Instrument Plug-Ins : Boom : Boom Controls : Boom Setup Page

Boom Setup Page
Click the Setup button to view the Setup page. It has two parameters you can set that change Boom’s behavior.
 
Sync Mode
This sets the way Boom synchronizes with Pro Tools when patterns are triggered using MIDI notes. The modes are as follows:
Beat
Boom starts playing the selected pattern from the step that corresponds with the incoming MIDI note’s place in the current bar.
1/16
Boom starts playing the selected pattern from one of the first five steps in the pattern, corresponding with the incoming MIDI note’s place in the current quarter-note.
Notes played on the first or third quarter note of the current bar will trigger the current pattern from step 1. Notes played on the 2nd or 4th quarter note will trigger the pattern from step 5.
Off
Boom starts playing the selected pattern in sync whenever triggered by a MIDI note, without synchronizing to the Pro Tools transport.
Pattern Chaining On/Off
This lets you turn the Pattern Chain function on or off.