Cartesia Sonic-3.6 goes GA and tops the Artificial Analysis Speech Arena
Cartesia made Sonic-3.6 generally available on 2026-08-27 (beta 2026-08-17), three months after Sonic-3.5. The state-space-model TTS replies in under 90 ms, supports 44 languages (adding Odia and Urdu) and was preferred over Sonic-3.5 in up to 93% of blind tests. In September it ranked #1 on the Artificial Analysis Speech Arena (~1279 Elo) until ElevenLabs' Eleven v4 took the top spot on 2026-09-28. Cartesia also shipped the Ink-2 streaming STT (2026-07-09) with built-in turn detection.
Key facts
- API id sonic-3.6 (snapshot sonic-3.6-2026-08-27); backwards compatible with sonic-3.5
- <90 ms reply; ~132 chars/s generation (~2x Sonic 3 Conversational); 99.9% uptime SLA
- 44 languages with instant voice cloning; locale-aware numbers/dates
- Artificial Analysis: #1 at ~1279 Elo (25 Sept 2026), #2 (1275) behind Eleven v4 on 29 Sept
- sonic-2, sonic-turbo and sonic-3 snapshots sunset 2026-10-20
What happened
Cartesia updated its Sonic TTS again: Sonic-3.5 in May, Sonic-3.6 in August. The update focused on naturalness, accent retention and faithful reading of structured content.
Why it matters
Voice-agent TTS competition moved fast in Aug-Sept 2026. Cartesia, Inworld (TTS-2), Google (Gemini 3.8 Flash TTS), Alibaba and ElevenLabs (v4) swapped the Artificial Analysis #1 spot within weeks. Cartesia's SSM architecture is the main non-transformer contender at the frontier.
Changelog
- 2026-09-29: created
Models
- Cartesia Sonic-3.6 Cartesia · current
Related events
- ElevenLabs launches Eleven v4 and Eleven v4 Turbo, #1 on Artificial Analysis TTS arena ★★★★
- Google ships Gemini 3.8 Live voice models and Gemini 3.8 Flash TTS with voice design and cloning ★★
- Inworld Realtime TTS-2 reaches GA with audio-aware, prompt-directed speech ★★★
- Alibaba's Qwen-Audio-3.0-TTS takes #1 on the Artificial Analysis text-to-speech leaderboard ★★★
- Deepgram launches Flux TTS and passes $100M ARR ★★★
- Artificial Analysis launches the Speech Agent Arena for speech-to-speech voice agents ★★
Sources (4)
- officialCartesia: Introducing Sonic-3.6
- docsCartesia docs: Sonic 3.6
- officialCartesia: Introducing Ink-2
- officialArtificial Analysis TTS leaderboard
id: 2026-08-27-cartesia-sonic-3-6 · updated 2026-09-29 · open in the interactive timeline