Check to use note velocities from MIDI file in interactive cluster notes. When using a MIDI instrument for input, you can choose whether you want to use the note velocities (hit strength, closely related to sound volume) as they are stored in the MIDI file or apply the velocity from the strength with which you actually strike the keys on your MIDI instrument. When using the PC keyboard, velocities always come from the file.

Check to use note durations from MIDI file in interactive cluster notes. You can choose whether you want to use the note durations as they are stored in the MIDI file or if you want to control this through the actual time you maintain the key pressed. In the last case all the notes of the cluster will be released at the same time, that is the time when you release the key which triggered the cluster.

Check to have the accompanying tracks (i.e. non interactive) follow your tempo skew (e.g. rubato)

Uncheck this box if a song's lyrics have been mistakenly stored as ordinary text events.

Redirection channel for unconstrained MIDI events sent from MIDI keyboard.

This is the time limit for consecutive notes to be considered as belonging to the same cluster. In other words, it is the maximum time gap between consecutive notes from which they will require 2 distinct keystrokes. With a small value, you might have to press a key several time to get e.g. a lengthy arpeggiated chord. On the opposite, with a large value, a series of 32nd notes may turn out to be played without user intervention. Default value of 100 ms is fine for most use. Still, experimenting with this value may help with relatively complex music pieces.

Since in One key hit per cluster mode, karaKB will play notes closer than this value at a single keystroke, you not only don't need to play the right notes, but you need only hit one key to play a complex chord. In this case the small time intervals between the notes of the chord are taken from the MIDI file, and altered according to the current tempo boost.