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Model reference · open weights

supertonic

Available as managed deployment Audio Supertone Text→speech 1 variants 1k dl/mo

supertonic is an open-weight audio or speech model from Supertone. AxForge deploys and operates it for you on dedicated EU-owned hardware — with the licence handled where one is required.

Request deployment All audio & music

Available as managed deployment — configured and operated for you on dedicated EU hardware, quoted per deployment.

What it is

Released bySupertone
TypeAudio & music
TaskText→speech
Runs withsupertonic
Released2025-11-18
Popularity1k downloads / month
LicenceOpen weights

About

What supertonic is

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.

🎧 Try it now: Experience Supertonic in your browser with our Interactive Demo, or Hugging Face app or get started with pre-trained models from Hugging Face Hub

🛠 GitHub Repository To use Supertonic most easily, visit the official GitHub repository: https://github.com/supertone-inc/supertonic You’ll find multi-language example codes.

Read the full model card

Table of Contents

Why Supertonic?

  • ⚡ Blazingly Fast: Generates speech up to 167× faster than real-time on consumer hardware (M4 Pro)—unmatched by any other TTS system
  • 🪶 Ultra Lightweight: Only 66M parameters, optimized for efficient on-device performance with minimal footprint
  • 📱 On-Device Capable: Complete privacy and zero latency—all processing happens locally on your device
  • 🎨 Natural Text Handling: Seamlessly processes numbers, dates, currency, abbreviations, and complex expressions without pre-processing
  • ⚙️ Highly Configurable: Adjust inference steps, batch processing, and other parameters to match your specific needs
  • 🧩 Flexible Deployment: Deploy seamlessly across servers, browsers, and edge devices with multiple runtime backends.

Language Support

We provide ready-to-use TTS inference examples across multiple ecosystems:

Language/PlatformPathDescription
[Python]py/ONNX Runtime inference
[Node.js]nodejs/Server-side JavaScript
[Browser]web/WebGPU/WASM inference
[Java]java/Cross-platform JVM
[C++]cpp/High-performance C++
[C#]csharp/.NET ecosystem
[Go]go/Go implementation
[Swift]swift/macOS applications
[iOS]ios/Native iOS apps
[Rust]rust/Memory-safe systems
[Flutter]flutter/Cross-platform apps

For detailed usage instructions, please refer to the README.md in each language directory.

Getting Started

First, clone the repository:

git clone https://github.com/supertone-inc/supertonic.git
cd supertonic

Prerequisites

Before running the examples, download the ONNX models and preset voices, and place them in the assets directory:

git clone https://huggingface.co/Supertone/supertonic assets

Note: The Hugging Face repository uses Git LFS. Please ensure Git LFS is installed and initialized before cloning or pulling large model files.

  • macOS: brew install git-lfs && git lfs install
  • Generic: see https://git-lfs.com for installers

Technical Details

  • Runtime: ONNX Runtime for cross-platform inference (CPU-optimized; GPU mode is not tested)
  • Browser Support: onnxruntime-web for client-side inference
  • Batch Processing: Supports batch inference for improved throughput
  • Audio Output: Outputs 16-bit WAV files

Performance

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:

  • Characters per Second: Measures throughput by dividing the number of input characters by the time required to generate audio. Higher is better.
  • Real-time Factor (RTF): Measures the time taken to synthesize audio relative to its duration. Lower is better (e.g., RTF of 0.1 means it takes 0.1 seconds to generate one second of audio).

Characters per Second

SystemShort (59 chars)Mid (152 chars)Long (266 chars)
Supertonic (M4 pro - CPU)91210481263
Supertonic (M4 pro - WebGPU)99618012509
Supertonic (RTX4090)2615654812164
API ElevenLabs Flash v2.5144209287
API OpenAI TTS-1375582
API Gemini 2.5 Flash TTS121824
API Supertone Sona speech 1386492
Open Kokoro104107117
Open NeuTTS Air374247

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

Real-time Factor

SystemShort (59 chars)Mid (152 chars)Long (266 chars)
Supertonic (M4 pro - CPU)0.0150.0130.012
Supertonic (M4 pro - WebGPU)0.0140.0070.006
Supertonic (RTX4090)0.0050.0020.001
API ElevenLabs Flash v2.50.1330.0770.057
API OpenAI TTS-10.4710.3020.201
API Gemini 2.5 Flash TTS1.0600.6730.541
API [Supertone Sona speech 1](https://docs.supertoneapi.com/en/a

From the published model card. Full card on the HuggingFace links in the sidebar.

How it works

How audio & music work

Audio or textinputAudio modelrecognise / synthesiseText or audiooutputSpeech-to-text turns audio into text; text-to-speech and music models turn text into audio.

Using it via the API

Call it like any OpenAI endpoint

Once AxForge deploys supertonic for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (supertonic below is illustrative; you get the exact model name on deployment.)

$ curl -sS https://api.axforge.ai/v1/audio/transcriptions \
  -H "Authorization: Bearer $AXFORGE_API_KEY" \
  -F model="supertonic" -F file=@audio.mp3

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