AssemblyAI-TTS-1 benchmarks: top speed, mid-tier accuracy
Artificial Analysis ran multiple benchmark tests on AssemblyAI's first speech synthesis model, AssemblyAI-TTS-1, painting an overall picture of "top-tier speed, mediocre details."
Confirmed
- Speed: 162 characters per second, ranking first on the TTS speed leaderboard, ahead of Cartesia Sonic (148.6), Mistral Voxtral, and others.
- Pricing: $15 per million characters, placing it in the top tier.
- Pronunciation robustness: An overall score of 81.7%, ranking 16th. This benchmark uses human reviewers to judge whether models correctly read four categories of difficult text; expanding abbreviations is a clear weak spot for AssemblyAI-TTS-1.
- Controlled Voice Arena: With all models using the same cloned voice, AssemblyAI-TTS-1 ranks 10th with an Elo of 1110—6th in the knowledge-sharing category at 1139, and 10th in both the assistant and customer service categories.
- The company also released a sample audio clip of typical customer service dialogue (covering cancellation fees and waivers) for a direct listen to its naturalness.
Why It Matters
AssemblyAI's first foray into speech synthesis lands in the top tier on speed and pricing, signaling that competition in the TTS market is shifting from pure naturalness toward latency and cost. However, its 16th-place pronunciation robustness suggests it still needs improvement on real-world customer service text like abbreviations and proper nouns—so model selection requires weighing speed against accuracy.
2026-10-29 ~ 2026-10-29 · 6 related posts
- Episode 1: AssemblyAI Launches Its First TTS Model, TTS-1(2026-10-28, 5 posts)
- Episode 2: AssemblyAI-TTS-1 benchmarks: top speed, mid-tier accuracy(2026-10-29, 6 posts)
Primary sources
- AssemblyAI-TTS-1 hits 162 chars/sec, fastest among major TTS models at $15/1M characters — ArtificialAnlys ·
- Independent TTS benchmark of 27 models: AssemblyAI tops phone numbers and codes — AssemblyAI ·
- AssemblyAI-TTS-1 scores 81.7% on pronunciation robustness, shorthand expansion is its weak spot — ArtificialAnlys ·
- AssemblyAI-TTS-1 ranks #10 at Elo 1110 in Controlled Voice Arena, #6 for knowledge sharing — ArtificialAnlys · 2026-10-29
- [source] AssemblyAI-TTS-1 scores 81.7% on pronunciation robustness, shorthand expansion is its weak spot — ArtificialAnlys · 2026-10-29
- Sample clip of AssemblyAI-TTS-1 reading a customer-service script released — ArtificialAnlys · 2026-10-29
- [source] AssemblyAI-TTS-1 hits 162 chars/sec, fastest among major TTS models at $15/1M characters — ArtificialAnlys · 2026-10-29
- AssemblyAI-TTS-1 tops TTS speed at 162 chars/sec as Artificial Analysis refreshes leaderboards — ArtificialAnlys · 2026-10-29
- [source] Independent TTS benchmark of 27 models: AssemblyAI tops phone numbers and codes — AssemblyAI · 2026-10-29