> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ai-coustics.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Quail Voice Focus

> Primary-speaker isolation for speech-to-text and voice agents.

**Quail Voice Focus** targets one primary speaker while suppressing competing speech, background noise and residual echo. Use it when a voice agent should follow one participant, rather than transcribe every voice in a room.

Voice Focus uses recent audio context to select the primary speaker. At the beginning of a stream, suppression can be weaker while that context builds. Test startup with short utterances and quiet speakers; there is no fixed warm-up duration guaranteed by this guide. Keep processing continuous across adjacent frames so the model can retain context.

Primary-speaker selection can change when another speaker becomes more prominent, such as when someone moves closer to the microphone. It is not a persistent identity lock. If your application requires identity verification or a fixed enrolled speaker, model selection alone does not establish that behavior.

## Choose a variant

For core SDK 0.25.0, start with `quail-vf-2.2-l-16khz` or compare the smaller `quail-vf-2.2-s-16khz` on your target hardware. Both have a native rate of 16 kHz and an optimal native block size of 240 samples. See the [model reference](/reference/sdk/models#quail-voice-focus) for acquisition and compatibility.

## Check speech retention

Compare original and enhanced recordings using your speech-to-text (STT) provider. Include quiet target speech, overlapping speech, speaker changes and the first seconds after a reset. Measure target-word deletions as well as background-word insertions; stronger suppression can remove speech you intended to retain.

For dedicated ai-coustics voice activity detection (VAD), use the original input audio. [VAD Voice Focus](/models/voice-activity-detection/vad-voice-focus) targets primary-speaker activity when only the target speaker should drive speech activity. A third-party VAD may behave differently on enhanced audio; evaluate its speech boundaries and added delay separately.

Follow [Voice Focus tuning](/models/voice-focus/voice-focus-for-voice-ai-systems) and the [SDK quickstart](/models/get-started/sdk-quickstart) for the next step.


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