Assuming you are going to make a multi-camera shoot of a playback performance, I would suggest to use a simple photocamera flash to synchronize the different cameras, again assuming you do not have genlock capabilities. What also helps is that the date and time of the various cameras are properly matched prior to the recording. If you then use Scenalyzer to capture, it will automatically add the date and time of the recording to the filenames. This makes it a lot easier to identify shots and lipsynch those.
Even if tedious, you could also synchronize on the waveform, but it is not as accurate as a simple flash. Take all shots with a clear recording of the original sound that is being playbacked. The sound of the musicians is not very relevant and will be removevd anyway.
Harm Millaard