. The server automatically detects the start and end of speech and triggers responses.
Complete example
The following complete example builds on the basic conversation flow above, adding interruption handling and echo suppression. Create the following two files in the same directory:
B64PCMPlayer.py
B64PCMPlayer.py
realtime_demo.py
realtime_demo.py
If your
websockets version is lower than 11, change additional_headers in the code to extra_headers, or upgrade: pip install --upgrade websockets.python realtime_demo.py and speak into the microphone to have a real-time conversation with the model. The system automatically detects the start and end of speech and triggers responses.
The example above uses server_vad mode (server-side acoustic VAD automatically detects the start and end of speech). To use smart_turn (intelligent semantic turn detection) or push-to-talk (manual control) mode, see Interaction modes.
Session configuration
Interaction modes
Qwen-Audio supports three interaction modes: server_vad (acoustic VAD automatically detects the start and end of speech), smart_turn (intelligent semantic turn detection, combining acoustic and semantic signals), and push-to-talk (client manually controls the session). For details on each mode and the event interaction timeline (including sequence diagrams), see Interaction modes.
turn_detection can only be changed before the first audio is sent (IDLE state). Switching interaction modes after the session has started requires reconnecting.turn_detection field in the session.update event:
- server_vad:
- smart_turn:
- push-to-talk:
manual_realtime.py
manual_realtime.py
System instructions
Use the instructions parameter to set the model's role identity, response style, and behavior preferences. Configure this parameter in session.update; it applies to the entire session.
- Define a clear role identity (for example, "You are an intelligent voice assistant" or "You are an English conversation tutor"), and optionally include details such as name or gender.
- Specify a conversational tone and phrasing style, while emphasizing that a natural tone does not compromise content completeness — details, numbers, and specific recommendations must still be included, just expressed in a relaxed, natural way.
- Instruct the model to account for all context constraints in the conversation (such as budget, preferences, restrictions, or prior agreements). When multiple conditions apply, address each one and omit no critical information.
- Control output format: unless the user requests otherwise, avoid emoji and other special characters and Markdown formatting. Output plain text to ensure natural TTS playback.
- Define response strategy: keep simple greetings and casual exchanges brief and natural; for reasoning, multi-condition problems, recommendation lists, or safety advice, prioritize completeness — ensure key information (such as prices, locations, and conditions) is fully present, with no unnecessary preamble, repetition, or filler.
- Set a follow-up strategy: follow the principle of "answer the user's current question first, then naturally pose a follow-up at the end to advance the conversation." Ask only one question at a time; do not ask multiple questions in a row or repeatedly confirm.
instructions configuration for general voice conversation scenarios. It covers role definition, conversational style, format control, and follow-up strategy. Use it directly or adapt it to your needs:
instructions examples cover a range of persona styles. Choose one that fits your use case or customize it further:
- Daisy (Sweet & Cool Companion):
- Len (Cool & Sharp-Tongued):
- Mochen (Calm & Charismatic):
- Hannibal (Elegant & Incisive):
- Heizi (Northeastern Buddy):
Voice configuration
Use the voice parameter to set the TTS voice for model responses. The default is longanqian. Two types of voices are supported.
The voice can only be set in the first
session.update. The field is ignored in subsequent session.update calls.longanqian, longanlingxin, longanlingxi, longanxiaoxin, longanlufeng.
target_model to qwen-audio-3.0-realtime-plus or qwen-audio-3.0-realtime-flash), then pass the returned voice_id as the voice value.
Output modalities
Use the modalities parameter to control the model's output types:
["audio", "text"](default): outputs both speech and text.["text"]: outputs text only, without speech. Suitable for debugging, logging, or scenarios that only need text responses.
response.modalities field in response.create to override the modality setting for a single response.
VAD configuration
In server_vad mode, configure the following parameters in the session.turn_detection object to adjust VAD behavior (these parameters have no effect in smart_turn mode):
| Parameter | Type | Description |
|---|---|---|
threshold | float | VAD sensitivity. Lower values increase VAD sensitivity, making it easier to detect faint sounds (including background noise) as speech. Higher values decrease sensitivity, requiring clearer and louder speech to trigger detection. Range: [-1.0, 1.0]. Default: 0.5. |
silence_duration_ms | integer | Minimum silence duration (in milliseconds) after speech ends before triggering a model response. Lower values produce faster responses but may cause false triggers during brief pauses. Range: [200, 6000]. Default: 800. Recommended range for conversations: 400-800. |
History turn control
Use the max_history_turns parameter to control how many historical QA turns the model references during inference. Higher values let the model review more conversation history for better context understanding, but increase token consumption and inference latency.
max_history_turns: 1-50. Default: 20.
Tuning tips:
- Short conversations (such as quick Q&A): set a lower value (for example, 5-10) to reduce latency.
- Long conversations (such as multi-turn customer service): set a higher value (for example, 30-50) to help the model understand the full context.
Advanced features
Function Calling
Qwen-Audio supports Function Calling, which lets the model decide when to invoke external tools based on the conversation context.
1. Register tools
Configure tools through session.update:
response.function_call_arguments.done, run the tool on the client and send the result back via conversation.item.create:
response.create to have the model generate a response based on the tool result:
A single response can contain multiple
function_call items, and may include both regular messages and function calls. Function call content isn't sent to TTS for playback.realtime_demo.py from the quick start. Make sure B64PCMPlayer.py is in the same directory before running.
realtime_fc_demo.py
realtime_fc_demo.py
python realtime_fc_demo.py and speak into your microphone to try real-time conversations with Function Calling. For example, ask "What's the weather in Hangzhou?" or "How much is a train ticket from Beijing to Shanghai?" and the model automatically invokes the corresponding tool and responds with the result.
Conversation context management
Qwen-Audio lets you manage conversation items in the context through client events. Use this to inject historical context, add text information, or remove irrelevant conversation items.
-
Create a conversation item (
conversation.item.create): inserts a conversation item into the context. The following threeitem.typevalues are supported:message: a regular conversation message. Specifyrole(system,user, orassistant) and acontentarray. Use this to inject conversation history or system instructions.function_call: a function call request. Specifycall_id,name, andarguments(JSON string). Typically generated by the server, but the client can also use this to inject historical function call records.function_call_output: a tool execution result. Specifycall_idandoutput(JSON string). After receiving afunction_call, run the tool on the client and return the result with this type.
previous_item_idparameter specifies the existing conversation item after which to insert the new item. This lets you insert content at any position in the conversation history. If omitted, the new item is appended to the end.- Insert a user message at a specific position:
- Return a Function Calling result:
If the
item.id specified in conversation.item.create already exists in the conversation, an error is returned.- Retrieve a conversation item (
conversation.item.retrieve): queries a conversation item stored on the server. For audio-type content, only the transcription text is returned, not the raw audio data.
- Delete a conversation item (
conversation.item.delete): removes a specific item from the conversation context.
Ambient audio transcription
smart_turn mode only. When VAD detects speech activity but semantic analysis determines it isn't a valid turn (such as noise or filler sounds like "uh" or "hmm"), the server doesn't trigger a conversation turn. Instead, it sends the ASR result to the client as an ambient_audio_transcription event. This transcription isn't written to the conversation context.
delta and completed phases. Use this event to implement ambient audio monitoring or conversation scene awareness.
Speaker enhancement
smart_turn mode only. Pass pre-recorded audio URLs from the target user in session.update. The model will lock onto that speaker during duplex conversations, effectively ignoring other voices and background noise, enabling fluid duplex interactions in open environments.
Configuration: pass publicly accessible voiceprint audio URLs in turn_detection.voiceprint_audio_urls within the first session.update.
- Up to 5 URLs. Audio must be 16 kHz PCM or WAV format.
- This parameter only takes effect in the first
session.update. The field is ignored in subsequent calls.
voiceprint_audio_list.in_progress: registration has started. Sent beforesession.updated, carryingitem_id.voiceprint_audio_list.completed: registration succeeded. Theitem_idmatches the one inin_progress.voiceprint_audio_list.failed: registration failed, with areasonfield describing the error (for example, audio URL is not accessible). A registration failure does not block the ongoing conversation.
Going live
Set up fault tolerance
- Client reconnection: implement automatic reconnection to handle network jitter. Set a reconnection signal in the
on_errorcallback and use exponential backoff (for example, wait 1s, 2s, 4s) for retries. - Error classification: client errors (
invalid_request_error) don't disconnect the session; log them or adjust parameters. Server errors (server_error) terminate the connection and require reconnection. - Interruption handling: in server_vad / smart_turn modes, new user speech automatically interrupts the model's ongoing response (
response.donereturnsstatus=cancelled). Wheninput_audio_buffer.speech_startedis received, immediately clear the local playback buffer to avoid audio overlap.
Connection lifecycle
A typical WebSocket session follows this lifecycle:
- Connect: the client initiates a WebSocket connection and the server returns a
session.createdevent. - Configure: the client sends
session.updateto set the interaction mode, voice, tools, and other parameters. Complete this step before sending any audio. - Interact: the client continuously streams audio (
input_audio_buffer.append). The server performs inference based on VAD detection or manual triggers and returns speech and text in a streaming fashion. - Close: the client closes the WebSocket connection. The server may also disconnect if the connection is idle for too long.
Latency optimization
- Audio chunk size: send about 100 ms of audio data per chunk (16 kHz x 16 bit x mono = 3,200 bytes per chunk). This balances real-time performance with network efficiency.
- Streaming playback: start playing audio as soon as
response.audio.deltaarrives. Don't wait forresponse.doneto play the full response. - Clear buffer on interruption: when
input_audio_buffer.speech_startedis received, immediately clear the local playback buffer to prevent stale audio from continuing to play.
Supported models
Use a Singapore region API key when calling the following models:
- qwen-audio-3.0-realtime-plus
- qwen-audio-3.0-realtime-flash
API reference
- WebSocket API
- Client events
- Server events
- AOQ Client SDK
- Realtime API overview (WebRTC protocol description)