After a piece has been partly or fully analysed the automatic facility may be used to detect the most likely tuning. This is the only parameter which requires a full re-analysis after it has been altered. All other parameters only require the piece to be re-filtered. Polyphony Not quite what is normally meant by polyphony. This is the number of new notes that can start at once.
Current notes can carry on playing.
When several notes are playing simultaneously, any notes with an amplitude lower than a percentage of the loudest current note will be filtered out. Neighbouring notes threshold When two adjacent notes are played then the amplitude of the weaker must be at least a certain percentage of that of the stronger, otherwise it is filtered out. This is mainly to help with low note recognition, where playing just one note produces a frequency spread of several notes during analysis. The amplitude of the weakest note saved in the midi file as a percentage of the loudest note in the whole piece. The frequency analysis does not lead to a smoothly decaying amplitude of each note because of the influence of other notes.