# VST Instrument Plugins

A VST Instrument (or VSTi) is a VST Plugin that can convert MIDI messages to audio. You can select a VST Instrument by clicking the instrument slot's down arrow. The VST Instrument plugins appear in the list's Plugins section.

A VST plugin will initially appear in both the Effect and Instrument selectors. The first time it is loaded, MultitrackStudio determines whether it's an effect and/or an instrument. From then on, it will appear in the appropriate selector only.

VST instrument windows have a Channel selector (top right). This is not only the channel used for recording, as with the built-in instruments, it is also the channel on which MIDI data is sent to the plugin. Some plugins respond to all MIDI channels in the same way, in which case the channel setting does not matter. Sometimes you can set a plugin to Omni mode to achieve this. Other plugins, especially multitimbral plugins that can produce a different sound per channel, require that the Channel setting be the same as the channel used by the plugin.

VST Instruments respond to all the streams in the track's MIDI file. However, in most cases, it's easier to use multiple tracks (each using an instance of the VST Instrument) instead.

### MIDI 2.0 / MPE

VST3 instruments that support VST3 note expression receive per-note Pitch Bend, Volume, Pan, Expression, Brightness, and Vibrato Depth. Poly Aftertouch is sent as well. VST3 instruments that don't support note expression will receive MPE just like VST2 plugins (see below).

A VST3 plugin that generates MIDI output can use note expression to send per-note controls.

VST2 instruments receive per-note pitch bend, per-note brightness, and poly aftertouch via MPE. Switching to MPE happens automatically when per-note pitch bend or per-note brightness is sent to the plugin. MPE won’t be used if you set the per-note pitch bend range to zero.
Plugins may have an MPE mode setting that must be set manually.

MIDI output from a VST2 plugin is converted from MPE to MIDI 2.0. You can avoid this by setting the per-note pitch bend range to zero. In this case, MPE-to-MIDI 2.0 conversion will only take place if the plugin sends MPE configuration messages (RPN 6).

For VST3, several MIDI-CI profiles are supported.