The tracks on your MPC each feature their own input monitoring button which switches between three states when tapped: In, Auto, and Merge.
The input monitoring buttons for all tracks can be found by pressing the Menu button and selecting Track View. Please see the image below, where the input monitoring buttons have been marked in yellow...
When set to IN: the audio of your connected instrument will be heard before it reaches the MPC. This is similar to direct monitoring, whereby you only hear a live feed of your instrument signal to ensure zero latency. After you have finished recording audio, you will not be able to hear the recording played back when monitoring is set to IN; you will only be able to hear the live feed of your instrument.
When set to AUTO: you will hear incoming audio while the track is record-armed only, and you will be able to hear your audio recording being played back afterwards when the play button is pushed. This is the most commonly used setting.
When set to MERGE: You will be able to hear the input signal of multiple record-armed tracks at the same time. All of the tracks that you want to hear will need to be set to MERGE with their record buttons armed.
To record arm multiple tracks at the same time, simply hold the shift button while tapping each record arm button.
