Frequency Spectrum
Click "Start Mic" to begin analysis
Peak Frequency
—
Peak Level
—
0 Hz5 kHz10 kHz15 kHz20 kHz
About
The Frequency Analyzer displays a live Fast Fourier Transform (FFT) spectrum of the audio captured by your microphone. It is useful for identifying dominant frequencies in a room, checking speaker frequency response, analysing acoustic environments, or just visualising music and voice in real time. The dB range is adjustable to focus on the frequency bands you care about.
How to use
- 1 Click Start Mic and allow microphone access in your browser.
- 2 Play audio, speak, or generate tones — the spectrum updates in real time.
- 3 The peak frequency and level are shown above the spectrum.
- 4 Adjust the dB Min / Max dropdowns to zoom in on the dynamic range.
- 5 Click Stop to release the microphone.
- What is an FFT spectrum analyzer?
- FFT (Fast Fourier Transform) is a mathematical algorithm that decomposes an audio signal into its constituent frequencies. The spectrum analyzer applies FFT to your microphone input in real time and plots the result as a bar graph where the X axis is frequency (20 Hz to 20 kHz) and the Y axis is amplitude in decibels (dB). Peaks in the spectrum show which frequencies are dominant in the sound.
- What practical uses does a frequency analyzer have?
- Common uses include: identifying hum or resonance in a room (often 50 or 60 Hz from electrical interference); checking if a speaker or headphone has a flat frequency response; finding feedback frequencies when setting up a PA system; analysing the harmonic content of musical instruments; and verifying that audio equipment is processing sound as expected.
- What does the dB level on the spectrum mean?
- The dB (decibel) level shows the amplitude of each frequency component relative to full scale (0 dBFS). A value of 0 dB means the signal is at maximum amplitude; -60 dB is very quiet; -120 dB is near the noise floor. Adjusting the dB Min/Max range zooms the display vertically — use a narrower range (e.g. -60 to 0 dB) to see subtle details in loud signals.