Speech Studio

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A Soniqo project.

Open-source desktop app for content creators. Clone a voice from a short reference clip, write a script line by line, and synthesize the whole thing in that voice — with inline emotion markers for tone.

30-second demo

A blind A/B/C — a real voice, the same voice cloned locally by Speech Studio on a MacBook, and the same voice cloned by ElevenLabs in the cloud. Can you tell which is which?

Watch on YouTube → (30 sec)

Status: v0 — audio-only MVP. Runs on macOS 15+ (Apple Silicon) and Windows / Linux (x86_64): macOS clones via MLX, Windows/Linux via speech-core's on-device LiteRT backend. Video playback against the timeline and an audio-over-video export step are on the roadmap.

What it does

1. Drop a short reference clip of a speaker → register a cloned voice. Repeat for as many speakers as you need.
2. Write a script line per clip and pick which speaker says it. Wrap the line in an emotion marker — (whispering) Just stay quiet for a moment, please. — and the synth will follow that direction.
3. Hit Synthesize to render every line in the assigned cloned voice. The synth pipeline auto-grades each take with on-device ASR and retries with a different seed if the line came out wrong.
4. Play the script to hear the whole scene back-to-back. Export a single WAV mix (export wiring is in progress).

The clone is local. The synth is local. No audio leaves your machine.

Stack

• Tauri 2 shell (Rust + the OS-native WebView) so the shipped app is a small native binary, not a Chromium fork.
• React + Vite frontend for the timeline, voice library, and script editor.
• A warm sidecar process holds the speech engine resident so per-line synthesis is fast after the first warm-up. Tauri spawns it once and talks NDJSON over stdin/stdout. On macOS this is the Swift sidecar (swift-sidecar/, MLX); on Windows/Linux the C++ sidecar (core-sidecar/, LiteRT).
• CosyVoice 3 is the default engine on macOS via speech-swift (MLX). Windows/Linux default to VoxCPM2 via speech-core (LiteRT). The toolbar lists the engines supported on the current OS: macOS includes VoxCPM2, Qwen3-TTS, Chatterbox (multilingual cloning across 23 languages), OmniVoice (600+ language cloning), Indic-Mio (Hindi/Indic emotion tags), and Fish Audio S2 Pro (experimental clone + bracket markers); Windows/Linux currently include VoxCPM2 and Indic-Mio through LiteRT.

Engines

Switch engine from the toolbar dropdown. The list is filtered to engines supported on the current OS.

Engine	Platforms	Backend	Voice cloning	Emotion markers	Languages
CosyVoice 3 · macOS default	macOS only	MLX	✅	style instructions	9
VoxCPM2 · Windows/Linux default	macOS · Windows · Linux	MLX / LiteRT	✅	style instructions	30
Qwen3-TTS	macOS only	MLX	✅ (ICL)	—	10
Chatterbox	macOS only	MLX	✅	intensity only¹	23
OmniVoice	macOS only	MLX	✅	restricted instruct²	600+
Indic-Mio	macOS · Windows · Linux	MLX / LiteRT	✅³	suffix tags	Indic
Fish Audio S2 Pro	macOS only	MLX	✅⁴	bracket tags	80+

CosyVoice 3, Qwen3-TTS, Chatterbox, OmniVoice, and Fish Audio S2 Pro remain macOS-only in Studio. VoxCPM2 and Indic-Mio are also available on Windows/Linux through speech-core's LiteRT backend.

¹ Chatterbox has no free-text style input — emotion markers map to an expressiveness/intensity level (more vs. less expressive), not a specific emotion.

² OmniVoice supports broad voice-design attributes such as accent, age, gender, pitch, and whisper. Studio only passes valid instruct vocabulary items: whisper maps directly, while emotion markers map to pitch hints (high pitch, low pitch, etc.). Strong emotions are approximations, not true emotional acting.

³ Indic-Mio is exposed as an experimental Hindi/Indic emotion-marker engine. It uses suffix tags such as <happy> / <angry> and clones from reference audio through WavLM → MioCodec global speaker embeddings. It does not need a reference transcript. Windows/Linux use the soniqo/Indic-Mio-LiteRT bundle and output 24 kHz WAV clips.

⁴ Fish Audio S2 Pro uses bracket markers such as [excited], [angry], and [whisper]. It needs an accurate reference transcript for cloning, and the public weights are research/non-commercial unless separately licensed.

Emotion markers

Wrap a line in a parenthetical tag to steer the prosody:

(dramatic) I never thought we'd make it this far.
(warm) I knew you would make it, no matter what.
(whispering) Just stay quiet for a moment, please.
(intense) Then we end this together. Tonight.

Supported tags include soft, warm, whispering, intense, excited, happy, calm, serious, surprised, sad, angry, dramatic, laughs.

How a marker is applied depends on the engine: VoxCPM2 and CosyVoice 3 turn it into a short natural-language style instruction (custom tags like (slow and dreamy) pass through verbatim); OmniVoice maps only known markers to its fixed instruct vocabulary (whisper or pitch hints) and drops anything unmappable; Chatterbox maps markers to an expressiveness/intensity level (it has no per-emotion control, only more vs. less expressive); Indic-Mio appends supported suffix tags like <happy>; Fish Audio S2 Pro appends bracket tags like [excited]; Qwen3-TTS ignores markers (they're stripped from the text).

Research note: strong Hindi emotion cloning

Current open-source/on-device candidates for Hindi voice cloning with stronger emotion control:

• VoxCPM2 remains the best product-fit baseline for Speech Studio: Apache-2.0, on-device, supports Hindi, and supports controllable voice cloning through natural-language style guidance. It still needs a Hindi emotion bake-off against the models below before we claim strong acting range.
• Fish Audio S2 Pro looks strongest for expressive control: 80+ languages, short-reference voice cloning, and inline free-form emotion/prosody tags such as [angry], [sad], [whisper], and [shouting]. It is now available as an experimental macOS engine, but its public model license is research/non-commercial unless separately licensed, so it remains outside the default path.
• Svara-TTS v1 is the most relevant Indic-specific open model: Apache-2.0, 19 Indian languages, tags such as <happy>, <sad>, <anger>, and <fear>, plus zero-shot adaptation paths. Exact speaker similarity is less proven than VoxCPM2/Fish, but it is a good candidate for Hindi emotion fine-tuning.
• Chatterbox Multilingual Hindi is the permissive small fallback: MIT, a dedicated Hindi checkpoint, and zero-shot voice cloning. Its control is mainly exaggeration/intensity rather than explicit angry/sad/crying-style acting.
• OmniVoice is best kept for broad language coverage. Its instruction space is fixed to voice-design attributes, so Studio treats whisper as real control and maps other markers only to pitch.

Useful references: VoxCPM2, Fish Audio S2 Pro, Svara-TTS v1, Chatterbox Hindi, OmniVoice.

Download

Grab the latest build from the releases page:

Platform	Artifact	Status
macOS (Apple Silicon)	.dmg	✅ Published
Windows (x86_64)	.msi / .exe	✅ Published
Linux (x86_64)	.deb / .AppImage	✅ Published

Every platform downloads its speech model on first run and caches it, so the installers stay small:

• macOS — .dmg (~46 MB); drag into /Applications. First run pulls the CosyVoice 3 MLX weights into ~/Library/Caches/qwen3-speech/; selecting VoxCPM2 later pulls its MLX weights (~5 GB for the default bf16, ~3 GB for the int8 option in the weights picker).
• Windows — .msi or the NSIS -setup.exe. The first selected LiteRT engine downloads into %LOCALAPPDATA%\speech-core: VoxCPM2-LiteRT is ~8.8 GB; Indic-Mio-LiteRT is ~2.6 GB.
• Linux — .deb or .AppImage. The first selected LiteRT engine downloads into ~/.cache/speech-core: VoxCPM2-LiteRT is ~8.8 GB; Indic-Mio-LiteRT is ~2.6 GB.

The VoxCPM2 LiteRT bundle is fp16 and needs ~10 GiB of free RAM to load — an 8 GB machine may fall short. Indic-Mio LiteRT is smaller on disk but still keeps several GB resident while loaded.

The macOS build is signed and notarized (from v0.0.5 on) — it opens like any other app, no Gatekeeper hoops. The Windows installers are still unsigned: SmartScreen needs More info → Run anyway.

Manual VoxCPM2 model download (macOS)

If the in-app download keeps failing on a flaky or slow network (Download stalled for …: no progress / Failed to download …), fetch the model yourself and place it where the app looks. Two pieces: the model weights and a small set of tokenizer files.

Option A — hf CLI (recommended: it resumes interrupted downloads):

pip install -U huggingface_hub

hf download aufklarer/VoxCPM2-MLX-int8 \
  --local-dir ~/Library/Caches/qwen3-speech/models/aufklarer/VoxCPM2-MLX-int8

hf download openbmb/VoxCPM2 \
  config.json tokenizer.json tokenizer_config.json \
  tokenization_voxcpm2.py special_tokens_map.json \
  --local-dir ~/Library/Caches/qwen3-speech-voxcpm2-tokenizer/models/openbmb/VoxCPM2

Option B — browser: download the files from aufklarer/VoxCPM2-MLX-int8 and openbmb/VoxCPM2 into the same two directories. Minimum set: the model directory needs config.json plus every *.safetensors file; the tokenizer directory needs the five files listed in the command above.

The app detects the files on the next launch and skips the download entirely. The commands above fetch the int8 weights, so pick int8 in the toolbar's weights picker next to the engine selector (the default is bf16 — to pre-download that one instead, substitute aufklarer/VoxCPM2-MLX-bf16 in both places). Source builds launched from a terminal can also extend the in-app stall patience with HF_DOWNLOAD_STALL_TIMEOUT=<seconds>.

Build from source

Prerequisites

Common: Rust 1.95+ via rustup (. "$HOME/.cargo/env" if cargo isn't on PATH), Node 20+ and pnpm 11+.

• macOS: 15+ on Apple Silicon (M1/M2/M3/M4), Xcode 26+ (Swift 6.0 toolchain).
• Windows / Linux (x86_64): a C++17 toolchain + CMake 3.16+, and a built speech-core checkout with the LiteRT backend (-DSPEECH_CORE_WITH_LITERT=ON -DLITERT_DIR=...) and the HF downloader (-DSPEECH_CORE_WITH_HF_DOWNLOAD=ON) or local LiteRT bundles for VoxCPM2 / Indic-Mio.

Dev loop — macOS

pnpm install                          # installs the frontend + Tauri CLI
cd swift-sidecar && swift build       # builds the Swift sidecar
cd .. && pnpm tauri dev               # launches the app, hot-reloads the UI

The selected MLX engine downloads on first synth (into ~/Library/Caches/qwen3-speech/). For VoxCPM2 specifically, see Manual VoxCPM2 model download if your network keeps dropping it.

Dev loop — Windows / Linux

pnpm install
# Build the C++ sidecar against your speech-core checkout (defaults to ../speech-core):
cmake -B core-sidecar/build core-sidecar -DSPEECH_CORE_DIR=../speech-core
cmake --build core-sidecar/build --config Release
# Optional: point at pre-downloaded bundles instead of first-run HF downloads:
export SONIQO_VOXCPM2_BUNDLE_DIR=/path/to/speech-core/scripts/models-voxcpm2
export SONIQO_INDIC_MIO_BUNDLE_DIR=/path/to/Indic-Mio-LiteRT
# Optional: launch directly into Indic-Mio and tune parallel HF downloads:
export VITE_TTS_ENGINE=indic-mio
export SPEECH_CORE_DOWNLOAD_CONNECTIONS=4
pnpm tauri dev

On Windows PowerShell, use $env:VITE_TTS_ENGINE="indic-mio" / $env:SPEECH_CORE_DOWNLOAD_CONNECTIONS="4" before pnpm tauri dev.

Memory footprint

Measured on an Apple Silicon Mac (M-series, unified memory). The resident column is the real process footprint (Activity Monitor's "Memory" — vmmap physical footprint), which is the figure to check against your RAM. MLX active/peak is MLX's own accounting (peak is over a multi-line session). Note: plain ps rss under-reports by ~3× on Apple Silicon — Metal unified-memory buffers don't count as RSS, so use the resident figures below. The Activity panel shows the same footprint figure live after every load and render.

The selectable VoxCPM2 MLX engine:

Variant	Disk	MLX active	MLX peak	Resident (real)
aufklarer/VoxCPM2-MLX-int8	2.75 GB	3.1 GB	5.4 GB	~4–5 GB
aufklarer/VoxCPM2-MLX-bf16	4.6 GB	9.1 GB	11.4 GB	~12 GB

The macOS engines load separately when selected — only one is resident at a time (switching unloads the previous): Chatterbox ~4 GB resident (1.3 GB on disk), CosyVoice 3 lighter than VoxCPM2, Qwen3-TTS (1.7B bf16) heavier. OmniVoice is downloaded and loaded separately when selected.

The MLX buffer cache is capped at 1 GB (SONIQO_MLX_CACHE_MB to override) — without that cap, peak grows to tens of GB on long sessions as varying-shape buffers accumulate.

Engines that publish more than one set of weights show a weights picker next to the engine selector: VoxCPM2 (bf16 / int8), CosyVoice 3 (bf16 / 8-bit LLM / 8-bit LLM + DiT) and Qwen3-TTS (bf16 / 8-bit). Lower precision trades a little fidelity for a smaller download and less memory; switching reloads the engine, and the choice is remembered across launches.

Try the demo

Hit Load demo in the top bar. It bootstraps a Scene 04 storyboard with two cloned voices (Anna and Marek) and four lines of dialogue — one with each emotion marker — then synthesizes everything through the currently selected engine (CosyVoice 3 by default on macOS).

Activity log

The Activity button in the transport bar opens a live log of what the engine is doing: model downloads and loads, every synthesis step, and the sidecar's memory snapshots after each load and render (MLX active/peak plus the real process footprint). Copy puts the visible log on the clipboard for a bug report; Log file reveals the full, rotating file — ~/Library/Logs/audio.soniqo.studio/speech-studio.log on macOS, %LOCALAPPDATA%\audio.soniqo.studio\logs\ on Windows, ~/.local/share/audio.soniqo.studio/logs/ on Linux.

Packaging your own .app / .dmg

cd swift-sidecar && swift build -c release
cd .. && pnpm tauri build             # produces .app + .dmg under src-tauri/target/release/bundle/

Sibling repos

• speech-swift — Apple Silicon speech engines (VoxCPM2, CosyVoice3, Qwen3-TTS, Chatterbox, OmniVoice, Indic-Mio, Fish Audio S2 Pro, Parakeet, Silero VAD).
• speech-core — C++ engines (VoxCPM2 and Indic-Mio cloning on Windows/Linux, plus STT, VAD, denoise).

Contributing

See AGENTS.md for project conventions. Short version: branch → PR → merge, no force-pushes, no AI co-author trailers, never commit unless explicitly asked.

Licence

Apache License 2.0 — same as speech-swift and speech-core.