Question 1

What is Cartesia Sonic?

Accepted Answer

Cartesia Sonic is a text-to-speech model from Cartesia, released on 29 May 2024. Sub-100ms time-to-first-byte — built for realtime voice agents.

Question 2

When was Cartesia Sonic released?

Accepted Answer

Cartesia Sonic was released by Cartesia on 29 May 2024.

Question 3

How much does Cartesia Sonic cost?

Accepted Answer

Cartesia Sonic costs about $0.07 per 1,000 characters of generated audio (~150–200 spoken words). A 1,000-word voiceover therefore runs roughly $0.39.

Question 4

What is Cartesia Sonic best for?

Accepted Answer

Cartesia Sonic is most useful for realtime voice agents and live conversations. Its key strengths are fastest ttfb on the market and voice cloning.

Question 5

How fast is Cartesia Sonic?

Accepted Answer

Cartesia Sonic with a typical time-to-first-token of 90 ms on the major API providers.

Question 6

Is Cartesia Sonic better than OpenAI TTS (HD)?

Accepted Answer

Cartesia Sonic and OpenAI TTS (HD) target slightly different workloads — see the full breakdown for benchmark scores and pricing. See our full Cartesia Sonic vs OpenAI TTS (HD) comparison at /ai-models/compare/cartesia-sonic-vs-openai-tts/.

Question 7

What is the best alternative to Cartesia Sonic?

Accepted Answer

The closest alternatives to Cartesia Sonic are OpenAI TTS (HD), ElevenLabs Multilingual v2 and GPT-5.5. Each shares most of Cartesia Sonic’s use-cases — pick by price, context window or specific capability rather than headline intelligence.

Question 8

Is Cartesia Sonic open source?

Accepted Answer

No. Cartesia Sonic is proprietary — the weights are not released. Access is via Cartesia’s own API and partner platforms. For open-weights alternatives in the same tier, see our open-source AI models page.

Question 9

Can I use Cartesia Sonic for free?

Accepted Answer

Cartesia Sonic offers a small free tier (typically a few minutes / images per month) via its consumer product. Beyond the free tier it’s billed per second of video / per minute of audio / per generated image.

Cartesia Sonic

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