The Cockos Reaper digital audio workstation allows you to edit MP3 audio clips in a multi-track environment. Once you've imported MP3 files into Reaper, you can adjust their lengths, cut them into samples and apply audio effects to them. Reaper offers integrated support for the MP3 compression standard, meaning that it requires no additional audio plug-ins to import, work with and save MP3s. An unlimited 30-day trial version of the program is available.
Click "Track," then "Insert New Track."
Click "Insert" in the top menu bar, then click "Media File."
Navigate to the MP3 file you want to import into Reaper. Double-click the file to add it to the audio track. Repeat the process for any other MP3 files you want to import.
Reaper automatically aligns the start point of an imported MP3 with the end point of the previously imported audio file. Click and drag the MP3 waveform to rearrange them as needed.
Respect copyright limitations when sampling music or using audio clips.