As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/hume-octave-2/

# Hume Octave 2 (TTS)

Hume AI, Octave family. Status: current. Type: speech and audio. Released: 2025-10-01.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Hume API | `version: 2` | https://api.hume.ai/v0/tts | https://dev.hume.ai/docs/text-to-speech-tts/overview |
| Web app |  |  | https://platform.hume.ai |

## Pricing

- Per 1K characters: $0.15
- Unit as published: per 1K characters overage on Free/Starter/Creator plans; $0.12 Pro, $0.10 Scale, $0.05 Business (plans include monthly character quotas)
- Source: https://www.hume.ai/pricing
- Last checked: 2026-09-29

## Specs

- Input: text, audio
- Output: audio
- Context window: not published
- Max output: not published
- Open weights: no
- Licence: proprietary

## Where it stands

- Newer speech and audio models in the registry since its release: 84. The 5 newest:
  - NVIDIA Nemotron 3.5 Transcribe (30B-A4B) (2026-10-28) https://postcutoff.com/m/nemotron-3-5-transcribe/
  - Hy-SimulMT-30B-A3B (2026-10-22) https://postcutoff.com/m/hy-simulmt-30b-a3b/
  - Eleven Realtime v1 Max / Mini (2026-10-20) https://postcutoff.com/m/eleven-realtime-v1-max/
  - Voxtral Mini Transcribe 3 (+ Mini Transcribe Realtime 3) (2026-10-20) https://postcutoff.com/m/voxtral-mini-transcribe-3/
  - Voxtral Small Transcribe 3 (2026-10-20) https://postcutoff.com/m/voxtral-small-transcribe-3/
- Before it from Hume AI: Hume EVI 3 / EVI 4 mini (speech-to-speech) (2025-05-29) https://postcutoff.com/m/hume-evi/
- Closed weights; access is hosted only.

## What stands out

- LLM-based emotionally intelligent TTS: Speech-language model that infers emotion and delivery from text; natural-language 'acting instructions' steer tone. Octave 2 at half the price of Octave 1, ~100 ms model latency (docs) / under 200 ms (launch blog). Source: https://www.hume.ai/blog/octave-2-launch
- 11 languages, instant cloning from 15 s: Arabic, English, French, German, Hindi, Italian, Japanese, Korean, Portuguese, Russian, Spanish; instant voice cloning from a ~15 s recording with accent prediction across languages; voice design from a text prompt (English only). Source: https://dev.hume.ai/docs/text-to-speech-tts/overview
- Voice conversion and phoneme editing: Launch post describes voice conversion (swap speaker) and direct phoneme-level pronunciation editing as new capabilities for a speech-language model. Source: https://www.hume.ai/blog/octave-2-launch

## Notes

Select via `version: 2` in the TTS request body (`1` = Octave 1, English/Spanish, ~200 ms). Docs still label Octave 2 '(preview)' as of 2026-09-29. Auth header X-Hume-Api-Key. Max 5,000 chars per utterance, 1,000-char descriptions. Formats MP3/WAV/PCM. No Octave 3 announced on Hume's blog through Sept 2026. Speech-to-speech sibling: see hume-evi.

Emotionally expressive TTS from Hume AI (Octave = "Omni-capable text and voice engine").

```bash
curl https://api.hume.ai/v0/tts -H "X-Hume-Api-Key: $HUME_API_KEY" -H "Content-Type: application/json" \
  -d '{"version":2,"utterances":[{"text":"I cannot believe it worked!","description":"a delighted, breathless scientist"}]}'
```

Sources: https://dev.hume.ai/reference/text-to-speech-tts/synthesize-json , https://www.hume.ai/pricing , https://www.hume.ai/blog/octave-2-launch

Model page: https://postcutoff.com/m/hume-octave-2/