Unify Manual

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MIDI Filter

Unify's built-in MIDI Filter effect does what its name implies: filters incoming MIDI events, in order to:

  • select only events matching certain criteria,
  • filter out specific events, or
  • modify certain event-sequences.

Input filtering: Channel and Note-range

The Channel and Range section allows you to select only events on a specific MIDI channel, and/or note-events in a specific range. The controls in this section work the same as their counterparts on each MIDI and INST layer in the layer-stack view.

Channel and pitch modification: Modify

The Modify section contains two more controls which also have direct counterparts on each MIDI and INST layer in the layer-stack view.

  • Transpose specifies the number of semitones by which incoming note-events should be transposed
  • MIDI Channel allows you to specify the MIDI channel on which incoming events are output, regardless of the channel they came in on.

Sustain Pedal functions

There are four options for Sustain Pedal (CC#64) events:

  1. Pass Thru: allow CC#64 events to pass through unaffected
  2. Suppress: filter CC#64 events out of the MIDI stream entirely
  3. Emulate: suppress CC#64 events, but interpret them so note-off events are delayed until pedal-up
  4. Em + Latch: like Emulate, but sustain pedal toggles note latching on/off

The first two options are self-explanatory, but Emulate and Em + Latch require a bit of explanation.

Emulate mode is useful for plug-ins which either ignore MIDI CC#64 events entirely, or don't handle them properly. (Unfortunately, there are quite a few plug-ins like this, including the BlueARP arpeggiator, and literally hundreds of free VSTi's) In Emulate mode, MIDI note-off events are suppressed while the Sustain pedal is down, and sent all at once when the pedal is released. Hence notes are held (sustained) while the pedal is down, just as you would expect if the downstream plug-in was interpreting CC#64 itself.

Em + Latch (emulate with latch) mode is basically the same as Emulate mode, except that you don't have to hold the sustain pedal down. Instead, you press and release the pedal once to activate sustain (the letters “SUS” will appear in green text next to the menu), and a second time to de-activate it.

Suppressing events

The Suppress (filter OUT) section is mainly about removing selected events from the MIDI data stream, but the Repeated checkbox is an exception; it actually inserts events when required.

All Notes

Checking the All notes box causes MIDI Filter to suppress all MIDI note-on and note-off events. This can be useful when you want to pass only e.g. CC events to the next plug-in in the chain.


Most MIDI keyboards will transmit a MIDI note-on event when a key is pressed down, and a corresponding note-off event when the key is released. A few keyboards (in particular Casio's Privia digital pianos) do not send note-off events during legato runs, and this can confuse some software instrument plug-ins (in particular KORG's TRITON).

Checking the Repeated box will cause MIDI Filter detect when note-off events are missing, and re-insert them into the output stream (immediately before the next note-on).

Pitch Bend and AfterTouch filtering

When working with multiple instrument layers, you may occasionally want to ensure that only some layers respond to Pitch Bend or Channel Pressure (aka aftertouch events).

  • Check the Suppress PB box to filter Pitch Bend events out of the MIDI stream.
  • Check the AfterTouch box to filter out both Channel Pressure (mono aftertouch) and Aftertouch (i.e., polyphonic aftertouch) events.

To filter out mod-wheel events, see below under CC filtering.

System Common, System Exclusive, and Real-Time filtering

A few MIDI controllers transmit MIDI System Common, System Exclusive (aka SysEx), and Real-Time messages, and there are rare cases of plug-ins which may get confused by these.

  • Check the SysComm/SysEx/RealTime box to filter all such events out of the MIDI stream.

Mod Wheel and other Continuous Controller (CC) filtering

An earlier version of MIDI Filter featured a checkbox to filter out Mod Wheel (CC#1) events. This has been expanded to a set of six buttons as follows:

  • By default, each button is labeled cc?, indicating “no filtering”
  • Click any button to open a menu of MIDI CC numbers and their associated standard names
  • Select any CC item on the menu to filter out that specific CC
  • Note CC#1 is mod wheel; this is the one you will most often want to suppress
  • Select NONE (the first menu item) to revert the button back to cc? (inactive)
midi-filter.txt · Last modified: 2023/05/08 18:59 by