Exercise 9

Exercise 9: Buffer Recording and Playing

Many pieces for solo instrument or voice and electronics feature live input from a microphone picking up the sound of the soloist. This allows the software to provide real-time effects and also makes it possible to record parts of the performance for playback during the piece.


We’re learning how to...

  • take live input from a microphone,
  • record this sound into a buffer, and
  • play back the sound.

How to Do This Exercise

Working on the assignment is a two-stage process.

  1. Download Exercise 9 Max Tips. This folder of Max patches shows you how to access live input, explains the concept of a buffer, and tells you how to record sound into a buffer and play it back.
  2. Make a patch that records sound from a mic into a buffer and then plays it.

See the Requirements and Suggestions section below for details. The Max Tips patches explain the required techniques.

Be sure you understand what each of these Max objects does:

  • ezadc~
  • buffer~
  • waveform~
  • play~, groove~
  • record~
  • loadmess

Requirements and Suggestions

  • Set up your patch to receive input from a microphone. Use an ezadc~ object for this. Patch a live.gain~ or meter~ after the ezadc~, so that you can detect clipping on the meter. Control the level of the mic signal from outside of Max: at the sound input control panel for your system or a mic preamp trim knob, if you have an audio interface or hardware mixer. Use the meter to determine the right input level.
  • Create a buffer~ object that holds three seconds of sound, and set up your patch to record the mic into this buffer using the record~ object.
  • Play the contents of the recorded buffer~ using either the play~ or the groove~ object. Set up your patch so that you can play the buffer using a few different speeds.

    The essential difference between play~ and groove~ is that with play~, you specify how the playback “cursor” moves across the buffer, whereas with groove~, you specify a playback rate.


  • Be sure you satisfied the criteria listed above.
  • Submit your Max patch in Canvas.

Grading Criteria

This exercise is graded pass/fail. You must submit the exercise by Thursday midnight to be eligible for a pass.

Your patch must

  • operate correctly and
  • implement the functionality described in the “How To Do This Exercise” section above.