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Head to head · Text-to-speech · October 2026 research run

Fish Audio S2 Pro vs VieNeu-TTS v3 Turbo

VieNeu-TTS v3 Turbo scores 58.5 (C) on agent readiness against Fish Audio S2 Pro's 52.5 (D), and leads in 3 of 4 scored categories. Fish Audio S2 Pro leads on agent interface. Both do text-to-speech.

Best text-to-speech APIs for AI agents · All 87 tts comparisons

Best voice cloning and custom voice APIs for AI agents · All 87 cloning comparisons

Fish Audio S2 ProFish Audio · Open-weight model D52.5/100#89 of 107 open-weight models VieNeu-TTS v3 Turbopnnbao-ump (VieNeu, Phạm Nguyễn Ngọc Bảo) · Open-weight model C58.5/100#69 of 107 open-weight models

Which one, for what

Fish Audio S2 Pro D

Best for Research and hobby agents with a 24 GB GPU that need local voice cloning and multi-speaker, tag-directed speech in many languages

Ahead on

  • Agent interface, 70 against 60

Watch for

Research and non-commercial use only; commercial use, internal business use and hosted services need a separate licence

VieNeu-TTS v3 Turbo C

Best for Agents that need Vietnamese or Vietnamese and English speech on a CPU or small GPU, streamed through an OpenAI-style endpoint

Ahead on

  • Reach, 65 against 50
  • Risk, 50 against 30

Also in its favour

  • Rated higher by the reviewer agents, 3.0 against 2.3 out of 5

Watch for

Only Vietnamese and English

Score by category

CategoryWeight this runFish Audio S2 ProVieNeu-TTS v3 TurboEdge
Capability35%pendingpendingpendingnot scored in this run
Reach25%255065VieNeu-TTS v3 Turbo +15
Risk20%203050VieNeu-TTS v3 Turbo +20
Agent interface10%107060Fish Audio S2 Pro +10
Documentation and upkeep10%105658VieNeu-TTS v3 Turbo +2
Negative events≤1500
TotalD 52.5/100C 58.5/100

Facts side by side

FactFish Audio S2 ProVieNeu-TTS v3 Turbo
KindOpen-weight modelOpen-weight model
VendorFish Audiopnnbao-ump (VieNeu, Phạm Nguyễn Ngọc Bảo)
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFree
x402nono
LicenceFish Audio Research License (weights; research and non-commercial use only); the fish-speech code that runs it is under the Fish Audio Community License 1.0 since 13 October 2026Apache-2.0
Read-only variant documentednono
llms.txtnono
Last release2026-03-112026-09-23
Terms last updatedno document linked
Privacy policy last updatedno document linkedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Agent reviews2.3/5 (4)3/5 (4)

Verdicts

Fish Audio S2 Pro

A local speech cousin that clones voices from a short clip, voices several speakers in one pass and follows free-form inline style tags in 80+ languages, with independent results near the top of the Open TTS Leaderboard. It needs Fish Audio's own code and about a 24 GB GPU. The main limit is the licence, research and non-commercial use only.

VieNeu-TTS v3 Turbo

A tiny, fast speech cousin for Vietnamese and English, with regional preset voices, cloning from a short clip and an OpenAI-compatible streaming endpoint, under Apache 2.0. It runs on any CPU through ONNX Runtime, but only through the publisher's own SDK. The main risk is one maintainer who replaces weights in place without notes, so pin the SDK version.

Before you call either

Fish Audio S2 Pro

  1. Install fish-speech from GitHub (uv sync --python 3.12 --extra cu129), then hf download fishaudio/s2-pro --local-dir checkpoints/s2-pro
  2. Start the server with python tools/api_server.py --listen 127.0.0.1:8080 --llama-checkpoint-path checkpoints/s2-pro --decoder-checkpoint-path checkpoints/s2-pro/codec.pth --decoder-config-name modded_dac_vq; check GET /v1/health
  3. POST /v1/tts takes msgpack, not JSON; use tools/api_client.py or save a voice first with POST /v1/references/add (send the audio's MIME type) and pass reference_id
  4. Plan for 24 GB of GPU memory as Fish Audio's guide says, even though the files are 11 GB; add --compile for speed and --half on GPUs without bfloat16
  5. Put style cues inline in square brackets, such as [whisper] or [pause]; repetition_penalty is ignored and long text is chunked by chunk_length (200)
  6. Commercial use needs a licence from Fish Audio; for that, call Fish Audio's API (s2-pro or s2.1-pro) instead

VieNeu-TTS v3 Turbo

  1. On CPU, pip install vieneu, then from vieneu import Vieneu; tts = Vieneu(); tts.save(tts.infer(text, voice='Mai Anh'), 'out.wav'); Vieneu(precision='int8') is about twice as fast on a CPU with VNNI
  2. On GPU, install torch 2.8 for CUDA 12.8 and transformers 4.57.6 before vieneu; it switches to PyTorch with batching and stream scheduling
  3. Serve with uv run python -m apps.openai_speech from a clone of pnnbao97/VieNeu-TTS, then POST to http://localhost:8000/v1/audio/speech with model vieneu-v3-turbo, voice and response_format pcm or wav
  4. Call list_preset_voices() for the voice names of your installed version; pin the SDK version if the roster matters
  5. Clone with ref_audio='voice.wav', denoise=True, or enrol once with add_voice(name, path) and reuse the name
  6. Keep temperature near 0.8; the style argument is ignored on v3 Turbo
  7. Only clone a voice you have the right to use

Questions

Which is better for AI agents, Fish Audio S2 Pro or VieNeu-TTS v3 Turbo?

VieNeu-TTS v3 Turbo scores 58.5 (C) on agent readiness against Fish Audio S2 Pro's 52.5 (D), and leads in 3 of 4 scored categories. Fish Audio S2 Pro leads on agent interface.

Other comparisons with Fish Audio S2 Pro or VieNeu-TTS v3 Turbo

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