Signalizer is described as 'all-in-one signal visualizing package with a bunch of unique focus-points; real-time audio visualization with optimized 3D GPU graphics, everything being scalable and zoomable gridlessly as well as being arbitrarily precise in both settings and display'. There are more than 10 alternatives to Signalizer for Windows, Linux, Android and Mac. The best alternative is Friture, which is both free and Open Source. Other great apps like Signalizer are Spectroid (Free), Scope (Free Personal), Visual Analyser (Free) and xoscope (Free, Open Source).
Real-time audio spectrum analyzer with reasonable frequency resolution across the the entire frequency spectrum. - Spectrum - Waterfall - Max-hold trace - Peak markers - Linear or logarithmic frequency scale
TrueRTA's audio spectrum analyzer software shows you a detailed picture of what you're hearing in real-time, that is, as it happens. You can create your own professional measurement system starting with TrueRTA software on your PC.
iSpectrum is an easy to use audio spectrum analyzer that allows you to view live audio in a standard frequency plot, a stereo oscilloscope view and a waterfall display. You can adjust the display resolution, center frequency and save images to disk.