Advanced Techniques
Automatic Looping and Track Muting
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This feature allows you to automate muting and unmuting of tracks in a looping file to create musical "playlists," which can be of great benefit for reducing the size of a long file. This is accomplished with controllers in the MIDI data which tell the synth to play or not play specific tracks in a predetermined order. It is not a real-time interactive feature.
Here's how it works:
  1. Start with a MIDI sequence designed to loop end-to-end, which does not contain "loopstart" and "loopend" markers.
  2. Insert, in any track, a continuous controller #85 whose value will indicate the total number of loops of the file that will comprise the "playlist" (counting from zero).
  3. Determine which loop repeats in which you want each track to play, and insert controllers as follows: to play track during loop (x): controller 87: (x); to mute track during loop (x): controller 86: (x).
As an example, let's say that you have a file that I want to loop 3 times, and you want to hear a piano solo during the second loop.
On any track, you would insert controller 85: 2, for 3 loops.
Then, on the track with the piano solo, I would insert:
  • On any track, you would insert controller 85: 2, for 3 loops.
  • Then, on the track with the piano solo, you would insert: controller 86=0, controller 87=1, and controller 86=2
A few important points:
  • All of the controller data must be at 1,0,0if a track does not have controller 86/87 data, it will play normally.
  • If there is no controller 86/87 corresponding to a particular loop value, the track in question will remain in its current state, either muted or unmuted.
  • The file will play indefinitely; when the maximum loop value set with controller 85 is reached, it resets to 0.
  • The total number of tracks is limited to 64.
What results from this process is a file of a rather short duration (8 or 16 bars, perhaps) with all of the different sections of the song lined up vertically. The process can be quite laborious and requires great care; because it is based on tracks, not channels, the muting / unmuting feature cannot be auditioned while linked to sequencer. One has to plot out the structure, collapse all the parts into a short sequence (which means this won't work with music that has uneven phrase lengths or meter changes), insert all the controller data, then hear the results after importing the MIDI file into the Editor.
Why would anyone want to go through all this trouble when they could just as easily create a long MIDI sequence with whatever arrangement they pleased? The main benefit of using this feature is decreased file size, typically cutting the MIDI data at least in half, or much more if there is a lot of repetitive pitch bend or continuous controller data. Plus, an RMF file could go on for 5, 10, 20 minutes without repeating itself and still not be appreciably larger than a much shorter version.

Advanced Techniques  / Automatic Looping and Track Muting    top previous page next page