Sound Spectrum

Visualize sound from your Android's microphone.

Technical specification:

Recording

☆ Sample rate: 44100 Mono

☆ Chart buffer: 5 seconds

Decibel Level

☆ Reference pressure p0 = 20uPa

☆ decibel equation: 20 x Log10 (RMS/p0)

Frequency Spectrum

☆ Hanning Window

☆ FFT size: 4410 (100 ms)

☆ Overlapping: 80%

☆ Frequency: 1 Hz ~ 4 KHz over 64 groups

Credits:

☆JTransforms for FFT calculations. https://github.com/wendykierp/JTransforms