NVIDIA open-sources Nemotron 3.5 Transcribe, a 30B MoE speech model with about 4B active parameters that handles transcription in 40 languages, speaker attribution and translation, and tops open models on the Open ASR English leaderboard
NVIDIA AI announced Nemotron 3.5 Transcribe on Oct 28, with weights on Hugging Face and ModelScope. It is an offline, instruction-driven speech model whose single checkpoint covers transcription in 40 languages, translation between 31 languages and English, speaker attribution in 13 languages, and audio question answering, on recordings up to an hour long with up to eight labeled speakers. NVIDIA says it ranks first among open-weight models on the Hugging Face Open ASR English leaderboard at 5.33% average WER, and Artificial Analysis measured a 2.8% AA-WER, tied for first among open models with Voxtral Small, which uses 24B active parameters. The weights, the Granary v2 training data and fine-tuning recipes are all released.
Key Takeaways
- Architecture: a speech encoder paired with a Mamba-2/Transformer hybrid MoE language model, about 30B total parameters (34B in the model card counting the audio encoder) and about 4B active per token (4.3B in the model card), shipped in BF16, FP8 and NVFP4
- Capabilities: transcription in 40 languages, translation between 31 languages and English, speaker attribution in 13 languages, audio Q&A (trained in English only) and word-level timestamps, on recordings up to 1 hour with up to 8 speakers
- Official and third-party figures: first among open models on the Open ASR English leaderboard (5.33% average WER), 4.62% mean WER across 7 languages and 10.98% on long-form; Artificial Analysis AA-WER 2.8% and 1.8% on its AA-AgentTalk voice-agent set (next-best open model 2.3%)
- Artificial Analysis measured DeepInfra's hosted endpoint at a 75x speed factor, transcribing a minute of audio in under a second, priced at $2.00 per 1,000 minutes
- Licensed under OpenMDW-1.1 for commercial use; Granary v2 data and NeMo Speech fine-tuning tools are released too, and in NVIDIA's medical case study fine-tuning cut WER a further 45.8% relative to the best prompt
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