Model reference · open weights
supertonic-2 is an open-weight audio or speech model from Supertone.
For self-hosting, compare this build's requirements below with the GPU you plan to rent.
Summary of the Supertone/supertonic-2 model card, 2026-10-01
What it is
| Released by | Supertone |
|---|---|
| Released | 2026-01-06 |
From the model card
Supertonic is a lightning-fast, on-device text-to-speech system designed for extreme performance with minimal computational overhead. Powered by ONNX Runtime, it runs entirely on your device—no cloud, no API calls, no privacy concerns.
Supertonic 2 extends multilingual capabilities while maintaining the same inference speed and efficiency as the original.
| Language | Code |
|---|---|
| English | en |
| Korean | ko |
| Spanish | es |
| Portuguese | pt |
| French | fr |
We evaluated Supertonic's performance (with 2 inference steps) using two key metrics across input texts of varying lengths: Short (59 chars), Mid (152 chars), and Long (266 chars).
Metrics:
| System | Short (59 chars) | Mid (152 chars) | Long (266 chars) |
|---|---|---|---|
| Supertonic (M4 pro - CPU) | 912 | 1048 | 1263 |
| Supertonic (M4 pro - WebGPU) | 996 | 1801 | 2509 |
| Supertonic (RTX4090) | 2615 | 6548 | 12164 |
API ElevenLabs Flash v2.5 | 144 | 209 | 287 |
API OpenAI TTS-1 | 37 | 55 | 82 |
API Gemini 2.5 Flash TTS | 12 | 18 | 24 |
API Supertone Sona speech 1 | 38 | 64 | 92 |
Open Kokoro | 104 | 107 | 117 |
Open NeuTTS Air | 37 | 42 | 47 |
Notes:
API= Cloud-based API services (measured from Seoul)Open= Open-source models Supertonic (M4 pro - CPU) and (M4 pro - WebGPU): Tested with ONNX Supertonic (RTX4090): Tested with PyTorch model Kokoro: Tested on M4 Pro CPU with ONNX NeuTTS Air: Tested on M4 Pro CPU with Q8-GGUF
| System | Short (59 chars) | Mid (152 chars) | Long (266 chars) |
|---|---|---|---|
| Supertonic (M4 pro - CPU) | 0.015 | 0.013 | 0.012 |
| Supertonic (M4 pro - WebGPU) | 0.014 | 0.007 | 0.006 |
| Supertonic (RTX4090) | 0.005 | 0.002 | 0.001 |
API ElevenLabs Flash v2.5 | 0.133 | 0.077 | 0.057 |
API OpenAI TTS-1 | 0.471 | 0.302 | 0.201 |
API Gemini 2.5 Flash TTS | 1.060 | 0.673 | 0.541 |
API Supertone Sona speech 1 | 0.372 | 0.206 | 0.163 |
Open Kokoro | 0.144 | 0.124 | 0.126 |
Open NeuTTS Air | 0.390 | 0.338 | 0.343 |
Characters per Second (5-step)
| System | Short (59 chars) | Mid (152 chars) | Long (266 chars) |
|---|---|---|---|
| Supertonic (M4 pro - CPU) | 596 | 691 | 850 |
| Supertonic (M4 pro - WebGPU) | 570 | 1118 | 1546 |
| Supertonic (RTX4090) | 1286 | 3757 | 6242 |
Real-time Factor (5-step)
| System | Short (59 chars) | Mid (152 chars) | Long (266 chars) |
|---|---|---|---|
| Supertonic (M4 pro - CPU) | 0.023 | 0.019 | 0.018 |
| Supertonic (M4 pro - WebGPU) | 0.024 | 0.012 | 0.010 |
| Supertonic (RTX4090) | 0.011 | 0.004 | 0.002 |
This project’s sample code is released under the MIT License. - see the LICENSE for details.
The accompanying model is released under the OpenRAIL-M License. - see the LICENSE file for details.
This model was trained using PyTorch, which is licensed under the BSD 3-Clause License but is not redistributed with this project. - see the LICENSE for details.
Copyright (c) 2026 Supertone Inc.
Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.
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