Large number of tracks on a file not converting to mp3 right.

So, I decided I'd try and write a song for the high school wind ensemble. This is a pretty big step since I'm used to doing just small indie rock band sort of stuff.

I have no problem with writing these sorts of songs, but I have this problem with finale. The song is comprised of several different tracks, more than I normally do. So, I'm having trouble getting it to save to mp3 properly. Whenever I listen to the saved file, the flutes come out sounding like, I think, a trumpet. is there any method to deal with this problem?

Are you using any vsts or are you using the soundfont?

You're probably exceeding the maximum number of available MIDI channels, which is 16.

Unless you eliminate identical instruments which happen to be using different channels, there's not a lot you can do about this. I suppose you could export as WAV with half the ensemble muted, then do the same with the other half, then combine them in an audio editor of some kind, but that may be a tall order depending on your experience.