CastleFlow v1.0 text-to-speech model
async
CastleFlow v1.0 is a text-to-speech (TTS) model from async. It has no Artificial Analysis score yet. On TTS Arena V2 it scores Elo 1551 (±21, 1,643 votes).
Key facts
- Provider
- async
- AA rank
- –
- AA Elo (95% CI)
- –
- AA samples
- –
- TTS Arena Elo (uncertainty)
- 1551 ±21
- TTS Arena votes
- 1,643
- TTS Arena win rate
- 60.1%
- Price (per 1M chars)
- –
- Released
- –
- Open weights
- –
- License
- –
- Voices tested by AA
- –
- Languages
- –
- Voice cloning
- –
"–" means the upstream sources do not provide this value; we do not guess.
Nearby models
By TTS Arena Elo; this model highlighted| # | Model | AA Elo | Arena Elo | Price $/1M chars | Open weights |
|---|---|---|---|---|---|
| 1 | EAudio8-TTS-Realistic-0.6B Edge0 | – | 1735 | – | – |
| 2 | GGradium TTS 2026.10 Gradium | – | 1613 | – | – |
| 3 | ?Aurora | – | 1563 | – | – |
| 4 | ACastleFlow v1.0 async | – | 1551 | – | – |
| 5 | IInworld TTS MAX Inworld | – | 1548 | – | – |
| 6 | ?star-june-2026 | – | 1545 | – | – |
| 7 | PPapla P1 Papla | – | 1540 | – | – |
Alternatives · More from async
| # | Model | AA Elo | Arena Elo | Price $/1M chars | Open weights |
|---|---|---|---|---|---|
| 31 | AAsync Flash v1.5 async | 1141 | – | $10.1 | – |
| 34 | AAsync Pro v1.0 async | 1128 | – | $20.2 | – |
| 66 | AAsync Flash v1.0 async | 1050 | – | $10.1 | – |
Alternatives · Top 5 open-weight by AA Elo
| # | Model | AA Elo | Arena Elo | Price $/1M chars | Open weights |
|---|---|---|---|---|---|
| 9 |  Fish Audio Drama 3 Preview Fish Audio | 1248 | – | $15 | Open |
| 11 | BBreeze TTS 2 BreezeBlue | 1230 | – | $34 | Open |
| 19 |  Ming-3.0-tts Ant Group | 1191 | – | – | Open |
| 38 | Fish Audio S2 Pro Fish Audio | 1110 | – | $15 | Open |
| 41 |  Step Audio EditX (Mar 2026) StepFun | 1100 | – | – | Open |
FAQ
Where does CastleFlow v1.0 rank among TTS models?
As of Oct 25, 2026, CastleFlow v1.0 has no Artificial Analysis score; its TTS Arena V2 Elo is 1551 (1,643 votes).
Is CastleFlow v1.0 open source?
The sources do not list CastleFlow v1.0 as open-weight; it is generally used through the async API.
What is the best Chinese TTS model?
By AA Elo, the top model from a Chinese provider is Qwen-Audio-3.1-TTS-Plus by Alibaba (Elo 1307, #3 overall).
Which top-10 TTS model is cheapest?
Among the AA top 10, the lowest list price is Simba 3.2 (SpeechifyAI) at $6.6 per 1M characters, Elo 1246.
What is the best open-source TTS model?
By AA Elo, the top open-weight model is Fish Audio Drama 3 Preview by Fish Audio (Elo 1248, #9 overall); 18 open-weight models have an AA score.
Sources
"–" means the upstream sources do not provide this value; we do not guess.