I have used Music Creator 5 for several years now mainly as a composition tool but am about to start using it in a live situation, running on a laptop to provide backing for myself and my guitar-playing buddy. A typical song will have 4 or 5 MIDI tracks for drums, a MIDI track for the bass line, and one or two MIDI tracks for synths, all outputting to Cakewalk and 3rd party VSTs. There will also be one or two VSTs in the synth rack for playing real time using a MIDI controller. Using an external usb stereo soundcard, I pan the drums hard left and everything else to the right channel, which in turn goes to a mixer to be mixed with my Juno keyboard en route to the PA.
The system seems to be working well in rehearsal but I have begun to wonder if we may need more flexibilty with the sound for when we encounter venues with challenging acoustics. With this in mind, would it be possible to output MC5 to four channels if I get a four output USB soundcard, such as a Novation Nio 2/4? If this was compatible, and I had the option to output to four different channels, I could send the drums to one, the bass to another, and split any remaining synths across the the other two channels.

No. MC being the beginner/low cost DAW, it's limited to 2 in and 2 out.
An upgrade to SONAR X 3 is very affordable for registered users. 

I do already have Sonar LE installed (I think X1) which was bundled with my Roland A500 pro controller but haven't really used it as MC5 has done everything I've needed. Would this version of Sonar allow me to assign 4 outputs?

I think so, and a reminder that the X-series won't work on XP; Win 7 or 8 only.

Greg & I both happen to use the same sound card/ interface... the Focusrite Saffire.
 
It has 2 inputs which is the limit for the MC series DAWs, and it happens to have 8 outputs. All outputs are assignable. As it turns out, I am actually using all 8 outputs in the Saffire. I have them set up as 4 stereo pairs. Through the years I have used them for various purposes. I'd have to look back there to check and trace the wires to see what my current config is..... but I think
Pair 1 (1&2) to the studio monitors
Pair 2 (3&4) to my headphone amp
Pair 3 (5&6) to the stereo system
Pair 4 (7&8) using just one to send signal to the sub.
 
So essentially, if you have the outputs, you can use them all. I believe the Saffire was designed to do 7+1 surround for movies and games and such things. Most users probably do 2_1 as I do.....simple stereo.
 
I don't know, because I have never experimented with this, so I'm not sure if Music Creator 4,5 or 6 can do the routing for quad or higher. But, in a live band situation, my guess is that generally speaking, you should almost always be using MONO anyway from your speaker system.
 
Venue's with challenging acoustics..... which one isn't?  Yeah I know some are really sweet but in my experience, concrete walls and floors tend to abound. In cases like that, turn down. Low volume is your friend.
 
But yes, you should be able to use MC with an interface that gives you multiple outputs without issues.
 
If you want to get fancy, you can have MC5 send the midi data out to external sound modules and let them play into the PA or a stage amp. I saw a band that was using early DOS Cakewalk to sequence a number of modules in that very manner. Each module had a channel and they all outputted to stage amps or into the mixing console.
 
Such a rig is a disaster waiting to happen. I believe in going the most fool proof way when I need to play out somewhere. In my case, that is a CD or a wave file played on a laptop into the PA as opposed to a complicated rig running a live version of cake with the imbedded VST softsynths and other things..... I call that "tempting the fates"..... but if it works for you and you're having fun with it.... by all means... don't let me dissuade you.
 
that's my 2 cents.

but as Greg said, you can't do that with MC. You can do it with sonar, but not MC. MC is 2 in, 2 out only.

Thanks guys.
 
I think I may just experiment with Sonar and a 4 output soundcard whilst I continue to use MC5 and the 2 output card as I am doing at the moment, which does work pretty well.
 
I take on board the risks of using Cakewalk in a live situation, and it is intended to have a Plan B just in case we hit any real problems, but I have been thinking about how I could minimise the risk. Is it better/safer to have MIDI tracks outputting to a VST synth or, where possible, mix the track down to a wav file and have this play instead?

Basically, yes... MC gives you 2 in and 2 out... or in other words...stereo in and out.
 
HOWEVER.... the interface which has more than 2 outputs will be able to use those 2 outputs from MC and make them available on ALL of it's outputs as the stereo pair.
 
I was doing this from day one on my 8 output Saffire when I was starting out with MC4.
 
In order to use it as an 8 output interface..... with each output being unique.... yes, that would require a DAW capable of providing that sort of output.
 
None of this is needed if you're using it live as I mentioned above..... mono would be the better way to run it in a club. One output is all that's needed to make that happen. Our band had a stereo board but we never used it in stereo. Always mono.

If I were using sonar in a live situation, and my MIDI were static (in other words, I'm not playing a keyboard running MIDI into sonar into a softsynth for output), then I would probably bounce it to an audio track.
 
since you have both static MIDI and live MIDI, I'd bounce the static one so that there are less likely chances of it crashing, then you'll still need the softsynth for the one you're playing live.

Taking on board the advice here I have been tweaking my MC projects and bouncing MIDI tracks to audio tracks where possible, leaving just the soft synths and any assigned MIDI tracks which will be played live. It does seem to be the way forward and the projects appear a lot more compact now in terms of tracks and soft synths in use, but I have discovered one slight negative in that on some projects now, when I hit play, there is a very slight delay on starting. On most songs it won't matter, but where we have a song commencing with a separate intro and I bring MC into play at a certain point, timing is obviously critical and I need that instant reaction that I get when the project is made up largely of MIDI files. 
At present I think I've found a workaround by keeping a short MIDI track assigned to a soft synth to play one or two bars at the start before the audio files kick in, and this seems to give me the instant start again, but I am continuing to experiment with it.