Open TTS Leaderboard separates streaming speed from voice-quality measures

In a September 30, 2026 post, the authors introduced the Open TTS Leaderboard as an objective-metrics complement to human-vote rankings, not a replacement for human preference. For interactive use, its Streaming tab ranks models by time-to-first-audio, while RTFx measures batched offline inference. The streaming test runs one audio at a time across 50 English CV3-Eval prompts, uses default voices and reports median TTFA after excluding the first 3 warm-up runs. Results are shown for an H200 GPU, with CPU results available for a small, growing set of models.

The leaderboard reports word or character error rates for intelligibility and speaker-embedding cosine similarity for voice identity. Its authors say those metrics do not directly measure naturalness, expressiveness or listener preference. Users can compare generated samples in the Listen tab and submit feedback.