

If you do not want to have the built in synthesizer on the keyboard itself make the sound, you do not need to assign the Mio as a MIDI output device. The keyboard will then generate sound just as if you were pressing the keys, and the sound will have to come out of your keyboard itself either by internal speakers or by audio out to an external speaker, or by an audio out from the keyboard to an audio interface set as the input for a Sonar audio track and that audio track must have its output set to an audio interface connected to a speaker. If you want to make your keyboard itself generate sound, you need to send MIDI data (output of a Sonar MIDI track) to the Mio. What are you using for an audio interface and speakers? Why the Mio set as a MIDI output device should crash Sonar is a mystery, what do you mean by "crash?" Make sure you do not have in and out reversed on the Mio to keyboard.

The Mio will not bring audio data "sound" either into or out of the keyboard. The Mio "out" plugged into your keyboard MIDI "in" will send MIDI data from the computer to your keyboard.

The Mio "in" plugged into your keyboard MIDI "out" will bring MIDI data from the keyboard to the computer. Your equipment should be fine unless it is malfunctioning.
