When programming keyboard books, you’ll sometimes encounter a sound effect that needs to be mapped to a specific key. The best way to do this in MainStage is to create an EXS24 instrument for your sound effect(s). First, let’s go through some basic terminology.

EXS24 is a sampler plugin that works within MainStage. A sampler lets you manipulate audio samples and assign them to specific keys so they can be triggered by a keyboard or some other MIDI controller. In EXS24, samples are assigned to zones. Only one sample can occupy a zone, but a zone can stretch across multiple keys. You can also put any number of zones inside a group, which acts as a folder with its own customizable parameters.

Before continuing on, be sure your sound effect sample meets the following criteria.

  • The sample is in 16 bit/44.1 kHz WAV or AIFF format.
  • Excess silence before or after the sample has been edited out.

If you don’t have a sound editor, Audacity is a great program and can be downloaded for free. Below is a comparison of an unedited sample and an edited one.

Before proceeding on with the rest of the tutorial, I recommend you create a folder in your “Sampler Instruments” folder for your sound effects. That way, they’ll always be in a safe place. Open Finder, press “Cmd+Shift+G,” and type the following: “/Library/Application Support/Logic/Sampler Instruments,” This will bring you to the right folder.

Now, it’s time to map the sound effect to a key with a custom EXS24 instrument.

  • Open up an instance of EXS24, and hit “Edit” to bring up the Instrument Editor window.
  • Click on “Zone”, and create a new zone.
  • Click on the triangle to the right of “Audio File”, and navigate to the sound effect.
  • Under “Playback”, make sure only “1shot” is checked. “Pitch” and “Reverse” should be unchecked. “1shot” plays through the whole audio file without having to hold down a key, “Pitch” pitch corrects audio files, and “Reverse” plays audio files in reverse.
  • Save the instrument in the same directory as your sound effect audio file.
  • In EXS24’s instrument interface, turn “Level” up to full in the top right corner. This will turn off velocity sensitivity, and your sound effect will always sound at full volume.

Now you have an EXS24 instrument that triggers your sound effect when any key is pressed. Notice that we didn’t map the sound effect to a specific key range inside EXS24. The better solution is to use MainStage’s Layer Editor to map the instrument to the correct key. This way, you can assign the sound effect to any key without dealing with EXS24’s interface. In addition to sound effects, this method can also be used to trigger sequenced harp glissandi.