Is it possible to assign one or more of the sixteen tracks of an MX88 Performance to an external instrument (for example an Ipad app) by putting only those in MIDI local off?

We think we know what you are asking — the MX88 has no “Tracks”, it has 16 “Parts”. The difference is profound.

Tracks in a MIDI system contain a documentation of events that represent a musical performance. So if you are using an external MIDI Sequencer it would be where you have MIDI Tracks.

Each MIDI Track is set to transmit on a specific MIDI Port, on a specific MIDI Channel, 1-16. Each MX88 Part is set to Receive a specific a Track routed to MX88 on Port 1, on a specific Channel, 1-16, that specific MX88 Part will sound.

If you route the MIDI Track on a Port that feeds a different device, then that device will sound.
For example, if you are using the MX88 as your MIDI interface via USB, any sequencer Track routed to MX88-1 (Port1) it will trigger the MX88 tone engine. But if you set the MIDI Track to MX88-3 (Port3) it will trigger whatever external instrument you connect to the 5-pin MIDI OUT on the MX back panel.

Extra Credit:
“LOCAL CONTROL” refers to the Keyboard and its physical Controllers in a MIDI System. Normally, Local Control = On — this allows the MX88 keys, wheels, foot pedals, etc., to address the MX Tone Generator directly (thus the word “local” ).

When working in a MIDI Recording system with a Host (computer/tablet) with a software sequencer, it is typical to set Local Control = Off — this way you can determine all Routing decisions in the Host software on a Track-by-Track basis...

By disconnecting the local connection between the MX88 keys, wheel, pedals etc and the MX88 internal engine, you can have your MX88 play/control whatever sound you desire... the *active* MIDI Track in the sequencing software (the one highlighted) will determine which tone engine responds, be it the MX88 itself or an external instrument connected to the 5-pin OUT or even a plug-in synth via the software.

Hope that helps.

Is it possible to assign one or more of the sixteen tracks of an MX88 Performance to an external instrument (for example an Ipad app) by putting only those in MIDI local off?

I'm going to guess here that your goal is to take advantage of the MX's ability to use the 16 buttons to, not only alter the sound that you're playing, but simultaneously change what MIDI channel you're transmitting on.

While "Local Off" by definition is global to all channels, there are still ways to silence one part of a 16-part multi-timbral tone generator, which is essentially what the MX is even if you're using the buttons to play only one (or two) of the sounds at a time (or possibly more if you've assembled sound combinations with an external editor).

If you use an external editor (Vycro MX, John Melas' tools), you should be able to assign a "silent" voice to Part 16 to make this work, by assigning an existing voice and changing its parameters so that it is inaudible. In fact, I think all you have to do is edit a Performance such that whatever sound is assigned to Part 16 has its volume set to zero. I would not exoect that volume parameter to affect the MIDI Out. So then selecting Part 16 in that Performance will play a "silent" MX Voice, along with whatever iPad sound you have set to respond to MIDI channel 16.

Many thanks, I'll try and keep you informed :). The MX88 has a lot of of possibilities and I'm studying to obtain the maximum.