useGainNode

The blocks use this hook for every level control and bus: the microphone gain in Mic Setup, the soundboard's master bus, and the output of useSound.

$ pnpm dlx shadcn@latest add @audiocn/use-gain-node

UsageCopy Anchor Link

import { useGainNode } from "@/hooks/use-gain-node";
import { useMicrophone } from "@/hooks/use-microphone";
import { dbToGain } from "@/lib/audio/decibels";

export const MicMonitor = ({ gainDb }: { gainDb: number }) => {
  const microphone = useMicrophone({ enabled: true });
  // The microphone, through a gain stage, to the speakers.
  useGainNode({ gain: dbToGain(gainDb), input: microphone.stream });
  return null;
};

RoutingCopy Anchor Link

• input takes a MediaStream, which the hook wraps in a source node, or any AudioNode. Leave it out to feed the node yourself.
• destination is where the node plays. Leave it out for the speakers, pass null to route it yourself, or pass a node such as a mixer input or a MediaStreamAudioDestinationNode.
• The hook returns the node, so you can connect more to it, or pass it to useAudioAnalyser to meter the level after gain.

LevelsCopy Anchor Link

gain is linear: use dbToGain from @/lib/audio/decibels for decibels. Changes ramp with a short time constant (timeConstant, default 10 ms), so they never click. A new node starts at its gain instead of ramping up from unity, so a muted node is never heard as it starts.

Each connection lives in an effect and is undone on cleanup. That makes the node safe under StrictMode and <Activity>: hiding disconnects it, and showing reconnects it at the same level.