Live Audio Visualizer
Visualize your microphone audio as a live frequency spectrum using the Web Audio AnalyserNode. Nothing is uploaded.
Pure browser JavaScript — uses getUserMedia, the Web Audio AnalyserNode, and Canvas.
How to use this tool
- Click Start visualizer and allow microphone access.
- Play music or speak — the bars show the live frequency spectrum.
- Click Stop to end the visualizer and release the microphone.
Visualize your microphone audio as a live frequency spectrum using the Web Audio AnalyserNode. Nothing is uploaded.
How it works
The Live Audio Visualizer captures audio from your microphone using the Web Audio API and feeds it through an AnalyserNode, which performs a Fast Fourier Transform (FFT) on the incoming signal many times per second. The result is a real-time frequency spectrum showing which pitches and harmonics are present in the sound at any moment.
The horizontal axis represents frequency (from low bass on the left to high treble on the right) while the vertical axis shows amplitude -- how loud each frequency band is. This lets you see, for example, that a bass drum hit produces a spike on the left while a whistle appears on the right.
Nothing is recorded or uploaded. Audio is captured only while the page is open and active. This tool is useful for audio education, checking microphone response, troubleshooting sound equipment, or simply as an interactive visual while playing music.
Worked example
Check your microphone frequency response
- Open the tool and grant microphone permission when prompted.
- Speak at a normal volume and watch the lower-frequency bars rise.
- Whistle a high note and observe the spike shift toward the right side of the spectrum.
- Clap once and notice the broad burst of energy across many frequency bands.
A visual confirmation that your microphone is picking up a realistic range of frequencies.
Common mistakes to avoid
- Using the tool in a noisy environment and expecting clean results -- background noise fills the spectrum and makes it hard to isolate a single source.
- Forgetting to grant microphone permission, leaving the display static or empty.
- Expecting the tool to record or export audio -- it is a real-time visualizer only.
Key terms
- FFT (Fast Fourier Transform)
- A mathematical algorithm that converts a time-domain audio signal into its component frequencies, enabling real-time spectrum analysis.
- AnalyserNode
- A Web Audio API node that exposes frequency and time-domain data from an audio stream without altering the signal.
- Frequency spectrum
- A display of audio energy across the range of audible frequencies, typically 20 Hz to 20 kHz.
Frequently asked questions
- What do the bars represent?
- Each bar is a frequency band from the AnalyserNode's FFT, with height proportional to that band's current loudness.
- Is the audio recorded?
- No — it is analysed in real time and discarded. Nothing is stored or uploaded.