Loop Source

From CockosWiki

Something that seems to confuse newcomers to Reaper (definitively me, and others http://forum.cockos.com/showthread.php?t=29105) is the possibility to Loop Source. When this is on, Reaper replays the source from beginning again and again. In the picture you can see the difference of the same media item looped (track 1) and not looped (track 2). The small "chops" show where the original source ends and a new "loop" begins. You can drag edit either end of the media item to get the number of loops you need.

Loop Source is set in the Media Item Properties (right click a media item, select Item properties..., it can also be set under Item settings, see below), and it is on by default. The song Making Me Nervous by Brad Sucks (that used to come bundled with Reaper, is now available here http://stash.reaper.fm/4200/BradSucks_MakingMeNervous.zip) makes extensive use of Loop Source. Review it to see how you can use Loop Source to your benefit. Basically, if you have repeating stuff, just record it once and loop it.

Sometimes you have a media item of which you want to loop only a part. This is possible by using the Loop section of item command that you find under Item settings.... The picture below shows this. The top item (Track 1) is the original item. Note that it has silence in the beginning and at the end, that we want to exclude when looping. To get Reaper to loop only the interesting part, slip-edit the item to the interesting part, as in Track 3, and select Loop section of item. Now, when you loop source, you will get what is shown on Track 2; only the interesting section is looped.