Voice AI BenchmarksBy

PROVIDERLAST 30 DAYS

official resource

Gradium voice AI models and benchmarks

Gradium lists 2 STT and TTS models in Coval. Fastest dated mean latency over 30 days: STT: Default at 258 ms TTFS, with 8.8% WER. TTS: Default at 63 ms TTFA, with 1.9% WER. Coval benchmarks hosted endpoints daily using a consistent evaluation methodology. Last measured .

Gradium provides real-time speech recognition and synthesis APIs.

Measured models
2
STTTTS
Best STT model#19 / 29
258ms
Default
Best TTS model#2 / 32
63ms
Default

Overview

Gradium builds and serves both its recognition and synthesis endpoints in-house.

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
Default
Text-to-Speech
Default

Speech-to-Text

Full STT dashboard

Ranked on Time to Final Segment against 29 measured models.

Time to Final Segmentms · lower is better · Gradium models markedEvery measured STT model on Time to Final Segment, with Gradium's models highlighted.
  1. #1Qwen3 ASR 1.7b39 ms
  2. #2STT RT v545 ms
  3. #3Qwen3 ASR Fast47 ms
  4. #4STT 166 ms
  5. #5Nova 385 ms
  6. #6Nova 287 ms
  7. #7Parakeet TDT 0.6B v397 ms
  8. #19Default258 ms
leaders plus Gradium models · 21 other models in the full table
Word Error Rate% · lower is better · Gradium models markedEvery measured STT model on Word Error Rate, with Gradium'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. #29Default8.8%
leaders plus Gradium models · 23 other models in the full table
Time to First Tokenms · lower is better · Gradium models markedEvery measured STT model on Time to First Token, with Gradium'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 11212 ms
  8. #23Default1986 ms
leaders plus Gradium models · 19 other models in the full table
TTFS vs WER — Gradium vs every measured modelEach point is one measured STT model · Gradium models highlighted · 30-day averagesTime to Final Segment against Word Error Rate for every measured STT model, with Gradium's models highlighted.
Qwen3 ASR 1.7b — 39 ms, 2.9%STT RT v5 — 45 ms, 4.8%Qwen3 ASR Fast — 47 ms, 2.6%STT 1 — 66 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 — 99 ms, 5.8%Scribe v2 Realtime — 122 ms, 4.4%Whisper Large v3 via Baseten — 131 ms, 4.5%Universal 3.6 Pro — 135 ms, 2.1%Ink 2 — 148 ms, 3.6%Universal 3.5 Pro — 168 ms, 2.4%Whisper Large v3 via Together AI — 200 ms, 7.4%Pulse — 205 ms, 4.6%Grok STT — 223 ms, 4.1%resonant-1 — 252 ms, 2.6%Linden 1 — 271 ms, 3.9%Gemini 3.5 Transcribe Live — 317 ms, 3.0%Daytona STT — 399 ms, 4.9%Voxtral Mini Transcribe Realtime 2602 — 410 ms, 5.4%GPT Realtime Whisper — 599 ms, 4.0%Solaria 1 — 636 ms, 6.0%GPT-4o mini Transcribe — 708 ms, 3.9%Chirp 3 — 768 ms, 3.2%GPT-4o Transcribe — 783 ms, 3.8%Chirp 2 — 908 ms, 3.9%Default — 258 ms, 8.8%
Benchmarked models with their Time to Final Segment over the last 30 days.
ModelHostTTFSRank
DefaultGradium258 ms19th 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 · Gradium models markedEvery measured TTS model on Time to First Audio, with Gradium's models highlighted.
  1. #1vui60 ms
  2. #2Default63 ms
  3. #3Qwen3 TTS Fast68 ms
  4. #4TTS Flash 292 ms
  5. #5Qwen3 TTS 1.7b107 ms
  6. #6Simba 3.0111 ms
  7. #7Palabra TTS v1119 ms
leaders plus Gradium models · 25 other models in the full table
Word Error Rate% · lower is better · Gradium models markedEvery measured TTS model on Word Error Rate, with Gradium's models highlighted.
  1. #1Sonic 3.61.5%
  2. #2Simba 3.01.5%
  3. #3S2.1 Pro Free1.5%
  4. #4Chirp 3 HD1.5%
  5. #5S2.1 Pro1.5%
  6. #6Lightning v3.1 Pro1.5%
  7. #7Sonic 3.51.5%
  8. #22Default1.9%
leaders plus Gradium models · 24 other models in the full table
TTFA vs WER — Gradium vs every measured modelEach point is one measured TTS model · Gradium models highlighted · 30-day averagesTime to First Audio against Word Error Rate for every measured TTS model, with Gradium's models highlighted.
vui — 60 ms, 2.1%Qwen3 TTS Fast — 68 ms, 1.8%TTS Flash 2 — 92 ms, 1.6%Qwen3 TTS 1.7b — 107 ms, 1.8%Simba 3.0 — 111 ms, 1.5%Palabra TTS v1 — 119 ms, 2.6%Simba 3.2 — 126 ms, 1.9%drama3-preview — 160 ms, 2.1%Flash v2.5 — 191 ms, 1.8%TTS 2 — 192 ms, 1.6%Eleven v4 Turbo — 201 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%Sonic 3.5 — 293 ms, 1.5%Phantom Z 3.4 conversational — 296 ms, 1.8%Aura 2 — 297 ms, 1.8%Sonic 3.6 — 299 ms, 1.5%Falcon 2 — 303 ms, 1.7%Coda — 332 ms, 9.5%S2.1 Pro — 341 ms, 1.5%Grok TTS — 362 ms, 1.6%S1 — 389 ms, 1.8%Lightning v3.1 Pro — 392 ms, 1.5%Daytona TTS — 486 ms, 1.6%Aura 2 En — 572 ms, 2.0%Chirp 3 HD — 598 ms, 1.5%Qwen3 TTS Flash Realtime — 718 ms, 3.0%S2.1 Pro Free — 850 ms, 1.5%GPT-4o mini TTS — 2584 ms, 1.8%Default — 63 ms, 1.9%
Benchmarked models with their Time to First Audio over the last 30 days.
ModelHostTTFARank
DefaultGradium63 ms2nd of 32

How fast are Gradium's STT and TTS models?

Default measures mean 258 ms time to final segment (19th of 29) among STT systems. Last measured 2026-10-14. Default measures mean 63 ms time to first audio (2nd of 32) among TTS systems. Last measured 2026-10-14.

How accurate are Gradium's STT and TTS models?

Default measures 8.8% word error rate (29th of 31) among STT systems. Last measured 2026-10-14. Default measures 1.9% word error rate (22nd of 32) among TTS systems. Last measured 2026-10-14.

Which Gradium model is fastest?

Its fastest dated STT result is Default at mean 258 ms time to final segment (19th of 29) among STT systems, with 8.8% WER. Last measured 2026-10-14. Its fastest dated TTS result is Default at mean 63 ms time to first audio (2nd of 32) among TTS systems, with 1.9% WER. Last measured 2026-10-14.

Limits of this comparison

Coval measures its default STT and TTS configurations separately.

  • The API name `default` is also used by other providers, so Gradium's default configurations are identified by provider and category.

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.

Book a Demo