"Voice Sonogram" is sound spectrogram app that expresses color intensity by frequency analysis of temporally continuous sounds. The sound spectrogram is used for acoustic analysis and voiceprint appraisal.

This app uses some sound analysis techniques such as FFT and Wavelet transform, and graphs the analysis results. It can be easily analyzed voices and instrument sounds, or you can learn elementary sound analysis.

Characteristic:
- Analyze the sound data recorded from the built-in microphone.
- FFT, Octave band analysis, and Wavelet transform can be selected.
- Analysis result graph and time axis sound waveform can be compared in playback.
- Snapshot: Save the analysis result in Photos.

Specification:
- Sampling frequency: 48kHz
- Recording time: Approximately 3 seconds
- Discrete Fourier transform: FFT (2048 points)
- Octave band analysis: 1/48 octave band
- Wavelet transform: Gabor Wavelet
- Graph display: vertical axis - time (0 - 3.0 sec), horizontal axis - frequency (100Hz - 8000Hz)

Note:
Wavelet transform (Tap "WV" button) has a large amount of calculation, so the processing load may be depending on the iPhone model, and it may take time to display the analysis result.