Voice AI•July 29, 2025•3 min read
A comprehensive guide to the best TTS models for voice AI agents in 2025, including ElevenLabs, OpenAI, Deepgram, Cartesia, Rime, and open-source options.
Choosing the right text-to-speech (TTS) model for your voice AI agent is critical. Latency, voice quality, language support, and pricing all matter. This guide covers the best options available in 2025.
ElevenLabs Flash v2.5
ElevenLabs Flash is a popular, ultra-low-latency multilingual text-to-speech voice model. Flash is ElevenLabs' fastest model — ideal for real-time voice agents. Flash 2.5 boasts sub-100ms TTFB in 30+ languages, and preserves high voice quality. The model also sets the bar for high-fidelity 5-second voice cloning.
✅ Pros
- Very fast start-up (~75 ms)
- Best-in-class multilingual voice cloning quality
❌ Cons
- 2nd highest cost (of evaluated models)
- Closed ecosystem
OpenAI GPT-4o mini TTS
OpenAI's GPT-4o mini TTS is a text-to-speech model built on GPT-4o mini that supports 32 languages and a wide range of customizable expressions via prompting. Average TTFB hovers at just under a quarter-second.
✅ Pros
- Tight integration with OpenAI toolchain
- Prompt-level style control
❌ Cons
- No voice cloning
Deepgram Aura-2
Deepgram Aura-2 TTS model targets enterprise voice agents. Aura-2 boasts under 200ms TTFB latency and simple, per-character pricing.
✅ Pros
- Affordable pricing for high call volumes
- Fast start-up (under 200ms)
❌ Cons
- English and Spanish only
- No voice cloning
Cartesia Sonic 2.0
Cartesia Sonic is known for ultra-low latency and excellent multilingual support.
✅ Pros
- Ultra-low latency & 15 languages
- Instant, good quality voice cloning
❌ Cons
- Closed-source
Rime Mist v2
Rime Mist offers consistently low latency with no concurrency limits.
✅ Pros
- Consistently low latency & no concurrency limits
- Professional cloning tier for brand voices
❌ Cons
- Only two languages
- Good but not excellent voice quality
Rime Arcana
Rime Arcana focuses on expressive, natural-sounding speech.
✅ Pros
- Expressive, natural sounding speech
- Highly customizable via emotion tags
❌ Cons
- Slower than Rime's Mist model
- Closed-source
Open-source options
Orpheus (Canopy Labs)
✅ Pros
- Free, open weights with permissive license
- 7 languages (impressive for open-source)
❌ Cons
- Nontrivial to set up & configure
Dia 1.6B
✅ Pros
- One of the most lifelike voice and pacing
- Fully open for research or batch synthesis
❌ Cons
- No real-time support
- English only
Sesame CSM-1B
✅ Pros
- Free & self-hostable
- Basic voice cloning
❌ Cons
- Not as impressive as Sesame's viral demo
Coqui XTTS v2.0.3
✅ Pros
- Open-source with good community support
- Multi-language support
❌ Cons
- Requires self-hosting
- Higher latency than commercial options
Conclusion
For production voice AI agents, we recommend ElevenLabs Flash v2.5 or Cartesia Sonic for the best balance of latency and quality. If cost is a primary concern, Deepgram Aura-2 or Rime Mist are excellent choices.
All of these models are available on Layercode. Get started building your voice AI agent today.