Glossary · AI & Agents
Latency Tuning
Overview
What it is
Latency tuning is optimizing an AI voice agent so it replies fast enough to feel like a real conversation. End-to-end (or "voice-to-voice") latency is the total time from the caller stopping speaking to hearing the agent respond.
Humans expect a reply within a few hundred milliseconds; past about one second a call feels laggy and people talk over the agent. Tuning targets that budget.
How it works
Latency accumulates across the pipeline: speech-to-text, the LLM's time-to-first-token, text-to-speech, plus telephony and network hops. Tuning attacks each — streaming partial transcripts and audio, using faster or realtime models, trimming prompt size, colocating services, and handling turn-taking and interruptions well.
Realtime APIs and low-latency STT/TTS vendors (e.g. Deepgram, Cartesia, ElevenLabs) and platforms like LiveKit or Pipecat are chosen partly for the latency they add.
Why it matters
Latency is one of the biggest reasons AI phone calls feel robotic or frustrating. Getting voice-to-voice latency under about a second is often the difference between an agent callers tolerate and one they trust.
We tune the whole stack — model choice, streaming, and routing — so our voice agents hold natural, low-lag conversations.
Where we use it
Related Zen in Tech services
How our team puts Latency Tuning to work in real projects.
FAQ
Latency Tuning — common questions
What is a good latency for an AI voice agent?
Aim for end-to-end (voice-to-voice) latency under about one second, with sub-500ms feeling most natural. Above ~1s, callers start to talk over the agent and the conversation feels laggy.
What causes latency in AI voice agents?
It adds up across speech-to-text, the language model's response time, text-to-speech, and telephony/network hops. The LLM's time-to-first-token and non-streaming stages are usually the biggest contributors.
How do you reduce voice AI latency?
Stream partial transcripts and audio instead of waiting for full turns, use faster or realtime models, keep prompts lean, pick low-latency STT/TTS vendors, and colocate services to cut network hops. Good turn-taking and interruption handling also help.
Need Latency Tuning done right?
Book a free consultation and we’ll map the fastest, most cost-effective path for your project.
Knowledge hub
From our knowledge hub
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