Adjust a microphone stand so the microphone collar sits approximately 3 inches away from and points toward the skin of the snare.
Connect the female end of an XLR cable to a microphone. Connect the other end of the XLR cable to the XLR jack on an audio interface. Slot the microphone into the microphone collar.
Connect the audio interface to your computer. The connection method varies depending on the make and model of the interface, but this typically calls for a USB or Firewire cable.
Launch your preferred digital audio workstation, such as Cubase or Pro Tools. Click "File" and select "New" to open a new session.
Open an audio channel from the file menu. Although you are recording to MIDI, the input type is audio, so this is the correct selection. Name the audio channel by double-clicking where it says "Audio 1."
Click on the audio channel to highlight it. This assigns subsequent commands to that channel specifically.
Open the "Plugins" menu in your digital audio workstation, select your preferred trigger plugin and click on it. A trigger plugin converts the audio signal into a trigger, which causes the digital audio workstation to record a MIDI event. The MIDI event contains note data, which is recorded, too. Trigger plugins are typically third-party software that come bundled with a digital audio workstation. Each workstation has a different selection of plugins. For example, Digital Performer includes the "MOTO" plugin for triggers.
Adjust the threshold in the plugin interface. The threshold determines the volume level that the audio must exceed in order to trigger the MIDI event. If you want every snare stroke to trigger a MIDI event, set it low. If you want only hardest strokes to trigger the MIDI, set it high.
Open a MIDI track from the "File" menu. Name this channel "Trigger Out." Click on it to highlight it.
Open the "Instruments" menu and select a sound. This is the sound that will record every time the snare exceeds the selected threshold. You can change this sound at any time before or after recording.
Click on the audio channel, select "Send To" and select "Trigger Out." This routes the audio from snare drum microphone to the MIDI channel.
Click the "R" icon on both channels to make them record-ready. Then hit "Record" when you are ready.