Phonon by Gradium

Gradium

3 min read Original article ↗

Introducing

Phonon

Gradium's open-weight text-to-speech, small enough to ship in any app. Private, and it works offline.

Already trusted by

1.7%

Word Error Rate (WER)

Phonon 31m · English Tested on 500 sentences that other models get wrong: phone numbers, email addresses, postal codes.

Read the blog post

1.70%

Phonon 31m

2.11%

Phonon 40m multilingual

2.22%

Phonon 40m

3.50%

Kokoro

7.40%

Kitten TTS

8.71%

NeuTTS Nano

Phonon 1.0

Three models,
One for every device.

Languages

English

English, French, German, Spanish, Portuguese, one model per language

English, French, German, Spanish, Portuguese in a single model

Where it runs

One model,
All of your hardware.

  • Any processor

    Laptops, desktops, Android phones, even a Raspberry Pi 5. No graphics card needed.

  • iPhone, iPad and Mac

    On Apple's own AI chip, through a Swift package. Up to 22× faster than real time on an iPhone 16 Pro.

  • In a web page

    Runs in the visitor's browser, so their text never leaves their device. The demo at the top of this page is it.

  • On a graphics card

    When there is one, for the fastest speech: NVIDIA, Apple, Vulkan or WebGPU, chosen when you build it.

Compatible with

Set up Phonon, Gradium's on-device text-to-speech, from https://github.com/gradium-ai/xn-ptts.

Read the README first and follow it over anything you assume.

1. Install the Rust CLI from the repository root with
   cargo install --path ptts --locked --features cli.
2. Point MODEL_DIR at the model folder (config.json, model.q8.gguf,
   tokenizer.json and the voices).
3. Synthesize "Hello world" with --lang en --quant q8 --voice Freya
   to out.wav.

Verify the file plays and tell me how to change the voice.

Text in, a WAV out. The fastest way to hear it.

Questions?We’re here to help

[ 4 ]

Start
Building

[ 1 ] Creazione di Adamo, by Michelangelo Buonarroti. Date: c. 1511, part of the ceiling painted 1508-1512. Material: fresco. Dimensions: 280 × 570 cm. Current location: Cappella Sistina, volta, Musei Vaticani, Vatican City.

[ 2 ] Les trois Grâces. Artist: unknown; Roman, with restorations by Nicolas Cordier and Amainci, 1609. Date: 2nd century AD (?). Material: marble, probably Greek. Dimensions: h. 123 cm, w. 86 cm, d. 29 cm. Current location: Musée du Louvre, Aile Sully, Salle 348, Paris. Inventory number: Ma 287; MR 211; N 642.

[ 3 ] Victoire de Samothrace. Artist: unknown, Rhodes (?). Date: c. 200-175 BC. Material: Parian marble for the figure, grey Lartos marble for the ship. Dimensions: h. 328 cm overall. Current location: Musée du Louvre, Aile Denon, Escalier Daru, Salle 703, Paris. Inventory number: Ma 2369; NIII 2447; MNB 2118; MNC 1433.

[ 4 ] Portrait de Juliette Récamier, née Bernard (1777-1849), by Jacques-Louis David. Date: 1800. Material: oil on canvas. Dimensions: h. 174 cm, w. 244 cm. Current location: Musée du Louvre, Aile Denon, Salle 702, Salle Daru, néoclassicisme, Paris. Inventory number: INV 3708; C 124.