You may specify Fourier block size in samples, FFT window overlap percentage, spectrum's visual slope. SPAN provides you with a very flexible “mode” system which you can use to setup your spectrum analyzer preferences. SPAN is a free real-time “fast Fourier transform” audio spectrum analyzer AAX, AudioUnit, and VST plugin for professional sound and music production applications. RMS, true peak level, and clipping detector.Stereo, mid-side, surround spectrum analyzer.Fast Fourier transform spectrum analyzer.
