{"schema":"postcutoff/event@1","as_of":"2026-11-13T13:49:00+01:00","url":"https://postcutoff.com/e/2026-08-31-inworld-realtime-tts-2/","md":"https://postcutoff.com/e/2026-08-31-inworld-realtime-tts-2/index.md","disclosure":{"written_by":"AI agents (Claude Opus 5.5 in Claude Code)","editor":"human editor","policy":"https://postcutoff.com/about/"},"license":null,"id":"2026-08-31-inworld-realtime-tts-2","date":"2026-08-31","date_precision":"day","short_title":"Inworld Realtime TTS-2 reaches GA with audio-aware, prompt-directed speech","deck":null,"takeaway":"Inworld AI made Realtime TTS-2 (inworld-tts-2) and TTS-2 Flash generally available on 2026-08-31 after a research preview on 2026-05-05.","category":"model-release","category_label":"Model releases","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":[{"n":1,"title":"Inworld: Realtime TTS-2","url":"https://inworld.ai/blog/realtime-tts-2","type":"official","group":"primary","domain":"inworld.ai"},{"n":2,"title":"Inworld docs: TTS models","url":"https://docs.inworld.ai/tts/tts-models","type":"docs","group":"primary","domain":"docs.inworld.ai"},{"n":3,"title":"Inworld pricing","url":"https://inworld.ai/pricing","type":"official","group":"primary","domain":"inworld.ai"},{"n":4,"title":"Yahoo Finance: AI research lab Inworld acquires Ultravox","url":"https://finance.yahoo.com/technology/ai/articles/ai-research-lab-inworld-acquires-211500825.html","type":"press","group":"press","domain":"finance.yahoo.com"},{"n":5,"title":"MarkTechPost: preview launch (2026-05-05)","url":"https://www.marktechpost.com/2026/05/05/inworld-ai-launches-realtime-tts-2-a-closed-loop-voice-model-that-adapts-to-how-you-actually-talk/","type":"press","group":"press","domain":"marktechpost.com"}],"official":3,"filed":"2026-09-29","updated":"2026-10-03","orgs":["Inworld AI"],"title":"Inworld Realtime TTS-2 reaches GA with audio-aware, prompt-directed speech","summary":"Inworld AI made Realtime TTS-2 (`inworld-tts-2`) and TTS-2 Flash generally available on 2026-08-31 after a research preview on 2026-05-05. TTS-2 conditions on the actual audio of earlier turns, so it can pick up a user's tone and pacing. It takes plain-English voice direction and keeps one voice identity across 100+ languages, at $25 (Flash $15) per 1M characters pay-as-you-go.","key_facts":["Oct 1, 2026: Inworld acquired Ultravox, a platform for building real-time voice agents (turn-taking, interruptions); Ultravox customers get Realtime TTS-2; terms not disclosed","Model id inworld-tts-2; endpoint POST https://api.inworld.ai/tts/v1/voice","TTS-2 median TTFA <200 ms; Flash ~20 ms TTFB (docs)","Voice cloning from 5-15 s; voice design from text; STABLE/BALANCED/CREATIVE modes","Artificial Analysis 29 Sept 2026: #5 (Elo 1244); Inworld's earlier TTS 1.5 had been #1","TTS-1..1.5 discontinued 2026-06-15; Inworld also offers migration from shut-down PlayHT"],"key_numbers":[],"tags":["tts","speech","voice-agents","voice"],"science":null,"body_md":"## What happened\n\nInworld promoted TTS-2 from research preview to GA and added a Flash variant for latency- and cost-sensitive agents.\n\n## Why it matters\n\nTTS-2 closes the loop between listening and speaking in a cascaded voice stack: the TTS hears the user, not just the transcript. The price is also well under ElevenLabs' list price.","disputed":[],"related":[{"id":"2026-09-28-elevenlabs-eleven-v4","url":"https://postcutoff.com/e/2026-09-28-elevenlabs-eleven-v4/","date":"2026-09-28","date_precision":"day","short_title":"ElevenLabs launches Eleven v4 and Eleven v4 Turbo, #1 on Artificial Analysis TTS arena","deck":null,"takeaway":null,"category":"model-release","category_label":"Model releases","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":11,"official":7,"filed":"2026-09-29","updated":"2026-09-29","orgs":["ElevenLabs"]},{"id":"2026-08-27-cartesia-sonic-3-6","url":"https://postcutoff.com/e/2026-08-27-cartesia-sonic-3-6/","date":"2026-08-27","date_precision":"day","short_title":"Cartesia Sonic-3.6 goes GA and tops the Artificial Analysis Speech Arena","deck":null,"takeaway":"Cartesia made Sonic-3.6 generally available on 2026-08-27 (beta 2026-08-17), three months after Sonic-3.5.","category":"model-release","category_label":"Model releases","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Confirmed"]},"sources":4,"official":4,"filed":"2026-09-29","updated":"2026-09-29","orgs":["Cartesia"]}],"people":[],"posts":[],"videos":[],"models":[{"id":"inworld-tts-2","name":"Inworld Realtime TTS-2 / TTS-2 Flash","url":"https://postcutoff.com/m/inworld-tts-2/"}],"changes":[{"date":"2026-10-03","type":"edit","text":"Added the Ultravox acquisition (Oct 1)"},{"date":"2026-09-29","type":"filed","text":"Created"}],"provenance":{"agents":[{"model":"Claude Opus 5.5","maker":"Anthropic","tool":"Claude Code"}],"filed":"2026-09-29","run":null,"sources_read":null,"updated":"2026-10-03","human_review":null,"version":{"date":"2026-10-04"}},"gaps":[{"model_id":"gpt-6-astra","name":"GPT-6 Astra","cutoff":"2026-04","days_after":123,"in_training_data":false},{"model_id":"claude-opus-5-5","name":"Claude Opus 5.5","cutoff":"2026-06","days_after":62,"in_training_data":false},{"model_id":"gemini-4-hydrogen","name":"Gemini 4 Hydrogen","cutoff":"2026-03","days_after":153,"in_training_data":false},{"model_id":"grok-4-7","name":"Grok 4.7","cutoff":"2026-05","days_after":92,"in_training_data":false}],"short_url":null}