Free online spectrum analyzer and spectrogram for audio files and microphone input. Measure frequency, dBFS, peaks, and export PNG or CSV locally in your browser.
OnlineSpectrumAnalyzer.com is a really handy browser-based tool for visualizing audio frequencies in real time. I especially like that you can analyze both microphone input and uploaded audio without installing any software. The spectrum and spectrogram views make it useful for quick audio analysis and experimentation.