Spectralissime is described as 'High Definition Frequency Analyzer For Any Acoustic Measures by V.Burel' and is an app. There are eight alternatives to Spectralissime for Windows, Mac, Android and Linux. The best alternative is Friture, which is both free and Open Source. Other great apps like Spectralissime are Spectroid, Sonic Atom, Visual Analyser and WaveSpectra.
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.