---
language:
  - en
license: cc-by-nc-4.0
tags:
  - speech-to-speech
  - full-duplex
  - mlx
  - apple-silicon
  - personaplex
  - moshi
base_model: nvidia/personaplex-7b-v1
pipeline_tag: audio-to-audio
---


> **Note**: For full-duplex (real-time) inference, use the [8-bit variant](https://huggingface.co/aufklarer/PersonaPlex-7B-MLX-8bit) instead. 4-bit quantization degrades PersonaPlex response quality significantly — INT8 is both 30% faster (112ms vs 158ms/step) and produces coherent responses where INT4 generates garbled output.


# PersonaPlex-7B MLX 4-bit

[PersonaPlex](https://arxiv.org/abs/2504.07966) 7B full-duplex speech-to-speech model converted to MLX safetensors with 4-bit quantization for Apple Silicon.

Converted from [nvidia/personaplex-7b-v1](https://huggingface.co/nvidia/personaplex-7b-v1) (based on [Kyutai Moshi](https://kyutai.org/moshi/) architecture).

**Swift inference**: [soniqo/speech-swift](https://github.com/soniqo/speech-swift)

**Library Docs**: [soniqo.audio](https://soniqo.audio)

**Blog**: [PersonaPlex on Apple Silicon — Full-Duplex Speech-to-Speech in Native Swift with MLX](https://blog.ivan.digital/nvidia-personaplex-7b-on-apple-silicon-full-duplex-speech-to-speech-in-native-swift-with-mlx-0aa5276f2e23)

## Model Details

| Component | Architecture | Size |
|-----------|-------------|------|
| Temporal Transformer | 32-layer, 4096d, 32 heads (7B params) | ~3.5 GB (4-bit) |
| Depformer | 6-layer, 1024d, 16 heads, per-codebook weights | ~50 MB (fp16) |
| Mimi Codec | SEANet encoder/decoder + 8L transformer + 16 RVQ codebooks | ~370 MB (fp16) |
| Embeddings | Text + 16 audio embeddings + output heads | ~940 MB (fp16) |
| **Total** | | **~4.9 GB** |

## Architecture

```
[User Audio 24kHz] → [Mimi Encoder] → 16 codebook tokens @ 12.5Hz
                                              ↓
              [Temporal Transformer: 32L, dim=4096, 7B params]
                  17 streams: text + 8 user audio + 8 agent audio
                                              ↓
              [Depformer: 6L, dim=1024, per-codebook weights]
                  16 sequential steps → agent audio codebook tokens
                                              ↓
[Agent Audio 24kHz] ← [Mimi Decoder] ← codebook tokens @ 12.5Hz
```

## Voices

18 voice presets available:

| Category | Voices |
|----------|--------|
| Natural Female | NATF0, NATF1, NATF2, NATF3 |
| Natural Male | NATM0, NATM1, NATM2, NATM3 |
| Variety Female | VARF0, VARF1, VARF2, VARF3, VARF4 |
| Variety Male | VARM0, VARM1, VARM2, VARM3, VARM4 |

## Files

- `temporal.safetensors` — Temporal transformer (4-bit quantized, group_size=64)
- `depformer.safetensors` — Depformer layers + input projections (fp16)
- `embeddings.safetensors` — Text/audio embeddings + output heads (fp16)
- `mimi.safetensors` — Mimi neural audio codec (fp16)
- `voices/*.safetensors` — Voice preset embeddings
- `tokenizer_spm_32k_3.model` — SentencePiece tokenizer
- `config.json` — Model configuration

## Quantization

- Temporal transformer attention (Q/K/V output projections) and FFN: 4-bit with group_size=64
- Attention input projection (`in_proj`): kept fp16 (packed Q+K+V format)
- Depformer: kept fp16 (~50 MB, not worth quantizing)
- Mimi codec: kept fp16 (audio quality sensitive)

## Usage

```swift
import PersonaPlex

let model = try await PersonaPlexModel.fromPretrained()
let response = model.respond(
    userAudio: audioSamples,  // [Float] 24kHz mono
    voice: .NATM0,
    maxSteps: 500
)
```

### CLI

```bash
swift run personaplex-cli --input question.wav --output response.wav --voice NATM0
```

See [soniqo/speech-swift](https://github.com/soniqo/speech-swift) for build instructions.

## License

CC-BY-NC-4.0 (same as upstream PersonaPlex)

## Citation

```bibtex
@article{nguyen2025personaplex,
  title={PersonaPlex: Enhancing Human-Centric AI Through Full-Duplex Multi-Turn Conversations With Persona-Conditioned Voice Responses},
  author={Nguyen, Tu Anh and others},
  journal={arXiv preprint arXiv:2504.07966},
  year={2025}
}
```

---

- **Guide**: [soniqo.audio/guides/respond](https://soniqo.audio/guides/respond)
- **Docs**: [soniqo.audio](https://soniqo.audio)
- **GitHub**: [soniqo/speech-swift](https://github.com/soniqo/speech-swift)