# Dynamic split in Reaper To quantize, open dynamic split with shortcut d, then [[How to quantize with Reaper]] and [[Fill gaps between selected items in Reaper]]. With dynamic split can split selected items, add stretch markers, or just create transient guides.^[ [Stretch Markers in REAPER](https://www.youtube.com/watch?v=rMg_3AI6MKo)] To quantize a multi-mic setup like drums, group items first (g). Then you can split or add stretch markers to grouped items. When quantizing, make sure to click "Move grouped items with selected item."^[ [Drum Editing without Stretch Markers in REAPER](https://www.youtube.com/watch?v=8bCnk5kPkKA)] [[How to mask time edits]]