Voice AI BenchmarksBy

CARTESIATEXT-TO-SPEECH2,240 SAMPLES / 30 DAYSLAST RUN AUG 28, 2026, 21:30 UTC

Sonic 3.6 text-to-speech benchmarks

Coval has active text-to-speech measurements for Sonic 3.6, created by Cartesia and served through Cartesia's own API.

Time to First Audio#22 / 30
466ms
TTFA Network Roundtrip#19 / 28
324ms
TTFA Leading Silence#23 / 28
142ms
Word Error Rate#23 / 30
5.5%

Overview

Sonic 3.6 is tested every day on a fixed set of text prompts, measuring how quickly audible speech starts and how intelligible the result is.

Technical specifications

Made by
Cartesia
Hosted by
Cartesia
Source
Official API
Licensing
Proprietary
Deployment
On-prem
Region
US
Features
Multilingual, Voice cloning, Emotion control

How Sonic 3.6 ranks

Full TTS dashboard
Time to First Audio — every measured TTS modelMilliseconds · lower is better · 30-day averageEvery TTS model ranked on Time to First Audio, with Sonic 3.6 highlighted.
  1. #1Palabra TTS v1116 ms
  2. #2vui124 ms
  3. #3TTS Flash 2128 ms
  4. #4TTS 2176 ms
  5. #5Blizzard235 ms
  6. #6Neural236 ms
  7. #7Mist v3256 ms
  8. #8TTS Rt v2262 ms
  9. #9Sonic 3.5274 ms
  10. #10TTS RT v1275 ms
  11. #11Dragon HD Latest310 ms
  12. #12Coda313 ms
  13. #13Aura 2328 ms
  14. #14S2.1 Pro374 ms
  15. #15Default384 ms
  16. #16Speech 2.8 Turbo411 ms
  17. #17Eleven v3 Conversational412 ms
  18. #18Grok TTS420 ms
  19. #19S1434 ms
  20. #20Flash v2.5455 ms
  21. #21Speech 2.8 HD460 ms
  22. #22Sonic 3.6466 ms
Show all 30 models
  1. #23Simba 3.2484 ms
  2. #24Chirp 3 HD512 ms
  3. #25Simba 3.0526 ms
  4. #26Falcon 2549 ms
  5. #27Lightning v3.1 Pro586 ms
  6. #28Qwen3 TTS Flash Realtime645 ms
  7. #29S2.1 Pro Free806 ms
  8. #30GPT-4o mini TTS1075 ms
median of all models · 397 ms
TTS models over the last 30 days, ranked on Time to First Audio.
#ModelHostTTFAWERSamples
1Palabra TTS v1Palabra116 ms5.9%14,396
2vuiFluxions124 ms8,624
3TTS Flash 2Inworld AI128 ms8,719
4TTS 2Inworld AI176 ms4.8%14,529
5BlizzardLmnt235 ms7.4%14,117
6NeuralAzure236 ms4.3%3,350
7Mist v3Rime256 ms6.3%14,524
8TTS Rt v2Soniox262 ms8,849
9Sonic 3.5Cartesia274 ms6.1%14,513
10TTS RT v1Soniox275 ms3.7%14,528
11Dragon HD LatestAzure310 ms5.1%3,350
12CodaRime313 ms5.2%14,523
13Aura 2Deepgram328 ms5.3%14,501
14S2.1 ProFish Audio374 ms10,222
15DefaultGradium384 ms4.6%14,002
16Speech 2.8 TurboMiniMax411 ms4.8%1,997
17Eleven v3 ConversationalElevenLabs412 ms6,750
18Grok TTSxAI420 ms4.7%14,524
19S1Fish Audio434 ms4.9%10,236
20Flash v2.5ElevenLabs455 ms6.7%9,259
21Speech 2.8 HDMiniMax460 ms1,995
22Sonic 3.6Cartesia466 ms560
23Simba 3.2Speechify484 ms4.7%14,525
24Chirp 3 HDGoogle512 ms5.2%14,530
25Simba 3.0Speechify526 ms5.3%14,526
26Falcon 2Murf549 ms10,229
27Lightning v3.1 ProSmallest586 ms4.4%14,515
28Qwen3 TTS Flash RealtimeAlibaba645 ms8.8%14,530
29S2.1 Pro FreeFish Audio806 ms4.7%14,464
30GPT-4o mini TTSOpenAI1075 ms4.8%14,517
Under-sampled models are excluded; tied models share a place. Dotted WER values split into substitutions, deletions and insertions on hover or tap.

Latency vs accuracy

TTFA vs WEREach point is one measured model · Sonic 3.6 highlighted · 30-day averagesTime to First Audio against Word Error Rate for every measured TTS model, with Sonic 3.6 highlighted.
Palabra TTS v1 — 116 ms, 5.9%vui — 124 ms, 7.9%TTS Flash 2 — 128 ms, 4.9%TTS 2 — 176 ms, 4.8%Blizzard — 235 ms, 7.4%Neural — 236 ms, 4.3%Mist v3 — 256 ms, 6.3%TTS Rt v2 — 262 ms, 3.9%Sonic 3.5 — 274 ms, 6.1%TTS RT v1 — 275 ms, 3.7%Dragon HD Latest — 310 ms, 5.1%Coda — 313 ms, 5.2%Aura 2 — 328 ms, 5.3%S2.1 Pro — 374 ms, 4.6%Default — 384 ms, 4.6%Speech 2.8 Turbo — 411 ms, 4.8%Eleven v3 Conversational — 412 ms, 4.4%Grok TTS — 420 ms, 4.7%S1 — 434 ms, 4.9%Flash v2.5 — 455 ms, 6.7%Speech 2.8 HD — 460 ms, 4.7%Simba 3.2 — 484 ms, 4.7%Chirp 3 HD — 512 ms, 5.2%Simba 3.0 — 526 ms, 5.3%Falcon 2 — 549 ms, 5.2%Lightning v3.1 Pro — 586 ms, 4.4%Qwen3 TTS Flash Realtime — 645 ms, 8.8%S2.1 Pro Free — 806 ms, 4.7%GPT-4o mini TTS — 1075 ms, 4.8%Sonic 3.6 — 466 ms, 5.5%

Where the errors come from

WER compositionSonic 3.6's Word Error Rate split by error type · 30-day averageSonic 3.6's WER split into substitutions, deletions and insertions.
  • Sonic 3.65.5%
SubstitutionsDeletionsInsertions

Averages and tail latency

Averages hide slow outliers — these are the distributions behind each figure.

Sonic 3.6 latency distributionMilliseconds · shared axis across metrics · last 30 daysSonic 3.6's latency percentiles per metric: p25–p75 band, p50 tick, whisker to p99.
  • Time to First Audiop50 442 ms · p99 945 ms
  • TTFA Network Roundtripp50 304 ms · p99 804 ms
  • TTFA Leading Silencep50 142 ms · p99 211 ms
band p25–p75 · tick p50 · whisker to p99 with p90 and p95 stops
Average and percentile values per metric, with the number of samples behind each row.
MetricAveragep25p50p75p90p95p99Samples
Time to First Audio466 ms381 ms442 ms540 ms626 ms746 ms945 ms560
TTFA Network Roundtrip324 ms238 ms304 ms401 ms466 ms567 ms804 ms560
TTFA Leading Silence142 ms130 ms142 ms154 ms170 ms184 ms211 ms560
Word Error Rate5.5%0.0%0.0%10.5%20.0%25.0%36.4%560

Time to First Audio by dataset

Sonic 3.6 by test conditionMilliseconds · lower is better · best condition firstSonic 3.6's Time to First Audio on each benchmark dataset.
  1. Text prompts466 ms
Time to First Audio per dataset, with the number of samples behind each figure.
DatasetTTFASamples
Text prompts466 ms560

Strongest condition: Text prompts at 466 ms · weakest: Text prompts at 466 ms.

Results are re-measured daily using fixed datasets and reported over a rolling 30-day window. Same datasets, prompts and metric definitions for every model, measured by Coval’s open-source runner. Full methodology on the overview.

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