Cartesia vs Google
Cartesia rates higher than every Gemini TTS model, and generates speech faster.
ServiceNow, Decagon, and Quora run their production voice agents on Cartesia, with first audio in under 90ms.
Voice quality
Cartesia rates higher than every Gemini TTS model
- The Provider Voice Arena rates every model on its own voices, so a voice roster counts alongside the model that speaks it.
- Google sells its text to speech on lifelike voices. On a blind listening test, Sonic 3.6 rates first of the 90 models on the board, above Gemini 3.1 Flash TTS and every earlier Gemini TTS model.
Provider Voice Arena Elo
Higher is better
Speed
Cartesia generates about five times as fast as Google's best-rated model
- Artificial Analysis times generation for every model on the board, so both sides run through the same harness.
- Generating well ahead of playback is what keeps a long turn from stalling mid-sentence. Of the two Gemini TTS models Artificial Analysis has timed, the one it rates highest for quality is the slower.
Characters per second
Higher is better
Reasons why companies choose Cartesia over Gemini TTS
Human-like naturalness
Intonation, pacing, pronunciation, emotion, and audio quality that drive higher completion rates
Cartesia1275 EloGemini TTS1202 EloGemini 3.1 Flash TTS1077 EloGemini 2.5 Flash Lite TTS1049 EloGemini 2.5 Flash TTSSeptember 2026
Model maturity
Whether the model you benchmark is the model you can ship on.
CartesiaSonic 3.6 is the default model on the public APIGemini TTSAll three Gemini TTS models Google documents are preview releasesCustom voices
How much audio it takes, and who is allowed to use one.
CartesiaInstant clone from 10 seconds, professional clone from 30 minutes, on the public APIGemini TTSGemini TTS has 30 prebuilt voices and no cloning. Cloud Text-to-Speech cloning is restricted to allow-listed users, through sales.Streaming
Whether audio starts playing before the whole turn has been generated.
CartesiaEvery Sonic model streamsGemini TTSStreaming starts at Gemini 3.1. The earlier Gemini TTS models return the finished clip.Deployment
Decides whether regulated teams can use it at all.
CartesiaVPC, on-prem, on-device, or air-gapped, behind a 99.9% uptime SLAGemini TTSGoogle Cloud, Vertex AI, and the Gemini API
Frequently asked questions
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