Use audioLevelUpdated

index.js

import _ from "lodash";

const speakingThreshold = 1000;
const notSpeakingThreshold = 2000;
const audioStream = {
  isTalking: false,
  timestamp: 0,
};

const onAudioLevel = function(event, elementId) {
    const now = new Date().getTime();
    if (event && event.audioLevel > 0.2) {
      // it could be speaking
      if (!audioStream.isTalking) {
        audioStream.isTalking = true;
        audioStream.timestamp = new Date().getTime();
      } else if (
        audioStream.isTalking &&
        now - audioStream.timestamp > speakingThreshold
      ) {
        audioStream.isTalking = true;
        audioStream.timestamp = new Date().getTime();
        // this means that it's speaking for more than X seconds
        // Call your UI function to update the active speaker
        updateActiveSpeakerEl(elementId, "add");
      }
    } else if (
      audioStream.isTalking &&
      now - audioStream.timestamp > notSpeakingThreshold
    ) {
      // low audio detected for X seconds
      audioStream.isTalking = false;
      updateActiveSpeakerEl(elementId, "remove");
    }
  };
}

subscriber.on("audioLevelUpdated", _.throttle((event) => onAudioLevel(event, subscriber.id), 50));