Requires microphone access. Audio is analyzed locally in your browser - nothing is recorded or uploaded. Browser echo cancellation and noise suppression are disabled for a truthful spectrum.
Hunt down hums
A persistent spike at 50 or 60 Hz is mains hum; at 100/120 Hz, its first harmonic - usually a ground loop or transformer. Broadband low rumble points at HVAC or traffic. The peak readout names the frequency for you.
Verify test signals
Play a tone from our tone generator on another device and confirm the spike lands at the expected frequency - or run pink noise through speakers and eyeball the room's response shape.
See voices & instruments
Sing or play a note: the tallest low spike is the fundamental, the evenly spaced spikes above it are harmonics - the recipe that makes your voice yours. Whistle for the purest single spike you can produce.
Spectrum Analyzer FAQ
What does a spectrum analyzer show?
It splits incoming sound into its frequency components and displays how much energy is present at each frequency, updated many times per second. A pure tone shows as a single spike; a voice shows a fundamental plus harmonics; noise shows a broad wash. The height of each bar is relative level in that frequency band.
Why does the analyzer need my microphone?
The analyzer visualizes real sound from the room, which requires microphone access. Everything runs locally in your browser using the Web Audio API - no audio is recorded, stored, or sent anywhere, and access stops the moment you press Stop or leave the page.
How accurate is a browser spectrum analyzer?
Frequency readout is accurate to within a few hertz (limited by FFT resolution, about 23 Hz per bin at the default settings). Absolute level is not calibrated - your microphone, its position, and browser processing all shape it - so treat levels as relative. For frequency identification (finding a hum, checking a tone, spotting harmonics) it is genuinely reliable.
What can I use a spectrum analyzer for?
Identifying mystery noises (a 50/60 Hz spike means mains hum, 100/120 Hz its harmonic), checking what frequencies dominate a room, verifying a test tone is playing at the right frequency, watching your voice or instrument harmonics, and roughly assessing speaker output across the band when playing pink noise or a sweep through them.
Why do I see activity even when the room is silent?
Microphone self-noise and room ambience never reach zero, and browsers may apply automatic gain that amplifies quiet backgrounds. A low broadband floor is normal. Distinct persistent spikes in a "silent" room are real signals worth investigating - commonly HVAC rumble at low frequencies or electronic whine higher up.