Input to Audio Spectrum Analyzer from microphone or wave file. Audio Spectrum Analyzer has variable displays, Fast Fourier Transform (FFT) display, variable sample rates (8000 Hz, 11025 Hz, 22050 Hz, and 44100 Hz), variable transform sizes (1k, 2k, 4k, and 8k), adjustable upper and lower limits, continuous, averaged, and peak hold, selectable foreground and backgrounds, variable markers, option to save a reference plot compare with the foreground plot, time display (oscilloscope), triggered sweep, and waterfall display (color or B/W).