Sometimes, you want to detune a couple of oscillators (1 and 2 have fine tune control) so you get some nice movement in the sound. Problem is that a fixed amount of detuning will not sound even across the whole keyboard range (some synths have a "skewed" detuning that diminishes as you go up the keys, but the MB doesn't). A detuning that sounds nice and fat in the lowest keys will give a fast beating in the upper register. Now you may want this on certain sounds, but it is generally unpleasant to the ear.
To get a nice, even detune (between oscillators 1 and 2 for instance) across the whole keyboard range, make the fine tune of Osc2 a Mod destination (for example Destination 13).
Then, apply the Kbd/Seq Mod Source to Destination 13 and set a positive amount with the Mod Amount knob. Adjust Osc2 fine tune so Osc 1 and 2 are nicely detuned in the lowest notes, then trim Mod Amount of I13 to the right level so the highest notes are not too detuned. You may have to repeat those last two steps to get it just right. Voilą!
Note 1: this is also valid in Paraphonic mode, specially if you play closed voicing chords. However it may be hard to do when actually in Paraphonic mode. I suggest momentarily switching to Monophonic mode to set the detune, and go back to Para to check it out.
Note2: Of course, for Para Mode, using the Chorus effect is very useful. Detuning + Chorus can sound very big!
