A live audio spectrum analyzer captures sound from your microphone in real time and uses Fast Fourier Transform (FFT) to break the audio signal into its frequency components. It displays which frequencies are present and their relative amplitudes — essentially showing you the "frequency fingerprint" of the sound around you, updated many times per second.

FFT is an algorithm that converts a time-domain signal (the raw audio waveform) into its frequency-domain representation. It reveals how much energy is present at each frequency bin. The FFT size determines the frequency resolution: larger FFT sizes (e.g., 4096) provide finer frequency detail but respond more slowly to changes, while smaller sizes (e.g., 256) are faster but coarser.

This analyzer works by capturing live audio through your device's microphone using the Web Audio API and getUserMedia(). No audio is recorded, stored, or transmitted anywhere — all processing happens locally in your browser. The microphone permission is strictly required for real-time audio input. The tool cannot function without it.

Bars mode: Traditional vertical frequency bars — low frequencies on the left, high on the right. Bar height indicates amplitude. Circle mode: A radial/ polar spectrum display where frequency maps to angle and amplitude maps to radius from center. Wave mode: Shows the raw time-domain waveform, similar to an oscilloscope, letting you see the actual shape of the sound wave.

For general-purpose audio visualization, 1024 or 2048 offer a great balance between frequency resolution and time responsiveness. Use 256 or 512 if you want faster response to transient sounds. Use 4096 if you need precise frequency identification (like tuning an instrument), though it will feel slightly more sluggish.

Yes, to some extent. The peak frequency display shows the dominant frequency detected. For tuning, select a higher FFT size (2048 or 4096) for better frequency resolution, and play a single clear note. The tool will display the frequency and the closest musical note. However, for professional tuning, a dedicated instrument tuner may be more precise.

This tool requires a secure context (HTTPS or localhost) to access the microphone. Additionally, you must grant microphone permission when prompted by your browser. If you previously denied permission, you'll need to reset it in your browser's site settings. On iOS Safari, the first tap enables the AudioContext; try tapping Start twice if needed.

The typical human hearing range is approximately 20 Hz to 20,000 Hz (20 kHz). This analyzer covers the full range up to the Nyquist frequency (half the sample rate, typically ~22 kHz). Low-frequency sounds (20–250 Hz) include bass and kick drums; mid-range (250–4000 Hz) covers vocals and most instruments; high frequencies (4000–20000 Hz) include cymbals, sibilance, and harmonics.

Yes, the spectrum analyzer is fully responsive and works on iOS and Android devices via modern browsers (Chrome, Safari, Firefox, Edge). On mobile, the interface adapts to smaller screens, and the visualization remains smooth. Note that mobile Safari may require an explicit user gesture to activate the audio context.