Frequency analyser
Press Start listening and allow the microphone to see which pitches are loudest.
The loudest pitch
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Nothing heard yet.
Phone and laptop microphones hear little below about 50 Hz, the shaded strip, so a very deep hum may barely show.
Technical details
- peak
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- note
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- sample rate
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- FFT size
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- resolution
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- window
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- processing
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The microphone is opened with echo cancellation, noise suppression and automatic volume turned off, so the browser does not reshape the sound; the line above says what it actually agreed to. Each picture is a Fourier transform (FFT) of the latest samples through a Blackman window. A bigger FFT separates close pitches better but covers a longer stretch of time, so it reacts more slowly. The peak is refined between FFT steps by fitting a parabola through the loudest three, which makes it far more precise than one step. Levels are dB below the loudest sound the microphone can record (dBFS), not sound pressure, so they compare sounds rather than measure them. The note is named against A4 = 440 Hz, and a cent is a hundredth of a semitone.