What happened this week
Full-duplex models listen and speak at the same time, the way a phone call works and a walkie-talkie does not. Two new benchmarks scored them action by action and found the same split. The models stay quiet or yield well, and do poorly when they have to time an entry themselves: a backchannel (the short "mm-hm" a listener gives without taking the turn) or an interruption.
Benchmarks
DuplexAct, from the University of Melbourne, the University of Birmingham and Wuhan University, defines eight interaction actions under 24 conditions and tests 14 models on 4,691 instances, 2,531 of them taken from real recordings. Each action is scored at the moment it was due and again on follow-through. Backchannel success at the moment it was due is near zero almost everywhere. Raon-SpeechChat, trained with a dedicated backchannel token, leads at 31.0%; GPT-Realtime-2.1 scores 0.2%. When the right move is to interrupt, Moshi succeeds 67.5% of the time, GPT-Realtime-2.1 8.8% and Grok Voice 0.0%. The four closed models enter the floor correctly 77.7 to 97.0% of the time on Recover but only 27.5 to 41.3% on Take Turn, so skill at one entry action does not predict skill at another.
MultiPartyTurnBench, from the University of Maryland, moves turn-taking from two speakers to two to five. Its 240 synthetic conversations keep each speaker on a separate channel, so every turn end and every takeover has an exact timestamp. End-of-turn detectors reach 82.5 to 92.6% recall at 4.3 to 11.8% false-positive rates, while interruption detection either misses takeovers or fires too often. Five full-duplex agents reach 86.1 to 95.8% balanced accuracy on entering the floor and 46.9 to 54.7%, near chance, on selective interruption: stopping for a real takeover and not for other overlapping speech. Gemini-3.8-Live yields to 97.7% of backchannels; MiniCPM-o-4.5 yields to only 1.4% of genuine interruptions. The benchmark takes its interaction types and event-matching protocol from TurnBench, scores a TurnBench development slice, and uses two baseline checkpoints the paper attributes to oto. Fullduplex is published by oto, which supplied TurnBench's training split and has co-authors on the TurnBench paper.
For a product team, a high turn-taking score says little about barge-in or backchannels, so test those on your own calls.
Building full-duplex models
D2, from MIT CSAIL and the MIT-IBM Watson AI Lab, starts from half-duplex spoken language models, which wait for the user to finish, and converts them. It distills the audio encoder into a streaming one, then fine-tunes on full-duplex dialogue. At a 12.5 Hz update rate, Qwen3-Omni-D2 reports 99.2% turn-taking success at 521 ms latency, 99.5% interruption success and a VoiceBench score of 70.1, which the authors call state of the art. A team could keep the general capability of a strong half-duplex model without training a full-duplex one from scratch. A demo page is up; no code or weights are announced.
Jarvis, from CUHK-Shenzhen, Tencent Hunyuan and Amphion, handles the case where a realtime front model hands slow work to a background agent and the user changes the request mid-task. Jarvis adds a separate decision model that reads each new utterance against a versioned task record, while code rejects any action on a version the user has already replaced. With the front model and back end held fixed, swapping Qwen Audio Agent for Jarvis raises tau-Voice task success from 29 to 192 of 278 tasks. On Full-Duplex-Bench v3 it reports 69% Pass@1 with an open 9B front model, against 60% for GPT-Realtime.
On the half-duplex side, VoxTurn, a single-author report from the University of Melbourne, answers several turn-taking questions, including end-of-turn and interruption-or-backchannel, in one forward pass of a 0.8B model. It reports 11.5% English false cut-offs at a 300 ms budget on eot-bench and ranks fifth of 24 in TurnBench end-of-turn detection without TurnBench training data. Fullduplex is published by oto, which supplied TurnBench's training split.
Models and platforms
xAI released Grok Voice 3.0 on October 14. Citing Artificial Analysis figures from October 13, xAI reports a Speech-to-Speech Index score of 86.9 against 83.2 for GPT-Live-1 and 82.6 for Gemini 3.8 Live, 97.0% on Full Duplex Bench, and 71.6% on tau-Voice at what it calls 40% lower latency than GPT-Live-1, which scores 74.5% there. The price stays at $0.08 per minute.
OpenAI made prompt-to-voice available to all API customers on October 16: a developer describes a voice in text and saves it for GPT-Live sessions. Creating the voice is free; speech is billed at GPT-Live rates. It also added nine GPT-Live voices in German, French, Hindi, Japanese and Korean, and on October 15 let GPT-Live call its Decisions feature while the user is still speaking. LiveKit Agents 1.8.8 (October 15) now runs GPT-Live through LiveKit Inference as a DuplexModel.
Sarvam released Bulbul V4 Flash on October 13, a text-to-speech (TTS) model for Indian-language voice agents. Sarvam reports under 250 ms to first audio in production and up to 40% faster than V3, with 83 voices across 11 languages, at ₹20 per 10,000 characters against ₹30 for V3.
New on Hugging Face, tyger from nineninesix is an open speech decision model for full-duplex agents. It reads the user's microphone and the agent's own playback as two streams and, every 80 ms, outputs listen, hold, speak or backchannel. It is a 14M-parameter recurrent head on an unchanged NVIDIA Nemotron 3.5 streaming recognizer (ASR, automatic speech recognition). On the Open Yap 1K test set it reports a 252.5 ms median endpoint latency with 29.90% early cut-ins, and catches 25.32% of barge-ins within 640 ms. The card calls these offline diagnostics from one training seed. ElevenLabs also added a turn_prediction commit strategy to its realtime speech-to-text on October 12, which closes a segment when its model predicts the speaker has finished.
The rest of Hugging Face this week was mostly small English on-device ASR and TTS built on Parakeet and Kokoro, a few Chinese dialect, Korean and Turkish releases, and mostly permissive licences.