Voice AI BenchmarksBy

PROVIDERLAST 30 DAYS

official resource

Cartesia voice AI models and benchmarks

Cartesia lists 3 STT and TTS models in Coval. Fastest dated mean latency over 30 days: STT: Ink 2 at 149 ms TTFS, with 3.6% WER. TTS: Sonic 3.5 at 293 ms TTFA, with 1.5% WER. Coval benchmarks hosted endpoints daily using a consistent evaluation methodology. Last measured .

Cartesia builds real-time speech models for both sides of a voice interaction: Ink transcription and Sonic synthesis.

Measured models
3
STTTTS
Best STT model#13 / 29
149ms
Ink 2
Best TTS model#18 / 32
293ms
Sonic 3.5

Overview

Cartesia creates and hosts the measured Ink and Sonic endpoints and offers on-premises options for both model families.

Every model below is measured daily on the same fixed inputs and ranked against the full field, never blended into a company score.

Model lineup

Speech-to-Text
Ink 2
Text-to-Speech
Sonic 3.5, Sonic 3.6

Speech-to-Text

Full STT dashboard

Ranked on Time to Final Segment against 29 measured models.

Time to Final Segmentms · lower is better · Cartesia models markedEvery measured STT model on Time to Final Segment, with Cartesia's models highlighted.
  1. #1Qwen3 ASR 1.7b39 ms
  2. #2STT RT v544 ms
  3. #3Qwen3 ASR Fast47 ms
  4. #4STT 167 ms
  5. #5Nova 385 ms
  6. #6Nova 287 ms
  7. #7Parakeet TDT 0.6B v397 ms
  8. #13Ink 2149 ms
leaders plus Cartesia models · 21 other models in the full table
Word Error Rate% · lower is better · Cartesia models markedEvery measured STT model on Word Error Rate, with Cartesia's models highlighted.
  1. #1Universal 3.6 Pro2.1%
  2. #2Universal 3.5 Pro2.4%
  3. #3Qwen3 ASR Fast2.6%
  4. #4resonant-12.6%
  5. #5Qwen3 ASR 1.7b2.9%
  6. #6Gemini 3.5 Transcribe Live3.0%
  7. #7Chirp 33.2%
  8. #8Ink 23.6%
leaders plus Cartesia models · 23 other models in the full table
Time to First Tokenms · lower is better · Cartesia models markedEvery measured STT model on Time to First Token, with Cartesia's models highlighted.
  1. #1Whisper Large v3via Baseten924 ms
  2. #2Qwen3 ASR 1.7b946 ms
  3. #3Universal 3.5 Pro1025 ms
  4. #4Universal 3.6 Pro1071 ms
  5. #5Flux1091 ms
  6. #6Flux Multilingual1165 ms
  7. #7STT 11199 ms
  8. #21Ink 21970 ms
leaders plus Cartesia models · 19 other models in the full table
TTFS vs WER — Cartesia vs every measured modelEach point is one measured STT model · Cartesia models highlighted · 30-day averagesTime to Final Segment against Word Error Rate for every measured STT model, with Cartesia's models highlighted.
Qwen3 ASR 1.7b — 39 ms, 2.9%STT RT v5 — 44 ms, 4.8%Qwen3 ASR Fast — 47 ms, 2.6%STT 1 — 67 ms, 7.1%Nova 3 — 85 ms, 5.3%Nova 2 — 87 ms, 6.7%Parakeet TDT 0.6B v3 — 97 ms, 11.1%Flux Multilingual — 98 ms, 7.5%Flux — 98 ms, 5.8%Scribe v2 Realtime — 121 ms, 4.4%Whisper Large v3 via Baseten — 131 ms, 4.5%Universal 3.6 Pro — 135 ms, 2.1%Universal 3.5 Pro — 170 ms, 2.4%Whisper Large v3 via Together AI — 196 ms, 7.4%Pulse — 205 ms, 4.6%Grok STT — 222 ms, 4.1%resonant-1 — 252 ms, 2.6%Default — 262 ms, 8.8%Linden 1 — 275 ms, 3.9%Gemini 3.5 Transcribe Live — 319 ms, 3.0%Daytona STT — 399 ms, 4.9%Voxtral Mini Transcribe Realtime 2602 — 416 ms, 5.4%GPT Realtime Whisper — 599 ms, 4.0%Solaria 1 — 614 ms, 6.1%GPT-4o mini Transcribe — 711 ms, 3.9%Chirp 3 — 768 ms, 3.2%GPT-4o Transcribe — 784 ms, 3.7%Chirp 2 — 910 ms, 3.9%Ink 2 — 149 ms, 3.6%
Benchmarked models with their Time to Final Segment over the last 30 days.
ModelHostTTFSRank
Ink 2Cartesia149 ms13th of 29

Text-to-Speech

Full TTS dashboard

Ranked on Time to First Audio against 32 measured models.

Time to First Audioms · lower is better · Cartesia models markedEvery measured TTS model on Time to First Audio, with Cartesia's models highlighted.
  1. #1vui59 ms
  2. #2Default63 ms
  3. #3Qwen3 TTS Fast68 ms
  4. #4TTS Flash 291 ms
  5. #5Qwen3 TTS 1.7b107 ms
  6. #6Simba 3.0111 ms
  7. #7Palabra TTS121 ms
  8. #18Sonic 3.5293 ms
  9. #21Sonic 3.6299 ms
leaders plus Cartesia models · 23 other models in the full table
Word Error Rate% · lower is better · Cartesia models markedEvery measured TTS model on Word Error Rate, with Cartesia's models highlighted.
  1. #1Sonic 3.61.5%
  2. #2S2.1 Pro Free1.5%
  3. #3S2.1 Pro1.5%
  4. #4Simba 3.01.5%
  5. #5Lightning v3.1 Pro1.5%
  6. #6Sonic 3.51.5%
  7. #7Chirp 3 HD1.5%
leaders plus Cartesia models · 25 other models in the full table
TTFA vs WER — Cartesia vs every measured modelEach point is one measured TTS model · Cartesia models highlighted · 30-day averagesTime to First Audio against Word Error Rate for every measured TTS model, with Cartesia's models highlighted.
vui — 59 ms, 2.1%Default — 63 ms, 1.9%Qwen3 TTS Fast — 68 ms, 1.8%TTS Flash 2 — 91 ms, 1.7%Qwen3 TTS 1.7b — 107 ms, 1.8%Simba 3.0 — 111 ms, 1.5%Palabra TTS — 121 ms, 2.6%Simba 3.2 — 126 ms, 1.9%drama3-preview — 168 ms, 1.9%TTS 2 — 190 ms, 1.6%Flash v2.5 — 192 ms, 1.8%Eleven v4 Turbo — 200 ms, 1.7%Flux TTS — 205 ms, 1.7%TTS RT v1 — 254 ms, 2.4%TTS Rt v2 — 256 ms, 2.4%Mist v3 — 287 ms, 2.1%Phantom Z 3.4 conversational — 287 ms, 1.8%Falcon 2 — 296 ms, 1.7%Aura 2 — 297 ms, 1.8%Coda — 332 ms, 9.5%S2.1 Pro — 342 ms, 1.5%Grok TTS — 362 ms, 1.6%S1 — 390 ms, 1.8%Lightning v3.1 Pro — 392 ms, 1.5%Daytona TTS — 486 ms, 1.6%Aura 2 En — 568 ms, 2.1%Chirp 3 HD — 599 ms, 1.5%Qwen3 TTS Flash Realtime — 718 ms, 3.0%S2.1 Pro Free — 848 ms, 1.5%GPT-4o mini TTS — 2582 ms, 1.8%Sonic 3.5 — 293 ms, 1.5%Sonic 3.6 — 299 ms, 1.5%
Benchmarked models with their Time to First Audio over the last 30 days.
ModelHostTTFARank
Sonic 3.5Cartesia293 ms18th of 32
Sonic 3.6Cartesia299 ms21st of 32

How fast are Cartesia's STT and TTS models?

Ink 2 measures mean 149 ms time to final segment (13th of 29) among STT systems. Last measured 2026-10-15. Sonic 3.5 measures mean 293 ms time to first audio (18th of 32) among TTS systems. Last measured 2026-10-15. Sonic 3.6 measures mean 299 ms time to first audio (21st of 32) among TTS systems. Last measured 2026-10-15.

How accurate are Cartesia's STT and TTS models?

Ink 2 measures 3.6% word error rate (8th of 31) among STT systems. Last measured 2026-10-15. Sonic 3.6 measures 1.5% word error rate (1st of 32) among TTS systems. Last measured 2026-10-15. Sonic 3.5 measures 1.5% word error rate (6th of 32) among TTS systems. Last measured 2026-10-15.

Which Cartesia model is fastest?

Its fastest dated STT result is Ink 2 at mean 149 ms time to final segment (13th of 29) among STT systems, with 3.6% WER. Last measured 2026-10-15. Its fastest dated TTS result is Sonic 3.5 at mean 293 ms time to first audio (18th of 32) among TTS systems, with 1.5% WER. Last measured 2026-10-15.

Limits of this comparison

Coval compares each model only within its STT or TTS category.

  • The results do not represent an end-to-end Cartesia agent and do not add Ink and Sonic latency into one figure.

Official resources

Same datasets, prompts and metric definitions for every model, measured by Coval’s open-source runner. Full methodology on the overview.

Evaluate your own voice agent

Use Coval to test your production configuration, prompts and calls—not only the public benchmark endpoints.

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