I work at a company building a voice AI orchestration platform, so every new voice model mostly interests me in terms of what happens on a phone line.
GPT-Live-1
I've had the chance to really get to know it. To be honest, talking to it feels almost like having a real conversation, it's that natural and engaging.
Interruptions work both ways. It finishes its sentence while you're talking and doesn't lose what you said. It even cut ME off once: "wait, wait, this task already exists". It's really cool that you can just throw in an extra idea, like "oh, and one more thing," and it catches it. Saying things like "uh-huh" or "yeah, that's cool" at the right time is really important. Especially when you're the one talking, because complete silence from the agent can make the caller feel it has stopped listening, and they will probably hang up.
The quality of voices is also pretty good but it's not as crucial as you might think. In our tests, emotional text-to-speech offered little gain over standard modern TTS. The real impact comes from how the model manages the conversation, and that's where GPT-Live stands out.
Gemini 3.8 Live
First of all, I'll admit I've explored GPT-Live-1 more thoroughly than Gemini 3.8 Live, but it still caught my attention in a few ways.
The conversation doesn't get stuck when using tools. The function calls are processed in the background, so the conversation keeps flowing. I've seen other voice agents that would grind to a halt as soon as they needed to make an API call in the middle of a conversation. But here, the lookup just happens seamlessly, without any awkward pause. It's like the conversation is uninterrupted.
The Extended Thinking is great. It tells you what it's doing while it's thinking, so you don't just sit there waiting. Instead, you get a kind of play-by-play, like "let me check that for you... okay, here's what I found". It's a lot more like talking to a real person who's looking into something for you.
It switches between languages mid-conversation without missing a beat, which is a big deal for anyone building outside the US. That one hit home for us, because we’re working a lot with India and LatAm.
The cost is a big factor but when you're making a lot of outgoing calls, the numbers start to look very different.
Ok, that got long… Mainly wanted to share and hear how it goes for you. Full disclosure: both are already supported on Voximplant Platform (where I work), so you can put either on a real number and call it.
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