Audio Spectrum Analyzer that measure audio frequency response in real time. Data is measured through built-in smartphone's microphone. Features: Sample rate: 8000 and 44100. FFT length: 512, 1024, 2048, 4096 and 8192. Averaging: 1, 2, 4, 8, 16 and 32. Single finger axis re-position. Dual finger pinch zoom. /- 20 dB SPL calibration.