What is the Ableton Pitch MIDI Effect?

The Pitch device transpose the MIDI notes sent to an instrument, resulting in a higher or lower part. This can be very handy in a variety of situations, such as finding the best key for a singer. Let's say you have a MIDI track playing a piano track. Just drop in a Pitch effect onto the track and dial in the new key.

The two values at the bottom of the Pitch device set the range of notes that can be used with the effect. If the bottom value, labeled Lowest, is set to C3, only MIDI notes C3 and higher will be allowed to enter the effect. The range value determines, by interval, the highest note that can enter the effect. So if the range is set to +12, notes C3 through C4 will enter the effect. Only after the incoming notes have passed the range test will they be transposed up or down. 

This situation may also arise when using patches on synthesizers that have splits. If you try to transpose the MIDI information out of the appropriate key zone, the synth will start playing the notes with the patch assigned to the other zones.