Neuphonic · Voice

NeuTTS 2E

Commercial use: conditions applyNeuTTS Open License v1.0

audio.cpp's conversion table labels this package Apache-2.0. The upstream Neuphonic repository ships a custom licence, the NeuTTS Open License v1.0, that caps commercial use at $5M annual revenue and gates the download of the original weights. Where a converter's label and the rights-holder's licence file disagree, this page follows the rights-holder, so the cap is shown.

neuphonic/neutts-2e on Hugging Face audio.cpp

The licence

Summarized from the linked source documents, last checked 25 August 2026. Every claim links to its source; anything unconfirmed is marked unconfirmed.

NeuTTS Open License v1.0

Commercial use: conditions apply

Commercial use is permitted below the licence's Threshold, defined as USD $5,000,000 in annual revenue; a legal entity above it needs a commercial licence from Neuphonic. Non-profits are exempt for research and non-commercial purposes.

Conditions

The licence states that commercial use "by a Legal Entity that exceeds the Threshold is not licensed", with the Threshold set at USD $5,000,000 annual revenue.
The original upstream weights are gated: you accept conditions and share contact details to get the files. Soundbox downloads an ungated GGUF conversion, and the licence still applies to it.
Do not generalise from Neuphonic's other models. neutts-air is plain Apache-2.0 and the Nano models are 'other'; 2E is the restricted tier of the lineup.

What about the audio you generate?

No formal acceptable-use policy. Every audio file NeuTTS generates carries a Perth perceptual watermark by default. That matters if you plan to ship the audio; it is a property of the output, not a claim on it.

Correction to the shipped catalog: audio.cpp's conversion table lists this package as Apache-2.0, and the shipped catalog lists it as Unknown. Neither matches the upstream licence file, which is a custom licence with a $5M revenue cap and a download gate. This page follows the upstream terms and shows the restriction. For Apache-2.0 terms in this family, use neutts-air.

Based on the licence text as of the date below. Licences change; the links carry the authoritative version.

Specs

Transcribed from the shipped catalog, audiocpp_models_catalog.json — that file is authoritative if a number here disagrees with it.

Vendor: Neuphonic
Catalog id: audiocpp-neutts-2e
audio.cpp loader family: neutts
Can do: Text to speech
Weights repo: audio-cpp/audio.cpp-gguf
Weights file: NeuTTS-2E-GGUF/neutts-2e-orig.gguf
Account needed to download: No
Max clip length: 60s
Sample rate: 44.1kHz mono
Approx. VRAM: 3.7 GB
In the picker by default: No — opt in from Settings
Run end-to-end here: No — catalogued, not tested here

Getting it

There is no per-model install. One native binary runs all of these, so getting a model is a download of its weights and nothing else — no virtualenv, no torch pin, no CUDA wheel to match against your driver.

From the CLI

soundbox model install audiocpp
soundbox pull audiocpp-neutts-2e

The binary is fetched from audio.cpp's GitHub releases the first time you ask for it and cached under your own data directory. Soundbox ships no native binaries and vendors none.
Weights land in <models dir>/audiocpp/audiocpp-neutts-2e/ rather than in the shared Hugging Face cache, so a download stays scoped to the model you asked for.
This one is opt-in: switch it on in the Models page's “Enable more models” section before it appears in the picker.

Worth knowing

Opt-in and untested here. The original weights are gated upstream; the GGUF download is ungated, and the licence still applies.

Sources

Primary sources: the model's own repository, the project it came from, and the conversion audio.cpp actually downloads. Never invented — an entry with nothing findable says so instead.

Licence details on these pages are summaries of the linked source documents, last checked 25 August 2026. They are not legal advice, and Soundbox is not affiliated with any model's authors — weights download from Hugging Face under the user's own account and terms. Company and model names identify whose work it is, and belong to their owners. The linked licence text is authoritative; commercial use should be checked against it, per model, before anything ships.