Cartesia Sonic-3.6 goes GA and tops the Artificial Analysis Speech Arena
Confirmed
The takeaway
Cartesia made Sonic-3.6 generally available on 2026-08-27 (beta 2026-08-17), three months after Sonic-3.5.
Status
- Claim
Confirmed
- Our reporting
- High confidence
- Importance
- 3 of 5
- Last verified
- 29 September 2026
Your AI and this story
- GPT-6 Astra119 days after its cutoff
- Claude Opus 5.558 days after its cutoff
- Gemini 4 Hydrogen149 days after its cutoff
- Grok 4.788 days after its cutoff
None of these four assistants can know about it. The closest, Claude Opus 5.5, stops 58 days before it.
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.
Sources
4 sources from 3 sites. Numbers match the chips in the text.
4 sources: 4 primary
Primary
- Cartesia: Introducing Sonic-3.6cartesia.ai, official
- Cartesia docs: Sonic 3.6docs.cartesia.ai, docs
- Cartesia: Introducing Ink-2cartesia.ai, official
- Artificial Analysis TTS leaderboardartificialanalysis.ai, official
Changes
- Filed