---
id: "2026-09-15-stepfun-stepaudio-3"
url: "https://postcutoff.com/e/2026-09-15-stepfun-stepaudio-3/"
as_of: "2026-11-13T13:49:00+01:00"
date: "2026-09-15"
date_precision: day
category: model-release
importance: 3
confidence: high
status: [Confirmed]
sources: 7
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/2026-09-15-stepfun-stepaudio-3/

# StepFun releases StepAudio 3 family

Full title: StepFun releases StepAudio 3 family; its Realtime model tops Artificial Analysis full-duplex rankings

Chinese lab StepFun launched StepAudio 3, five audio models (Realtime, ASR Max, TTS, Gen, Music). StepAudio 3 Realtime, a "think-while-speaking" full-duplex voice model, ranked #1 on Artificial Analysis for Conversational Dynamics (98.9%) and Speech Reasoning (99.7%), and StepAudio 3 ASR ranked #1 on AA-WER (1.7%).

## Key facts
- API ids: stepaudio-3-realtime-preview, stepaudio-3-chat-preview, stepaudio-3-asr-max, stepaudio-3-tts, stepaudio-3-gen-preview, stepaudio-3-music-preview
- Realtime/Gen/Music free during preview; ASR Max $0.40/hour; TTS $0.36 per 10k characters
- Realtime runs private reasoning in parallel with speech (Think-While-Speaking); 98.9 on Artificial Analysis Full-Duplex Bench
- StepAudio 3 ASR 1.7% WER on AA-WER (StepAudio 2.5 ASR: 4.7%) per Artificial Analysis
- Follows StepAudio 2.5 Realtime (2026-05-26): persona/role-play realtime model (zh/en) with million-scale persona augmentation and role-play RLHF; project page reports 80.41 human eval, 86.36 general dialogue, 79.80 spoken QA, 82.18 paralinguistics, first on all five of StepFun's own dimensions

## What happened

StepFun released a full audio stack at once and made the Realtime, Gen and Music models free during a preview period.
The Realtime model's technical report describes a listen-converse-think-act loop with "Deep Perception", "Seamless Duplex"
and "Think-While-Speaking" components.

## Why it matters

A Chinese startup's voice model led a major independent leaderboard on conversational dynamics ahead of Western
frontier-lab voice models (GPT-Live-1 per StepFun's comparison), showing how fast full-duplex voice is commoditizing.

Leaderboard positions are as of launch and come from StepFun's and Artificial Analysis's X posts.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): 138 days after its cutoff
- Claude Opus 5.5 (training cutoff June 2026): 77 days after its cutoff
- Gemini 4 Hydrogen (training cutoff March 2026): 168 days after its cutoff
- Grok 4.7 (training cutoff May 2026): 107 days after its cutoff

## Sources

1. [StepFun on X - Introducing StepAudio 3](https://x.com/StepFun_ai/status/2099916376274313630) (x.com, official)
2. [StepFun audio models docs](https://platform.stepfun.ai/docs/en/guides/models/audio) (platform.stepfun.ai, docs)
3. [StepFun pricing](https://platform.stepfun.ai/docs/en/pricing/details) (platform.stepfun.ai, docs)
4. [StepAudio 3 Realtime Technical Report](https://arxiv.org/abs/2609.14005) (arxiv.org, paper)
5. [StepAudio 2.5 Realtime project page](https://stepaudiollm.github.io/step-audio-2.5-realtime/) (stepaudiollm.github.io, official)
6. [Decrypt - StepFun's voice AI topped every benchmark (StepAudio 2.5)](https://decrypt.co/369013/stepfun-stepaudio-voice-ai-tops-benchmarks) (decrypt.co, press)
7. [Artificial Analysis on X - StepAudio 3 ASR #1 on AA-WER](https://x.com/ArtificialAnlys/status/2102485740248842710) (x.com, discussion)

## Changes

- 2026-09-29: Added StepAudio 2.5 Realtime project page and its self-reported scores
- 2026-09-29 (filed): Created

## Related

- 2026-09-23: [Alibaba launches Qwen-Audio-3.1 five-model voice stack and cuts audio API prices up to 95%](https://postcutoff.com/e/2026-09-23-qwen-audio-3-1/index.md)
- Models: [StepAudio 3 ASR Max / StepAudio 3 TTS](https://postcutoff.com/m/stepaudio-3-asr-tts/) (`stepaudio-3-asr-tts`), [StepAudio 3 Realtime](https://postcutoff.com/m/stepaudio-3-realtime/) (`stepaudio-3-realtime`)