Natural-sounding text-to-speech with twenty voices, ten languages and voice
cloning.
loudr-1 runs on your own hardware through
loudkit. Download it once and work offline
from Python, Swift, Go, Rust or TypeScript with PyTorch, ONNX Runtime or CoreML.
Both voices read the same passage from Alice's Adventures in Wonderland.
Open the gallery to compare every
shipped voice with the enrollment reference used to create its profile.
English is the only language we could evaluate ourselves by ear. We do not
speak the other nine languages well enough to judge their naturalness
reliably. If you do, please listen and share what sounds good or wrong.
Feedback from native speakers is very welcome.
Start in Python
pip install "loudkit[torch,audio,hub]"
python
1import loudkit as lk
23engine = lk.load("loudreader/loudr-1")4voice = lk.voice("joe", repo="loudreader/loudr-1")56engine.synthesize("Hello from loudkit.", voice, seed=7).save("hello.wav")
The first run downloads the 747 MB synthesis checkpoint and the voices. Later
runs use the local cache. The same path from a shell is:
bash
1loudkit speak --checkpoint loudreader/loudr-1 --voice joe \2"Hello from loudkit." -o hello.wav
To enroll a voice that you own or have permission to use:
The reusable profile is about 150 KB. Install
loudkit[torch,audio,enroll,hub] for enrollment.
Choose your runtime
The repository contains all supported formats, but the downloader fetches only
the runtime you select. Add --with-cloning when the installation also needs
enrollment.
path
command
download
Python, synthesis
loudkit download loudreader/loudr-1 --for torch
750 MB
Python, with cloning
--for torch --with-cloning
1.28 GB
JS, Go or Rust with ONNX
--for onnx
2.60 GB
ONNX, with cloning
--for onnx --with-cloning
3.13 GB
Swift or Python with CoreML
--for coreml
1.16 GB
CoreML, with cloning
--for coreml --with-cloning
1.69 GB
Add --local-dir loudr-1 to create a portable directory instead of using the
shared cache. The synthesis checkpoint will be at
loudr-1/loudr-1.safetensors.
Measured speed
path
hardware
real-time factor
PyTorch with CUDA graphs
RTX 3090
7.47x
PyTorch with CUDA graphs
Jetson Orin Nano
1.83x
split PyTorch engine*
Apple M3 Pro
3.43x
ONNX Runtime, CPU provider
Apple M3 Pro
1.21x
PyTorch CPU reference
Apple M3 Pro
0.33x
* "Split" describes device placement, not a different model or checkpoint.
The token generator runs on the CPU while the mel and vocoder renderer runs on
the Apple GPU through MPS. Adjacent windows can overlap across the two devices.
Higher is faster, and 1.0x means real time. ONNX Runtime on the measured M3 Pro
CPU is faster than real time. The PyTorch CPU reference path on the same machine
is not.
For batched workloads, the token generator reaches 20.1x aggregate throughput
at batch 1 and 153.1x at batch 64 on the RTX 3090. The highest measured result
is 170.8x on an A100 at batch 64. These are generator-only throughput numbers,
not single-request latency or end-to-end RTF. See the
benchmark report for commands,
hardware and caveats.
What ships
artefact
size
used by
loudr-1.safetensors
747 MB
synthesis
loudr-1-enrollment.safetensors
523 MB
PyTorch enrollment
ve.safetensors
5.7 MB
PyTorch enrollment
onnx/
2.38 GB
nine graphs: six synthesis, three enrollment
coreml/
941 MB
six packages: three synthesis, three enrollment
voices/
3.1 MB
twenty voice profiles
samples/
108 KB
the two players above
tokenizer.json
70 KB
text processing
Synthesis and enrollment are separate so users who only need speech generation
do not download the enrollment weights. ONNX and CoreML use their own enrollment
graphs. loudkit also verifies that paired model files came from the same source
checkpoint.
Voices and consent
The release includes two profiles for each of these languages: English,
Spanish, French, German, Italian, Polish, Portuguese, Dutch, Swedish and Danish.
The profiles were built from recordings donated for speech technology or from
CC0 and CC-BY speech corpora. No scraped celebrity voices ship with the model.
The full roster records
the source, licence and consent basis for every profile. The
voice gallery provides a generated
sample and enrollment preview for all twenty.
The source enrollment WAVs are not redistributed in the model repository. Their
digests, construction notes and the digests of every shipped profile and sample
are recorded in
provenance.json.
Model lineage
loudr-1 is derived from
Chatterbox, released by Resemble AI
under the MIT licence. We optimized it for faster local inference by profiling
the full synthesis path, changing the signal flow, separating synthesis from
enrollment, and adjusting graph boundaries and device placement for PyTorch,
ONNX Runtime and CoreML.
Release gates compare the implementations, check output length and early end of
speech, and run ASR-based checks per measured language. These checks catch
mechanical regressions. They do not replace listening by native speakers.
Reproducibility
For a fixed build, device and backend, the same text, voice and seed produce the
same waveform. Across devices or backends, loudkit checks the token stream and
keeps waveform differences inside measured correlation bands. Floating-point
execution means that waveforms are not promised to be byte-identical across
different runtimes.
Long passages are rendered in windows of about ten seconds. Sentence joins
can occasionally be audible.
Difficult punctuation, numbers and abbreviations can change pronunciation or
prosody.
Voice cloning requires consent. A recording being public does not grant
permission to clone the speaker.
Saved WAVs and server responses include an unsigned C2PA Content Credentials
manifest by default. It records the model, voice, seed, backend and audio
digest in a machine-readable form.
Read Responsible use
before exposing enrollment to other people.
Intended use
loudr-1 is intended for local narration, accessibility, localisation, games,
prototyping and speech research. It is not a voice-authentication system and
must not be used for deceptive impersonation.
Training data
The original Chatterbox training data is controlled by Resemble AI and is not
documented by this project. The shipped voice profiles use recordings made or
released for speech-technology use; their sources and licences are listed in
the public roster.
Licence
Apache-2.0.
Upstream attributions and component licences are listed in
NOTICE.