Artificial Analysis (@ArtificialAnlys) published its Speech to Speech Index: OpenAI GPT-Live-1 with Astra (medium) as the delegated backend debuts at #1 with 81.5, while Sol (low) scores 80.1 at #3, with Grok Voice Think Fast 2.0 High between them at 81.3. GPT-Live-1 is a full-duplex speech model that can delegate reasoning and tool use to a backend text model mid-conversation. The same drop covers Speech Agent Arena, Tau Voice, Big Bench Audio, plus cost and time-to-first-audio.

Key Takeaways

  • βœ“GPT-Live-1 (Astra medium) leads Speech to Speech Index at 81.5; Sol low is #3 at 80.1.
  • βœ“On Tau Voice, Astra medium (67.9%) and Sol low (59.3%) take the top two agentic spots.
  • βœ“Cost is about $5.83/$4.47 per hour of input audio incl. backend; TTFA about 1.34s/1.24s vs Grok Voice 0.70s.
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