Listeners rate Cartesia's Sonic 3.6 above every Inworld Realtime TTS-2 model.

Listeners rate Sonic 3.6 higher. On the Artificial Analysis Provider Voice Arena, where listeners compare two clips without knowing which model produced either, Sonic 3.6 scores 1279 against 1249 for Realtime TTS-2 and 1217 for Realtime TTS-2 Flash, as of October 2026.

It comes from Artificial Analysis, an independent benchmark. Listeners hear two clips of the same line without being told which model produced either, and pick the one they prefer. The Provider Voice Arena lets every model speak in its own voices.

44 languages from one model, including English, Spanish, French, German, and Japanese. Accents are calibrated per region rather than bolted onto an English model, so Spanish for Mexico City and Spanish for Madrid are not the same voice.

Yes. Cartesia deploys on-prem and air-gapped, which teams in healthcare, finance, and government use to keep audio inside their own network, backed by a 99.9% uptime SLA.

One to two weeks for most teams. Cartesia is integrated into the major voice agent platforms and every model is on the public API, so there is no platform to move onto and nothing to unpick later.