{
  "publisher": "Coval",
  "board": "https://benchmarks.coval.ai/tts",
  "harness": "https://github.com/coval-ai/benchmarks",
  "methodology": "https://github.com/coval-ai/benchmarks/blob/main/docs/methodology.md",
  "provenance": "SpeechifyAI's reading of Coval's public results API, the per-request rows behind benchmarks.coval.ai, produced by Coval's open-source harness. SUCCEEDED runs only. The daily medians for 13 to 20 September were read on 20 Sep 2026 at 18:34 UTC, before the API's rolling retention dropped them; the 24-hour window was read from /v2/results on 24 Sep 2026 and ends at 19:02 UTC.",
  "metric": "TTFA = (first audio chunk arrival - synthesis start) + leading silence inside the stream before the first audible sample, in milliseconds, as Coval's methodology defines it. Leading silence is Coval's TTFALeadingSilence, found by an RMS-threshold onset detector on the assembled audio.",
  "capturedOn": "2026-09-24",
  "date": "24 Sep 2026",
  "notes": "No runs were recorded for 15 to 17 September. Medians of the parts are read separately, so a day's TTFA median minus its leading-silence median is not a separately measured round trip.",
  "daily": [
    { "day": "2026-09-13", "label": "13 Sep", "simba32Ttfa": 379, "simba30Ttfa": 469, "simba32LeadingSilence": 21 },
    { "day": "2026-09-14", "label": "14 Sep", "simba32Ttfa": 368, "simba30Ttfa": 446, "simba32LeadingSilence": 102 },
    { "day": "2026-09-18", "label": "18 Sep", "simba32Ttfa": 116, "simba30Ttfa": 100, "simba32LeadingSilence": 10 },
    { "day": "2026-09-19", "label": "19 Sep", "simba32Ttfa": 122, "simba30Ttfa": 106, "simba32LeadingSilence": 13 },
    { "day": "2026-09-20", "label": "20 Sep", "simba32Ttfa": 107, "simba30Ttfa": 120, "simba32LeadingSilence": 13 }
  ],
  "window24h": {
    "end": "2026-09-24T19:02:13Z",
    "label": "24 h to 24 Sep",
    "simba32": { "medianTtfa": 106.3, "runs": 150 },
    "simba30": { "medianTtfa": 102.2, "runs": 152 }
  }
}