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Known Issues and Troubleshooting

1. Issue: Composer fails to load your Reaper project (the analysis bar does not appear).​

Cause 1:​

This issue often occurs when a Performer track in Reaper hosts a VST3 plugin but lacks MIDI data. Composer will not import the project, even if MIDI data is routed to it from another Performer track.

  • Solution: Ensure that each Performer track hosting a VST3 plugin contains MIDI data before importing the project into Composer.

Cause 2:​

Similarly, routing a Performer with no MIDI data to another Performer containing a VST3 can prevent the project from importing altogether.

  • Solution: Ensure that all Performer tracks involved in routing contain MIDI data before attempting to import the project into Composer.

Cause 3:​

The presence of a very small MIDI item at the beginning of the Reaper timeline, which is often barely visible even when zoomed in. This can be identified by a tiny white vertical line (see example below).

Tiny MIDI item

  • Solution: Locate and delete the small MIDI item at the beginning of the timeline.

2. Issue: Some Performers are silent, have omitted notes, or aren't parsed correctly by Composer.​

Cause 1:​

Using built-in arpeggiators or sequencers in VST instruments.

  • Solution 1a: Ensure that every sound event in Reaper corresponds directly to a specific MIDI note. Avoid using built-in sequencing features and manually program each MIDI note to trigger the desired sounds.

Cause 2:​

Using a VST (or Audio Unit etc.) instead of a VST3.

  • Solution 2a: Double-check that you are only using VST3 plugins.

Cause 3:​

Messy MIDI data, such as takes and overlapping items, can cause parsing issues.

  • Solution 3a: Regularly glue MIDI items to keep them tidy and avoid overlaps.
  • Solution 3b: Ensure that MIDI takes are consolidated and cleaned up to prevent any conflicts or errors during parsing.
  • Solution 3c: Review and simplify the MIDI data structure to maintain clarity and organization within your project.

Example: Messy MIDI data Messy MIDI data

Example: Tidy MIDI data Tidy MIDI data

Cause 4:​

Routing instabilities.

  • Solution 4a: Instead of routing, try duplicating the VST3 plugin to see if it resolves the issue.
  • Solution 4b: Ensure that all Performers are ordered at the top of your Reaper session and all Stingers at the bottom. This may stabilize routing and parsing issues.

Cause 5:​

Using effects plugins (such as EQ or compression) in oversampling or high-quality mode.

  • Solution 5a: When using effects plugins, ensure they are not in oversampling mode. Use them in low-CPU/low-latency mode instead.

Cause 6:​

Using audio tracks instead of MIDI.

  • Solution 6a: The use of audio tracks is neither implemented nor recommended in Composer. If you want to use specific sounds such as SFX, load them into a drum sampler and trigger them via MIDI instead.

3. Issue: Composer encounters an error while sampling a Performer track: "Cannot set properties of undefined (setting 'Polyphony'). Performers using this VST will be silent."​

Cause:​

The error is likely caused by having two identically named performers (e.g., two instances of "Performer: Violas") in the Reaper file. This may be triggering the "polyphony" error message.

  • Solution: Rename the performers to unique names, such as "Performer: Violas 1" and "Performer: Violas 2."

4. Issue: Error message: "This file format is not supported."​

Cause:​

You may be attempting to import an .rpp-bak (Reaper backup) file instead of the .rpp (Reaper session) file.

  • Solution: Double-check that you are importing the .rpp file (Reaper session) and not the .rpp-bak (Reaper backup) file.

5. Issue: Music sounds different in Composer compared to in Reaper.​

Cause:​

It is normal for your music to sound slightly different after import due to the way Composer renders the sounds. This is done to save file size and enable various modulation capabilities within Composer.

  • Solution: To counter this and bind all the elements together, consider using an additional reverb Send channel (as described in the documentation).

6. Issue: Gain of performers is different in Composer compared to Reaper.​

Cause:​

Volume relationships may differ depending on how Composer parses the music.

  • Solution : Check your gain staging in Reaper. Ensure your master level peaks close to 0 dB, keep the master fader at unity (0 dB, with no processing such as a limiter), and adjust individual instrument faders for balance. Proper gain staging is crucial.