Note Overlap
This property specifies how to handle overlapping instances of the same note on the same MIDI channel. If overlapping instances are allowed, the output device may release the later note prematurely, or the overlapped portion may exhibit acoustic artifacts such as flanging. To prevent overlapping instances, set this property to "Prevent". Preventing note overlaps is strongly recommended if position modulation or offset modulation are used.
For example, suppose two overlapping instances of the same note on the same channel occur as follows:
| Time | Event |
|---|
| 1:000 | first note on |
| 2:000 | second note on |
| 3:000 | first note off |
| 4:000 | second note off |
In this case, the note will likely be cut off at 3:000, in other words the second instance is aborted by the first instance's note off command. Preventing note overlaps results in the following output:
| Time | Event |
|---|
| 1:000 | first note on |
| 2:000 | first note off, second note on |
| 4:000 | second note off |
Instead of the default method shown above, you also have the option to merge the overlapping instances into a single note. In this case the result would be as follows:
| Time | Event |
|---|
| 1:000 | first note on |
| 4:000 | first note off |
The merge option is selectable on a per-channel basis, using the Overlaps column in the Channels bar. The following diagram shows different types of note overlap and possible solutions.
| Partial Overlap |
| 1 | |
| | 2 |
| 00000 | 00000 | 00000 |
| Full Overlap |
| 1 |
| | 2 | |
| 00000 | 00000 | 00000 |
| Uncorrected |
| 1 | 2 | |
| 00000 | 00000 | 00000 |
| Note Overlap Methods |
|---|
| Split | Preserves the overlapping notes. Note messages are added or removed as necessary to ensure that the overlapping notes don't cut each other off. |
|---|
| Merge | Eliminates all but the first note. The overlapping notes are merged into a single note that spans all of them, and gets its velocity from the first note. |
|---|
Selecting a note overlap method is only meaningful if overlap correction is enabled, by setting the Note Overlap master property to Prevent. If Note Overlap is set to Allow, overlap correction is disabled and Split versus Merge is irrelevant. The Note Overlap master property enables overlap correction as a whole, whereas the Overlaps column in the Channels bar determines which correction method (Split or Merge) is used for each channel. The correction method can also be controlled by an internal track, or remotely via MIDI mapping.
Merge has uses beyond overlap correction. It can also be used to concatenate adjacent instances of the same note, so that they become one long note. To do this, you must force the adjacent notes to overlap, typically by slightly increasing their durations, using the track duration property or via duration modulation.