Developer Geert Bevin – the author of the original MPE specification – announced via Facebook that “After 2 years of weekly meetings with the MPE working group, many discussions, heated debates, over 60 revisions, the MIDI 2.0 Profile for MPE is finally available for download from the new MIDI Association website.”
The MIDI-CI Profile for MIDI Polyphonic Expression (MPE) specification makes it possible for artists to perform independent gestures for each musical note, with up to three dimensions of expression. With MPE, every note a musician plays can be articulated individually for much greater expressiveness. MPE already has broad support from many DAWs, synthesizers and controllers.
The specification describes a recommended way of using individual MIDI Channels in MIDI 1.0 and/or MIDI 2.0 to achieve per-note control, enabling richer communication between increasingly expressive MIDI hardware and software.
Here’s a video intro to MPE Profile from The MIDI Association:
You can register and login to download it at The MIDI Association site.
MPE is a clever workaround for MIDI 1.0’s lack of per-note controls (polyphonic aftertouch is the only one in old MIDI).
With MIDI v1, devices can have single or multiple MIDI ports. Each port can have 16 channels of MIDI which can correspond to up to 16 devices (daisy-chained using thru), or up to 16 multi-timbral sounds within one device. MPE sacrifices the original intent of channels and uses it for up to 16 polyphonic voices of per note expression.
The loss of the multi-device or multi-timbral operation is fine for when the focus is on a particular type of controller linked to one particular destination (i.e., track, or device, or instrument).
The development of MPE was pragmatic given the glacial pace of MIDI 2.0 implementation. Credit is due for those companies that got on the MPE wagon quickly. I expect MIDI 2.0 will continue at a snail’s pace for the foreseeable future, so these baby-step transitions seem pretty practical.