If you're referring to the harmony parts that are generated to accompany a MIDI melody line, then no, it can't do that without some serious rewriting.
It's very much like expecting a BiaB
style to generate a harmony that follows a melody. RealTracks uses pre-recorded phrases of notes - the length of a bar or longer. To create a harmony part, you'd need the resolution of the RealTrack to go down to the note level.
Your best bet is to get a more realistic sound source, such as
Garritan Jazz and Big Band. Unfortunately, all the real cool articulation and human phrasing that comes for free with RealTracks has to be put in using a controller or manually. But since you've got a wind controller and a Ketron SD2, you already know that...
What you're asking for (in essense) is a program which could use a MIDI file as input, and patch together its output similar to RealBand. Instead of using
notes that have been selected to be bland and blend (for a sampler), if the notes were pieced together out of
phrases, they should be able to keep their articulations and sound much better.
There are a number of products on the market that do that.
Synful Orchestra was the first sample library that I know of that developed a commercial product using that idea. It's got a bunch of instrumental phrases, and builds the output line from there, instead of from individual notes. In theory, the result is a much more natural, expressive output. Unfortunately, the target output is orchestral, not jazz or big band.
Similar technology was apparently used in Garritan's (now discontinued) solo cello and violin. People love these products, but they are currently unavailable, apparently because an agreement couldn't be reached with
the folk who developed the technology, who have gone on to develop their own sets of products, including solo trumpet, trombone and saxophones. These would sound awesome through your wind controller - I hope you've got deep pockets!
There's also
The Mojo Horn Section that appears to use a similar technology, but aims to reproduce a horn
section, instead of simply solo instruments. That's probably closer along the lines of what you've got in mind.
All right, I'll drift
way off tangent for a moment. At this point, there aren't any RealTrack string sections or brass sections, and I'm sort of curious about how you'd put one together. To be useful, you'd have to create a string or brass arrangement that works well over a
lot of different songs in a given style. I suspect
that's the real sticking point: you want enough "style" to be usable, but not to much that it can't be transferred to a lot of songs. That's a tall order.
Plus, unless you're using RealBand, you want a style which you don't have to micro-edit. At some point, it's simpler to play it yourself, or get a sample CD. The real strength of BiaB is the ability to plug and play. A single instrument is a lot cheaper to record than a group, so it's more cost effective.
Still, I'd imagine that it would be possible to write a RealTrack along the lines of the Organ RT - a generic pad. Maybe a horn section could be done with 1/3/7 voicings, and generic riffs between held chords? Most of the sample CDs of horn sections that I've seen concentrate of phrases (which RealTrack already does) and section hits (which I haven't seen). That would be a cool addition!
Anyway, I agree that this would be a cool addition. But I'm not sure how it would be added to BiaB without really going outside their core product line.