NVIDIA Releases Audex (Nemotron-Labs-Audex-30B-A3B): A Unified Audio-Text LLM That Preserves the Text Intelligence of Its Backbone
NVIDIA has launched Audex (Nemotron-Labs-Audex-30B-A3B), a unified audio-text giant language mannequin. It understands and generates each audio and speech. It additionally retains the textual content intelligence of its spine. The checkpoints, together with a smaller Audex-2B, are launched underneath a noncommercial license.
Most multimodal fashions pay a textual content tax. When labs add audio or imaginative and prescient output, textual content benchmarks typically drop. NVIDIA analysis group reviews this even for speech-only output fashions. Audex is designed to keep away from that regression.
TL;DR
- Audex is a single 30B-A3B MoE mannequin that handles audio out and in.
- Audio inputs enter the textual content embedding house; audio outputs are handled like textual content tokens.
- Text scores match the spine, with small beneficial properties and small losses per benchmark.
- Multi-stage SFT plus text-only Cascade RL avoids the ordinary multimodal textual content regression.
- It is few of the open fashions that generate common audio past speech.
What is Audex?
Audex is a single Mixture-of-Experts (MoE) Transformer decoder. It has 30B complete parameters and 3B activated per token. The spine is Nemotron-Cascade-2-30B-A3B, a text-only MoE LLM. That spine is a hybrid Mamba-Transformer with 52 layers. It makes use of 128 routable specialists and 6 activated specialists.
The design is intentionally easy. Audio inputs are encoded and projected into the textual content embedding house. Text tokens and quantized audio tokens are then handled uniformly throughout technology. There is not any thinker-talker cut up and no stacked cascade of fashions.
Because the design stays easy, Audex runs on commonplace LLM stacks. These embrace Megatron-LM for coaching and vLLM for inference. It helps each an instruct mode and a pondering mode. Context size reaches 1M tokens.
How the Unified Design Works
Three elements sit round the LLM spine:
- An audio encoder reads sound. Audex makes use of AF-Whisper from Audio Flamingo 3. It shares the Whisper Large-v3 structure and handles 16kHz enter.
- Two-layer MLP adapters map audio options into the mannequin dimension.
- An prolonged vocabulary holds discrete audio output tokens. The unique 131,072 tokens develop to 205,312.
Audex makes use of two codecs for output. Speech makes use of X-Codec2 at 50 tokens per second. It applies single-layer finite scalar quantization (FSQ) with a 65,536 codebook.
Non-speech sound makes use of X-Codec at 200 tokens per second. It makes use of 4 flattened residual vector quantization (RVQ) layers. Complex sound will get a bigger token finances than speech. The interactive demo under computes these token counts for any period.
Training
Audex wants no audio pretraining. It begins from the text-only SFT checkpoint. Training then provides capabilities stage by stage.
The multi-stage SFT curriculum runs so as: textual content SFT, audio warmup, audio technology, then audio understanding. During audio warmup, textual content token embeddings keep frozen. Unfreezing them degraded textual content high quality in ablations.
NVIDIA analysis group additionally examined a single-stage recipe that mixes all knowledge directly. That recipe broke long-context retrieval on NIAH. Multi-stage coaching averted this, so it turned the default.
After SFT, the analysis group applies text-only Cascade RL and multi-domain on-policy distillation (MOPD). Audio duties present marginal or no regression after this text-only RL. Text scores enhance at the identical time.
The knowledge combine is giant. It combines 157.4B audio tokens and 320.5B textual content tokens. Tasks span ASR, AST, TTS, text-to-audio, and audio understanding.
Benchmark and Performance
On textual content, Audex tracks its spine intently. It scores 86.4 on MMLU-Redux towards the spine’s 86.3. It even leads on IMO AnswerBench, 81.1 versus 79.3. Small drops seem on MMLU-Pro and GPQA-Diamond.
Audex additionally tops the text-only Qwen3.5-35B-A3B on a number of reasoning, alignment, and instruction-following benchmarks. The comparably sized Qwen3-Omni-30B-A3B-Thinking exhibits giant reasoning drops versus its personal spine.
| Benchmark | Audex 30B-A3B | Qwen3.5-35B-A3B | Qwen3-Omni-30B-A3B-Thinking |
|---|---|---|---|
| HMMT Feb25 | 92.2 | 89.0 | 60.4 |
| IMO AnswerBench | 81.1 | 74.8 | 59.9 |
| DwellCodeBench v6 | 85.3 | 74.6 | 59.2 |
| ArenaHard v2 | 81.6 | 65.4 | 55.1 |
| IFBench (immediate) | 77.8 | 70.2 | 52.4 |
On speech recognition, Audex leads these open fashions. It data 6.82 common phrase error price on the OpenASR leaderboard. That beats Step-Audio-R1.1-33B and Qwen3-Omni-30B-A3B-Thinking.
On audio understanding the image is combined. Audex leads open fashions on MMAU. It exhibits gaps on MMAR and MMSU versus the strongest audio LLMs. Audex additionally generates common audio, which the different main open fashions can not.
| Audio benchmark | Audex 30B-A3B | Step-Audio-R1.1-33B | Qwen3-Omni-30B-A3B-Thinking |
|---|---|---|---|
| MMAU | 75.6 | 73.6 | 75.4 |
| MMAR | 63.2 | 69.8 | 66.4 |
| MMSU | 63.4 | 74.1 | 70.2 |
| Audio Entailment | 95.0 | 61.6 | 61.6 |
| OpenASR (WER, decrease is best) | 6.82 | 7.91 | 8.00 |
| BigBenchAudio | 90.0 | 97.6 | not reported |
Audex leads on MMAU, Audio Entailment, and OpenASR phrase error price. It trails these open baselines on MMAR, MMSU, and BigBenchAudio.
Use Cases with Examples
- Consider a multilingual name middle. Audex can transcribe a German name and translate it to English. Its speech translation output lists the supply language, transcript, then English translation.
- Consider accessibility tooling. A developer can add fixed-voice text-to-speech to a studying app. The Seed-TTS-Eval English phrase error price is a low 1.70.
- Consider sound design or prototyping. A caption like “birds chirping in a forest” yields a 10-second clip. General audio technology makes use of an enhancement VAE for 48kHz output.
- Consider a voice assistant. Speech-to-speech runs as a cascade, however one checkpoint serves each step. Audex scores 90.0 on BigBenchAudio.
Quick Start Example
Audex follows the ChatML template. The reference container is vLLM 0.20.0. Audio enter decoding wants the audio extras.
Audio understanding, ASR, and translation share one audio question-answering format. The <sound> placeholder marks the place the audio goes.
[
{
"id": "sample_0",
"sound": "/path/to/audio_0.wav",
"conversations": [
{"from": "human", "value": "<sound>nDescribe the audio in detail."},
{"from": "gpt", "value": "N/A"}
]
}
]
The mannequin card ships a vLLM audio-QA script for this enter format.
# add audio codecs, then run audio QA offline
python3 -m pip set up "vllm"
python inference_scripts_vllm/audioqa_scripts/run_audioqa_vllm.py
--model-path "$(pwd)/checkpoint_folder_full"
--input-json ./inputs.json
--output-jsonl ./outcomes.jsonl
--tensor-parallel-size 8
For audio understanding, the analysis group recommends top_p=0.9 and temperature=0.7. For recognition and translation, use grasping sampling. Generation duties want classifier-free steering, proven in the demo’s recipe tab.
Strengths and Weaknesses
Strengths
- Marginal or no textual content regression versus its text-only spine.
- Single unified mannequin, suitable with Megatron-LM and vLLM.
- Among the strongest open fashions, solely Audex generates common audio.
- Leads Qwen3.5-35B-A3B on a number of reasoning and alignment duties.
Weaknesses
- The NVIDIA OneMeans Noncommercial License limits industrial use.
- Audio understanding exhibits gaps on MMAR and MMSU versus high audio LLMs.
- Speech-to-speech is cascaded, not native full-duplex.
- Reinforcement studying is text-only; audio-text RL is future work.
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The publish NVIDIA Releases Audex (Nemotron-Labs-Audex-30B-A3B): A Unified Audio-Text LLM That Preserves the Text Intelligence of Its Backbone appeared first on MarkTechPost.
