Hume AI Octave 2
Emotionally expressive TTS and real-time speech-to-speech AI with voice cloning and human-feedback evaluation tools.
Hume Octave 2 is the go-to for emotionally expressive TTS and speech-to-speech, with 48+ emotions, 600+ voice descriptors, and granular turn/interruption controls. But the closed API and per-character overage mean you'll feel it in cost at high volume. Teams building voice products where nuance matters should pick it; anyone on a budget should look elsewhere.
Verified 10d ago · liveness 87/100 · cite: rightaichoice.com/tools/hume-ai-octave-2
- Developers building emotionally expressive voice assistants and conversational agents
- Game studios creating characters with dynamic vocal emotions
- Customer support bots that adapt empathy based on caller tone
- Voice AI researchers running human evaluation studies (via Human Feedback API and Kairos)
- Simple TTS tasks where emotional nuance isn't needed—ElevenLabs or Amazon Polly are cheaper
- Budget-constrained high-volume TTS—per-character overage costs add up fast
- Open-source licensing mandates (Octave and EVI are closed-source; consider TADA)
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Skip Hume Octave 2 if you need simple, high-volume TTS on a tight budget, require open-source licensing, or have strict latency requirements that prioritize speed over emotional nuance.
Going past 140,000 characters on Creator adds $0.15 per 1,000 characters, which can surprise you if you exceed your monthly quota.
Hume's freemium tier starts at $0/mo with 10k characters and 5 EVI minutes, scaling to $200/mo Scale for 3.3M characters and 5,000 EVI minutes. For budget-friendly high-volume TTS, ElevenLabs offers lower per-character costs, while Hume's per-character overage ($0.10-$0.15/1k beyond allowances) makes it pricier at scale. For emotionally rich, low-volume projects, Hume's included allowances are generous.
In short
Hume AI Octave 2 — Emotionally expressive TTS and real-time speech-to-speech AI with voice cloning and human-feedback evaluation tools. Best for Developers building emotionally expressive voice assistants and conversational agents, Game studios creating characters with dynamic vocal emotions, Customer support bots that adapt empathy based on caller tone. Free to start; paid plans from $3/mo.
What's new in Hume AI Octave 2
Checked 10 days agoAcross the latest 4 updates: 2 feature updates, 1 launch and 1 changelog entry.
Introducing Real World VoiceEQ: Measuring the Human Quality of Voice AI
Launched Real World VoiceEQ, a benchmark for voice AI quality across TTS, STS, SU, and ASR, providing transparent, human-based evaluation.
TTS API additions: experimental temperature parameter
Added experimental temperature parameter to TTS endpoints, letting you control sampling variation and consistency in generated speech.
EVI API additions: configurable turn detection and interruption
EVI now supports configurable turn detection (silence threshold, padding) and interruption settings (min interruption ms) for finer control over conversations.
EVI API additions and TTS bug fixes
EVI adds support for claude-opus-4-6, gpt-5.1/5.2 models, zero prompt expansion; fixes TTS duplicate audio bug.
Viability Score
How well maintained and how widely used is Hume AI Octave 2? Built from what the vendor actually publishes (docs, changelog, tutorials, integrations, pricing), whether the site is live, and how much real users discuss it. How we calculate this
Last calculated: September 2026
How we score →Key Features
- Text-to-speech (Octave 2) with emotional control across 48+ emotions
- 600+ voice descriptors for fine-grained expression tuning
- Speech-to-speech (EVI 4 mini) with real-time emotion adaptation
- Configurable turn detection: silence threshold, prefix padding
- Configurable interruption settings: min interruption ms
- Experimental temperature parameter for TTS variation
- Zero prompt expansion for external LLMs (GPT-5.2, Claude Opus 4.6)
- Voice cloning: unlimited on all paid tiers
- Voice conversion with commercial license (Creator and above)
- Human Feedback API with pre-screened raters
- Expression Measurement API for real-time/offline emotion analysis
- Kairos agent-to-agent simulation and regression testing
- RW-Voice-EQ Bench leaderboard ranking models by human judgment
- SLM Judge 1 leaderboard for automated evaluator trust
- RESTful API for evaluation studies and emotion tagging
About Hume AI Octave 2
Hume AI Octave 2 is a voice AI platform built on documented research in multimodal emotional intelligence. It pairs high-fidelity text-to-speech (TTS) with the Empathic Voice Interface (EVI) for real-time speech-to-speech conversation, letting developers tune not just what a voice says but how it feels. A single API call gives you access to 48+ emotions, 600+ voice descriptors, and support across 50+ languages—making it a fit for teams building assistants, game characters, or audiobook narrators that need to land jokes, reassurances, and empathy, not just read lines. The TTS engine (Octave 2) adds an experimental temperature parameter for adjusting sampling variation, so you can dial in consistency or creativity per output. EVI 4 mini brings configurable turn detection—silence threshold, prefix padding—and interruption settings (minimum interruption milliseconds) so you can control exactly how the system reacts to a caller's tone in live conversation. Voice cloning is unlimited across all paid tiers, and voice conversion carries a commercial license from the Creator tier up. You can also plug in external LLMs like GPT-5.2 or Claude Opus 4.6 via the zero prompt expansion option, reducing the need for heavy prompt engineering. Beyond generation, Hume positions itself as an evaluation layer. The Human Feedback API returns pre-screened raters' scores and free-response feedback in hours, the Expression Measurement API analyzes real-time and offline emotion (48+ emotions, 50+ languages, 600+ metrics), and Kairos simulates agent-to-agent conversations for regression testing. New leadership: RW-Voice-EQ Bench ranks text-to-speech and speech-to-speech models by human judgment, and SLM Judge 1 tells you which automated judges best track human ratings. Compliance (SOC 2 Type II, GDPR, HIPAA) is available on Business and Enterprise tiers. Hume's differentiator is emotional intelligence—the layer that determines whether users actually want to keep talking to a voice AI.
Behind the Verdict
Hume AI Octave 2 stands out in the voice AI space by focusing on emotional intelligence—the layer that determines whether users actually want to keep talking to a voice AI. The TTS engine doesn't just read text; it understands context and delivers expressive, context-aware speech. With 48+ emotions and 600+ voice descriptors, you can fine-tune tone, pacing, and accent to match your use case. The EVI 4 mini adds real-time speech-to-speech with configurable turn detection and interruption settings, letting you control exactly how the system reacts in live conversation. What sets Hume apart is its evaluation stack. The Human Feedback API, Expression Measurement API, and Kairos platform let you measure and refine your voice AI's performance with real human judgment. The RW-Voice-EQ Bench and SLM Judge 1 leaderboards provide industry benchmarks for voice quality and automated evaluator trust. However, there are trade-offs. The closed API and per-character overage costs can add up at high volume. The free tier is limited to 10,000 characters per month and 15 RPM, so you'll likely need a paid plan for serious development. Also, the focus on emotional intelligence means it may be overkill for simple TTS tasks where ElevenLabs or Amazon Polly would suffice. Open-source licensing mandates might also be a blocker, as Octave and EVI are closed-source. Where it fits: developers building emotionally expressive voice assistants, conversational agents, game characters, and digital companions. Where it doesn't: budget-constrained high-volume TTS, latency-critical production systems, or teams with open-source licensing requirements.
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Real-world workflow fit
Concrete scenarios for the personas Hume AI Octave 2 actually fits — and what changes day-one when you adopt it.
Create expressive character voices for a narrative RPG with emotional arcs.
Outcome: Use Octave 2 TTS to generate character voices with configurable emotions and descriptors, then fine-tune temperature for consistency. With unlimited voice cloning, you can maintain unique voices across many NPCs.
Deploy an empathetic voice assistant that adapts tone to caller emotions.
Outcome: Integrate EVI 4 mini via SDK (e.g., LiveKit) to handle real-time speech-to-speech with turn detection and interruption settings. Use Expression Measurement API to track caller emotions and refine responses.
Evaluate TTS models for naturalness and emotional expressiveness.
Outcome: Use Human Feedback API to get pre-screened raters' scores and feedback in hours. Leverage RW-Voice-EQ Bench to compare models, and Kairos to simulate conversations for regression testing.
Use Cases
- Create audiobooks with character-specific voices and emotional arcs
- Generate personalized voice messages for apps or campaigns with tone control
- Produce multilingual e-learning content with emotionally varied narration
- Build digital companions that adapt their voice to user mood
- Develop voice-overs for videos that match scene emotions dynamically
- Simulate lifelike interviews or coaching sessions with dynamic tone adjustment
- Empathetic customer support bots that recognize and convey empathy
- Run human evaluation studies on TTS output using the Human Feedback API
Models Under the Hood
as of 2026-08-31
Limitations
- Pricing tiers vary from Free ($0/month) to Enterprise (custom), with included character amounts and EVI minutes scaling accordingly.
- Overage costs apply for additional characters and EVI usage beyond plan inclusions.
- The free tier is limited to 10,000 characters per month and 15 RPM.
as of 2026-08-28
Verification history
We have re-verified Hume AI Octave 2 16 times since . Each pass re-reads the vendor's own pages and re-checks every listed field against that evidence; passes where nothing had changed are marked as such.
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-checked, vendor evidence unchanged
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
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Free to cite with attribution — this page re-verifies continuously.
12-month cost
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
Plans compared
For each published Hume AI Octave 2 tier: who it actually fits, and what it adds vs. the previous tier. Cross-reference the cost calculator above for projected annual outlay.
Free
$0/mo
Ideal for
Solo developers exploring emotionally expressive TTS and EVI with low-volume needs (10k chars, 5 EVI min/mo).
What this tier adds
Starting tier with 10k characters, 5 EVI minutes, 1 concurrent external LLM, and Discord support.
Starter
$3/mo
Ideal for
Hobbyists testing early prototypes with 30k chars and 40 EVI minutes at a low cost ($3/mo first month).
What this tier adds
Adds 30k characters, 40 EVI minutes, 5 concurrent external LLM connections, first month 50% off.
Creator
$7/mo first month, $14/mo thereafter
Ideal for
Content creators and indie devs needing commercial voice conversion and more volume (140k chars, 200 EVI min).
What this tier adds
Adds commercial license for voice conversion, 140k chars, 200 EVI minutes, and higher RPM (75).
Pro
$70/mo
Ideal for
Growing teams with higher volume needs (1M chars, 1,200 EVI min) and team collaboration.
What this tier adds
Adds 1M characters, 1,200 EVI minutes, 10 concurrent external LLMs, and 3 team seats.
Scale
$200/mo
Ideal for
Established products requiring high volume (3.3M chars, 5,000 EVI min) with more concurrency.
What this tier adds
Adds 3.3M characters, 5,000 EVI minutes, 20 concurrent external LLMs, and 3 team seats.
Business
$500/mo
Ideal for
Organizations needing compliance (SOC 2, GDPR, HIPAA) and high volume (10M chars, 12,500 EVI min).
What this tier adds
Adds 10M characters, 12,500 EVI minutes, 30 concurrent external LLMs, compliance, and 5 team seats.
Enterprise
Custom
Ideal for
Large enterprises with custom needs for unlimited usage, API access to voice cloning, and dedicated support.
What this tier adds
Custom pricing, unlimited usage, API access to voice cloning, and dedicated Slack support.
Where the pricing makes sense
The company stage and team size where Hume AI Octave 2's pricing actually pencils out — and where peers do it cheaper.
Hume's freemium tier starts at $0/mo with 10k characters and 5 EVI minutes, scaling to $200/mo Scale for 3.3M characters and 5,000 EVI minutes. For budget-friendly high-volume TTS, ElevenLabs offers lower per-character costs, while Hume's per-character overage ($0.10-$0.15/1k beyond allowances) makes it pricier at scale. For emotionally rich, low-volume projects, Hume's included allowances are generous.
Setup time & first value
How long it actually takes to get something useful out of Hume AI Octave 2 — broken out by persona, not the marketing-page minute.
For developers, initial setup with SDKs (Python, TypeScript) can take a few hours to get API keys and run first TTS call. Full integration of EVI (speech-to-speech) may take a few days to configure turn detection and test. For researchers, setting up Human Feedback studies can be done in hours via the API.
Switching to or from Hume AI Octave 2
How to bring data in from common predecessors and how to get it back out — written for the switcher, not the buyer.
- →From ElevenLabs: Replace TTS calls with Hume's Octave 2 API, adjust for emotional parameters, and map voice IDs to Hume's voice library or custom clones.
- ↗To ElevenLabs: If you need cheaper high-volume TTS, migrate by replacing Hume API calls with ElevenLabs endpoints, noting lower emotional granularity.
- ↗To open-source TTS like TADA: If open-source licensing is required, export voice configurations and retrain models on your own infrastructure.
Integrations
Resources & Guides
- Documentationhume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Quickstarthume.ai
Quickstart
Get up and running fast from hume.ai
- Documentationhume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Documentationhume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Documentationhume.ai
Continuation
Full product docs from hume.ai
- Documentationhume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Documentationhume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Quickstarthume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Quickstarthume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
- Documentationhume.ai
Welcome to Hume AI | Hume API
Hume AI builds AI models that enable technology to communicate with empathy and support human well-being.
Tutorials & Learning
Official links
Tools that pair well with Hume AI Octave 2
Common stack mates teams adopt alongside Hume AI Octave 2, with the specific reason each pairing earns its keep.
Alternatives to Hume AI Octave 2
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Fish Audio
Free expressive text-to-speech and voice cloning platform with emotion control and a free API.
Frequently Asked Questions
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