Working with loops in REAPER

Use this guide while working on Project 1: Arranging Clips . Set up the project once, then fit and check each loop before making copies.

• Set up the project
• Fit each loop with Option-drag
• Cut and glue a new phrase
• Repeat your phrase
• Check common problems

Set up the project

1. Choose a main loop and note its BPM on Looperman. Before importing audio, set REAPER’s project BPM to that value and use 4/4 for this exercise. Keep the transport’s playback rate at 1.0.
2. Open File > Project Settings. Set Timebase for items/envelopes/markers to Beats (position, length, rate).
3. Turn on snapping with the magnet button and turn on the metronome.

This timebase keeps items at the same musical positions and lengths if you later change the project BPM, stretching their audio to follow. Imported loops still need to fit the project tempo. Keep the BPM fixed while adding loops, and start with loops close to that tempo to avoid extreme stretching.

Fit each loop with Option-drag

1. Drop the loop onto its own track, with its first beat at the start of a measure.
2. Decide how many measures it should fill. Check its description or count the beats while listening. In 4/4, four beats make one measure.
3. Select the item, open Item properties from its right-click menu, and enable Preserve pitch when changing rate.
4. Hold Option on Mac or Alt on Windows and drag the item’s right edge to the intended measure boundary. A four-measure loop starting at measure 1 should end at the start of measure 5.
5. Listen with the metronome. Check that the loop stays in time through its final beat and ends at the expected boundary. If it already fits and sounds in time, leave it as it is.

Option-drag stretches the audio to fit. Dragging the edge without Option/Alt trims or repeats the item instead.

Cut and glue a new phrase

Use this step when you want to keep only part of a clip or combine pieces into one phrase. Fit loops from different tempos to the project before cutting and combining them.

1. Select a clip, place the edit cursor at the cut, and press S to split. Remove the pieces you do not want. You can also drag an item’s edge without Option/Alt to trim it.
2. Arrange the pieces you want to combine on the same track. Listen across the joins and fix unwanted gaps or overlaps.
3. Clear any time selection and select only the piece or pieces you want to glue. Right-click a selected item and choose Glue items.

Glue creates a new audio file and replaces the selected pieces with one item. You can now Option-drag its right edge to stretch the whole phrase together. Check Preserve pitch when changing rate on the glued item first.

You can also glue a single trimmed clip. This makes the trimmed section the new loop source, so repeating it does not bring back the unwanted audio. Glue keeps your edits, including gaps and overlaps; it does not correct their timing.

For example, place a two-measure section from one fitted loop immediately before a two-measure section from another. Glue both into one four-measure phrase. You can stretch the phrase as one item, keeping the join in proportion, or repeat it throughout your arrangement.

Repeat your phrase

Once the loop or glued phrase fits, duplicate it to build your arrangement. To repeat it by dragging, enable Loop source in Item properties and drag the right edge without Option/Alt. Listen across the repeat points with the metronome before filling the rest of the arrangement.

Check common problems

See the REAPER User Guide for more on project timebase, gluing items, and pitch/time manipulation.

Return to Project 1: Arranging Clips for requirements, submission instructions, and the rubric.