Rhythm Lab Help Center
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File Management

Rhythm Lab provides several means for sharing, exporting, importing, and saving files.

Custom Pattern Files

  1. Individual custom patterns that you create can be saved or exported in draft form for further editing, or for editing on another iPad. These patterns can be saved in JSON or RLDF format.
  2. Custom Pattern Sets can be saved for use on the current iPad, or exported for use on other iPads.
  3. Custom Pattern Sets can be exported to an external file storage location, sent by email, or uploaded to the Rhythm Lab website. Files on the Rhythm Lab website must be in JSON format. The links to these files can be shared and used as universal links – loading the pattern set into Rhythm Lab when the link is opened.
  4. Custom pattern sets can be imported using the “Import” item on the Custom Patterns menu of the Tap Screen, or opened directly from the Rhythm Lab website using the “Web” item on the Custom Patterns menu of the Tap Screen.
  5. Files in JSON format can be edited in a text editor, since JSON files are basically text files. See the JSON Files page for information on format and content requirements.


  1. You can import a MusicXML file into Rhythm Lab when you use the “Open” button on the Custom Screen. Simply choose a file that has been saved in MusicXML format (using .xml or .musicxml extension).
  2. Rhythm Lab will try to load the first eight measures of the first two voices or staves in the file. For example, if the MusicXML file was created using a grand staff, and there is one voice in the treble clefand one voice in the bass clef, Rhythm Lab will open the file as a Double pattern, treble staff voice on the top, bass staff voice on the bottom.
  3. The best way to use MusicXML files is to edit them in a standard music notation editor: Finale, Sibelius, Dorico, Notion, MuseScore, etc. and put the voices where you want them, with the number of measures that you want (maximum of eight). Otherwise, there is no guarantee that Rhythm Lab will present the contents to you in an acceptable form.
  4. MusicXML imports are limited to Single and Double patterns only. If you want to import a Single pattern, make sure that the MusicXML file has only one voice on one staff.

User Files

User files can be exported and imported in either JSON or RLUF formats. JSON is the recommended format, since it has wider recognition for apps that handle various file formats and extensions. RLUF format is available for users who want to create or save user files that are backward-compatible with older versions of Rhythm Lab.


Rhythm Lab uses the FluidR3_GM soundfont by default. You can use other soundfonts with Rhythm Lab. To load another soundfont, use the “Soundfonts” button in the Tap Options (settings gear) dialogue window. Rhythm Lab will load any .sf2 soundfont file, but only GM-compatible soundfonts with at least one drumkit (percussion) bank will work. Once a soundfont is loaded, you can select it as the current soundfont. Rhythm Lab will remove incompatible soundfonts and show an alert that it is incompatible.

There are many other sites on the web where you can find free soundfont downloads.

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