Mark,
I think you've confused a lot of people, and possibly even yourself. You're NOT looking for a MIDI Interface, you're looking for a MIDI Sound Generator. HUGE Difference.
By the way, don't get rid of the Fast Track, you'll be able to use that once you get your sound generator!

There are two kinds of Sound Generators, hardware and software. Let's discuss each, starting with software.

Starting with Band In A Box 2014, it is now possible to assign software synthesizers to each track or part in Band In A Box, AND they can be different synths. In fact, if you were to purchase the Garritan Personal Orchestra, or the Garritan Jazz Band, you would be able to assign different instruments to each instrument part. So, you might assign a wooden Acoustic Bass from the Jazz Band to the Bass Part, and a Steinway piano from the Personal Orchestra to the piano part, and strings from the Personal Orchestra to the strings part, or, maybe a brass section from the Jazz Band, if it's a 'Big Band' swing song.
There are hundreds, if not thousands of libraries that can be used with VSTi players, like the Native Instruments Kontact player. Take the same BIAB file, and play it using something like the Coyote Forte DXi synth, and then again, loaded with the Garritan instruments, and it'll be like your trumpet versus a kazoo. The difference will startle you.
But, there is a drawback. You pay for quality sounds, and you may pay a lot. For Personal Orchestra 4 and Jazz and Big Band 3, you're looking at $300. Then, you have to load the synths and the patches each time you want to play a song. I love my Garritan products, and I can't wait to play with them with my new version of BIAB, but it's kind of a struggle sometimes to get everything set up.

Now, hardware is MUCH easier. Simply plug the MIDI or USB cable into the computer or MIDI interface, which your Fast Track Ultra already has, turn it on, and go. But, you're stuck with ONLY the sounds that come in that particular sound generator. Some inexpensive ones only have just General MIDI and General MIDI 2 sound sets, some of them may have 1,000 sounds.

PG Music sells the Roland SD50 Sound Canvas, which has over 1,100 sounds. http://www.pgmusic.com/rolandsd50.win.htm You'll probably find the sound that will work for you in that.

That SD-50 would work very nicely in your setup, and you could use your MIDI Controller keyboard to play it, but personally, I would be looking at a keyboard that has the sounds built into . Furthermore, because of my lack of playing skills, I like 'arranger keyboards' and some of the latest ones have some pretty awesome features, as well as truly professional level sounds.

My last keyboard was a Korg PA80. It's a great keyboard with good sounds.

This is "On Green Dolphin Steet" using Band In A Box's JDolfin style and the soloist feature. ALL sounds are from the PA80.

If you don't mind spending a few more dollars, look at the Korg PA600, which is the baby brother to my PA800.

Yamaha also makes excellent Arranger Style keyboards.
http://www.ebay.com/itm/YAMAHA-PSRS650-ARRANGER-KEYBOARD-WORKSTATION-NEVER-USED-MINT-/221442366848?pt=Keyboards_MIDI&hash=item338efe5d80

Anyway, what you're looking for is a Sound Generator. Whether you go with a box like the SD-50, or a new or used Yamaha or Korg keyboard, you'll have great sounds without the hassles of having to load them every time you want to play a song, and with an arranger keyboard, you can just sit down and play without ever turning you computer or studio on.

Gary

Last edited by Gary Curran; 05/18/14 10:07 PM.
I'm blessed watching God do what He does best. I've had a few rough years, and I'm still not back to where I want to be, but I'm on the way and things are looking far better now than what they were!