AudioExplorer is a set of tools for interactive analysis of audio

AudioExplorer's functions include:

• The Audio Window, providing simultaneous and integrated views of the audio waveform, pitch analysis, and the Note Map, a high-resolution image of the musical content.
• A polyphonic MIDI generator, functioning both in real-time during playback/record, and in batch mode for more precise control of the audio-to-MIDI conversion process.
• A dynamically generated Note Map, allowing you to visually examine musical events resolved in time and pitch.
• A Frequency Map, an image similar to the Note Map, but providing greater frequency resolution.
• The ability to examine the activity of individual notes through any time interval of the audio file.
• Various views on the spectral content of an audio file.
• Highly customizable displays.

Have a look here for an overview of AudioExplorer's signal processing.

For a detailed look inside AudioExplorer, have a look at its Help files. [Note: because the help pages are written for local browsing, some pages may be slow to download, depending on you connection speed].