Polyphony Limits

[GrooveNinja]

How do I know when I have run out of voices? For example, I have seven MIDI tracks that are each playing a different patch on a different channel in VirusControl. When soloed, each one plays fine. However, when I try to play all of them at the same time, one of the tracks will not produce any sound. Which track seems random. I can see that the midi is playing, and I can solo that track and get the sound. Have I run out of polyphony already? If so, is there a deterministic way in which I can know when I will not have enough voices to add another track?