Audio Monitor

A web-based audio monitoring interface that allows users to route hardware audio inputs to outputs while providing real-time decibel level visualization. Built with vanilla JavaScript and Web Audio API, served via a lightweight Node.js HTTP server.

Features

• 🎤 Hardware Input Selection - Choose from available audio input devices
• 🔊 Hardware Output Selection - Select audio output devices
• 📊 Real-time Decibel Metering - Visual level meters for both input and output
• 🎛️ Volume Control - Adjustable output volume with live preview
• 🔴 Live Monitoring - Start/stop audio monitoring with visual feedback
• ⚡ Lightweight - No dependencies, pure vanilla JavaScript

Screenshot

Installation

Prerequisites

• Node.js (v14 or higher)
• A modern web browser with Web Audio API support

Setup Options

1. Use NPX:

npx audio-monitor

2. Install the package globally (optional):

npm install -g .
audio-monitor

Command Line Options

audio-monitor [options]

Options:
  --port, -p    Port to run the server on (default: 3000)
  --host, -h    Host to run the server on (default: localhost)
  --browser, -b Open the default browser to the server URL
  --help        Show help message

Usage Examples

# Start on default port 3000
npx audio-monitor

# When installed globally
audio-monitor

# Start on custom port and open browser
audio-monitor --port 8080 --browser

# Bind to all interfaces
audio-monitor --host 0.0.0.0 --port 3000

How to Use the Interface

1. Open the application in your web browser at http://localhost:3000 (default host/port)
2. Grant microphone permissions when prompted by your browser
3. Select an input device from the dropdown menu
4. Select an output device for audio playback or use system default
5. Click "Start Monitoring" to begin real-time audio monitoring
6. Adjust volume using the output volume slider
7. Monitor levels using the visual decibel meters
8. Click "Stop Monitoring" to end the session

Browser Compatibility

• Chrome/Edge (recommended)
• Firefox
• Safari (with some limitations)