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Audio

16.6. Audio

10 TTS providers, from free to high-end

Hermes supports text-to-speech through 10 providers: Edge TTS (free), ElevenLabs, OpenAI TTS, MiniMax, Mistral Voxtral, Google Gemini, xAI, NeuTTS, KittenTTS, Piper — plus the ability to attach any local CLI TTS via a custom command provider.

Choosing a provider by purpose

NeedSuggestion
Creative content, the most natural voiceElevenLabs — high quality, supports cloning your own voice
Offline, private, no network neededPiper or KittenTTS — lightweight local engines
Already have a Nous Portal subscriptionOpenAI TTS via the Tool Gateway — no extra API key needed

How it works when playing long content

Hermes buffers each complete sentence, strips markdown/emoji/reasoning blocks before feeding them to TTS, then plays sentence by sentence in real time — with providers that support streaming (ElevenLabs, OpenAI), the latency to the first audio is the lowest.

Applications to content production

  • Turn a drafted article/newsletter into an audio version to publish as a podcast or voice message.
  • For long text that exceeds a provider’s per-request character limit, Hermes automatically splits it into sentence-level chunks and stitches them back together — no truncated content.

Notes

  • For public content (podcasts, videos), choose a provider that allows a consistent custom voice ID across generations — avoid the voice changing with every run, which breaks the identity.
  • For sensitive internal content that must be turned into audio, prefer a local provider (Piper/KittenTTS) so the data never leaves the machine — the same principle as choosing a read-only user for the database in chapter 11.3: keep the surface that handles sensitive data as narrow as possible.