Grok voice is surprisingly good, actually. It's still a dumber model than the thinking modes of frontier models, but it's less dumb than the voice modes of other providers.

Yes the voice part of OpenAI realtime/voice mode is great but it’s pretty dumb compared to newer models and often gets stuck repeating itself.

Google’s Gemini flash live 3.1 is better, especially used via the API - it can do tool calling (including to other, even smarter LLMs if you set it up yourself), you can set the reasoning level (even high is still close enough to realtime) and it can ground answers in google search. I love bidirectional voice and right now it’s probably the best option. You can try it in AI studio

Claude voice mode has come a long way! I'd say it's smarter than CGPT AVM last time i tried it.

But personally I've settled on just speaking to the slower models over a custom tts app, I find it being instant was not actually that important, and in the silence I find myself marinating in the discussion more anyway

Yeah I was quite surprised that the advanced chat gpt voice mode can’t itself go and message the frontier model underneath to retrieve data and then speak it. I basically tried asking it for that (something like “can you go and ask gpt5.5 to research this more in depth, and while we wait, tell me about XYZ”), but apparently that’s not a thing.

You can feel what is possible using Gemini speech to speech model, it can do tool calls and is very fast. It lacks somewhat in thinking capability but you can setup a tool call to a smarter model and it acts as a relay. I’ve been very impressed.

This is what makes their voice mode unusable to me. I can’t stand the way 4o replies and it’s such a big jump in quality from text mode

Yeah, the question in the title can be answered: "by using gpt-4o, a model 2 years behind the frontier, to serve audio responses"