Voice AI BenchmarksBy

INWORLD AITEXT-TO-SPEECH7,758 SAMPLES / 30 DAYSLAST RUN OCT 16, 2026, 22:30 UTC

official resource

TTS 2 text-to-speech benchmarks

TTS 2, hosted by Inworld AI, measures mean 186 ms time to first audio (10th of 32) and 1.6% word error rate (9th of 32) among TTS systems. Results cover the last 30 days. Coval benchmarks hosted endpoints daily using a consistent evaluation methodology. Last measured .

Inworld TTS 2 is Inworld's full synthesis model for interactive applications.

Time to First Audio#10 / 32
186ms
TTFA Network Roundtrip#12 / 32
132ms
TTFA Leading Silence#14 / 32
54ms
Word Error Rate#9 / 32
1.6%

Overview

Inworld offers multilingual voices, cloning and emotion controls. The standard and Flash endpoints are measured separately.

TTS 2 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
Inworld AI
Hosted by
Inworld AI
Source
Official API
Licensing
Proprietary
Deployment
Cloud
Region
US
Features
Emotion control, Multilingual, Voice cloning

How TTS 2 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 TTS 2 highlighted.
  1. #1vui57 ms
  2. #2Default63 ms
  3. #3Qwen3 TTS Fast67 ms
  4. #4TTS Flash 288 ms
  5. #5Qwen3 TTS 1.7b107 ms
  6. #6Simba 3.0110 ms
  7. #7Palabra TTS121 ms
  8. #8Simba 3.2125 ms
  9. #9drama3-preview185 ms
  10. #10TTS 2186 ms
  11. #11Flash v2.5193 ms
  12. #12Eleven v4 Turbo199 ms
Show all 32 models
  1. #13Flux TTS204 ms
  2. #14TTS RT v1255 ms
  3. #15TTS Rt v2256 ms
  4. #16Phantom Z 3.4 conversational268 ms
  5. #17Falcon 2282 ms
  6. #18Mist v3287 ms
  7. #19Sonic 3.5292 ms
  8. #20Aura 2297 ms
  9. #21Sonic 3.6297 ms
  10. #22Coda332 ms
  11. #23S2.1 Pro343 ms
  12. #24Grok TTS361 ms
  13. #25S1391 ms
  14. #26Lightning v3.1 Pro392 ms
  15. #27Daytona TTS485 ms
  16. #28Aura 2 En565 ms
  17. #29Chirp 3 HD598 ms
  18. #30Qwen3 TTS Flash Realtime719 ms
  19. #31S2.1 Pro Free849 ms
  20. #32GPT-4o mini TTS2568 ms
median of all models · 275 ms
TTS models over the last 30 days, ranked on Time to First Audio.
#ModelHostTTFAWERSamples
1vuiFluxions57 ms1,964
2Gradium TTS Beta 202609Gradium63 ms2,136
3Qwen3 TTS FastNari Labs67 ms2,136
4TTS Flash 2Inworld AI88 ms1,940
5Qwen3 TTS 1.7bBaseten107 ms1,440
6Simba 3.0SpeechifyAI110 ms2,133
7Palabra TTS v1Palabra121 ms1,759
8Simba 3.2SpeechifyAI125 ms2,130
9Drama 3 Preview Us EastFish Audio185 ms382
10TTS 2Inworld AI186 ms1,940
11Flash v2.5ElevenLabs193 ms2,126
12Eleven v4 TurboElevenLabs199 ms1,446
13Flux TTSDeepgram204 ms1,991
14TTS RT v1Soniox255 ms1,804
15TTS Rt v2Soniox256 ms1,801
16Phantom Z 3.4 conversationalDeepdub268 ms1,871
17Falcon 2Murf282 ms2,135
18Mist v3Rime287 ms602
19Sonic 3.5Cartesia292 ms2,136
20Aura 2Deepgram297 ms2,068
21Sonic 3.6Cartesia297 ms2,136
22CodaRime332 ms602
23S2.1 ProFish Audio343 ms2,136
24Grok TTSSpaceXAI361 ms2,131
25S1Fish Audio391 ms2,135
26Lightning v3.1 ProSmallest392 ms2,136
27Daytona TTSGuava485 ms1,344
28Aura 2 EnCloudflare565 ms2,135
29Chirp 3 HDGoogle598 ms2,136
30Qwen3 TTS Flash RealtimeAlibaba719 ms2,135
31S2.1 Pro FreeFish Audio849 ms2,129
32GPT-4o mini TTSOpenAI2568 ms2,014
Under-sampled models are excluded; tied models share a place. Dotted WER values split into substitutions, deletions and insertions on hover or tap.

Highest relative placement: 9th of 32 on Word Error Rate.

Latency vs accuracy

TTFA vs WEREach point is one measured model · TTS 2 highlighted · 30-day averagesTime to First Audio against Word Error Rate for every measured TTS model, with TTS 2 highlighted.
vui — 57 ms, 2.1%Default — 63 ms, 1.9%Qwen3 TTS Fast — 67 ms, 1.8%TTS Flash 2 — 88 ms, 1.7%Qwen3 TTS 1.7b — 107 ms, 1.8%Simba 3.0 — 110 ms, 1.6%Palabra TTS — 121 ms, 2.7%Simba 3.2 — 125 ms, 2.0%drama3-preview — 185 ms, 1.9%Flash v2.5 — 193 ms, 1.8%Eleven v4 Turbo — 199 ms, 1.7%Flux TTS — 204 ms, 1.7%TTS RT v1 — 255 ms, 2.5%TTS Rt v2 — 256 ms, 2.4%Phantom Z 3.4 conversational — 268 ms, 1.9%Falcon 2 — 282 ms, 1.7%Mist v3 — 287 ms, 2.1%Sonic 3.5 — 292 ms, 1.6%Aura 2 — 297 ms, 1.9%Sonic 3.6 — 297 ms, 1.5%Coda — 332 ms, 9.5%S2.1 Pro — 343 ms, 1.6%Grok TTS — 361 ms, 1.6%S1 — 391 ms, 1.8%Lightning v3.1 Pro — 392 ms, 1.6%Daytona TTS — 485 ms, 1.7%Aura 2 En — 565 ms, 2.1%Chirp 3 HD — 598 ms, 1.6%Qwen3 TTS Flash Realtime — 719 ms, 3.0%S2.1 Pro Free — 849 ms, 1.5%GPT-4o mini TTS — 2568 ms, 1.8%TTS 2 — 186 ms, 1.6%

Where the errors come from

WER compositionTTS 2's Word Error Rate split by error type · 30-day averageTTS 2's WER split into substitutions, deletions and insertions.
  • TTS 21.6%
SubstitutionsDeletionsInsertions

Averages and tail latency

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

TTS 2 latency distributionMilliseconds · shared axis across metrics · last 30 daysTTS 2's latency percentiles per metric: p25–p75 band, p50 tick, whisker to max.
  • Time to First Audiop50 149 ms · Max 31952 ms
  • TTFA Network Roundtripp50 94 ms · Max 31910 ms
  • TTFA Leading Silencep50 53 ms · Max 137 ms
band p25–p75 · tick p50 · whisker to max with p90 and p95 stops
Average and percentile values per metric, with the number of samples behind each row.
MetricAveragep25p50p75p90p95MaxSamples
Time to First Audio186 ms134 ms149 ms167 ms181 ms192 ms31952 ms1,940
TTFA Network Roundtrip132 ms87 ms94 ms101 ms110 ms122 ms31910 ms1,940
TTFA Leading Silence54 ms42 ms53 ms71 ms80 ms84 ms137 ms1,940
Word Error Rate1.6%0.0%0.0%2.1%7.7%12.5%43.8%1,938

Last 30 days

Daily medians from the same measurement runs · gaps are days without qualifying runs.

Time to First Audio — daily p50Line p50 · band p25–p75 · UTC daysTTS 2's daily median Time to First Audio over the last 30 days.
TTS 2 · Sep 23: 143 msTTS 2 · Sep 24: 161 msTTS 2 · Sep 25: 148 msTTS 2 · Sep 26: 166 msTTS 2 · Sep 27: 142 msTTS 2 · Sep 28: 152 msTTS 2 · Sep 30: 144 msTTS 2 · Oct 1: 150 msTTS 2 · Oct 2: 156 msTTS 2 · Oct 3: 145 msTTS 2 · Oct 4: 167 msTTS 2 · Oct 5: 159 msTTS 2 · Oct 6: 139 msTTS 2 · Oct 7: 154 msTTS 2 · Oct 8: 151 msTTS 2 · Oct 9: 147 msTTS 2 · Oct 10: 147 msTTS 2 · Oct 11: 148 msTTS 2 · Oct 12: 150 msTTS 2 · Oct 13: 138 msTTS 2 · Oct 14: 164 msTTS 2 · Oct 15: 141 msTTS 2 · Oct 16: 144 ms
Word Error Rate — daily averageDaily average · UTC daysTTS 2's daily Word Error Rate over the last 30 days.
TTS 2 · Sep 23: 5.8%TTS 2 · Sep 24: 3.5%TTS 2 · Sep 25: 2.6%TTS 2 · Sep 26: 3.0%TTS 2 · Sep 27: 3.9%TTS 2 · Sep 28: 0.0%TTS 2 · Sep 30: 0.9%TTS 2 · Oct 1: 4.9%TTS 2 · Oct 2: 4.4%TTS 2 · Oct 3: 4.5%TTS 2 · Oct 4: 6.7%TTS 2 · Oct 5: 3.0%TTS 2 · Oct 6: 4.3%TTS 2 · Oct 7: 4.8%TTS 2 · Oct 8: 5.0%TTS 2 · Oct 9: 3.0%TTS 2 · Oct 10: 1.3%TTS 2 · Oct 11: 3.7%TTS 2 · Oct 12: 5.1%TTS 2 · Oct 13: 3.9%TTS 2 · Oct 14: 7.7%TTS 2 · Oct 15: 5.4%TTS 2 · Oct 16: 4.6%

How fast is TTS 2?

On Inworld AI, TTS 2 measures mean 186 ms time to first audio (10th of 32). Last measured 2026-10-16.

How accurate is TTS 2?

On Inworld AI, TTS 2 measures 1.6% word error rate (9th of 32). Last measured 2026-10-16.

Who hosts TTS 2?

TTS 2 is created by Inworld AI and served by Inworld AI. Coval measures each hosted endpoint separately.

Limits of this comparison

TTS 2 is shown beside TTS 2 Flash without assuming the faster-named variant makes the same tradeoffs.

  • The fixed prompt set does not score character consistency, emotional appropriateness or clone similarity.

Official sources

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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