Voice AI Benchmark Report · March 2025

The Voice AI Benchmark. Opal leads the field.

Speed. Intelligence. Audio reasoning. This Voice AI benchmark compares Deepslate Opal against OpenAI, Gemini, ElevenLabs, and more.

Benchmark 01 · Latency

Faster than human reaction time.

In this Voice AI benchmark, latency is felt in milliseconds and noticed in seconds. At 250ms time-to-first-audio-byte, Deepslate Opal enables natural, flowing conversations from EU-hosted infrastructure.

Time-to-First-Audio-Byte

Lower is better · EU Region · March 2025

LIVE
Deepslate Opal
250ms
OpenAI Realtime
420ms
Gemini Live
470ms
ElevenLabs Turbo v2
530ms
Azure TTS Neural
650ms
Deepslate Opal
Competitor

Tau2-Telecom Bench

Accuracy (%) · Higher is better · v1.4

INTELLIGENCE
Deepslate Opal
71%
Claude 3.7 Sonnet
64%
GPT-5.2
62%
Gemini 2.5 Flash
60%
Llama 3.3 70B
52%
Deepslate Opal
Competitor
tau2-telecom-bench.ai

Benchmark 02 · Model Intelligence

Built for complex CX scenarios.

The Tau2-Telecom Benchmark evaluates Voice AI models on tool calling, intent resolution, and end-to-end workflow completion in enterprise telecom contexts.

With a 71% accuracy rate, Opal outperforms Llama 3.3 70B, GPT-5.2, and Gemini 2.5 Flash in industry-specific tasks.

Benchmark 03 · Speech Reasoning

Direct audio understanding at the top of the field.

The Speech-to-Speech API processes speech natively, extracting nuance and complex context directly from the raw audio stream.

The Big Bench Audio test measures exactly that. Opal scores 90 out of 100, placing it at the top of the Voice AI benchmark leaderboard.

Big Bench Audio v2.1

Score (0–100) · Higher is better

AUDIO
Deepslate Opal
90
GPT-4o Audio
84
Gemini 2.5 Pro
81
Claude 3.7 Haiku
76
Whisper + GPT-4
71
ElevenLabs v2.5
63
Deepslate Opal
Competitor
bigbench-audio.github.io

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