This youtube video shows the same man playing 6 instruments, recorded at different times, but all 6 split-screened versions of him are playing in synch. I’ve seen this once before but that time the guy had headphones on, so I assumed that he was listening to himself so he could play along on the second instrument, etc.
Any ideas how the musician in the following video was able to keep all versions of himself in synch?
Here’s the video: http://youtu.be/bGR3qkG3Dwc
One way would be to use a metronome or a click track to keep the tempo, most pop and rock music is recorded one instrument at a time with either a click track or a basic rhythm track.
It’s also possible that a musician talented enough to play all those instruments is capable of keeping time for a short piece like that.
He might still be wearing headphones and you can’t tell in that video. You can get pretty small ones these days. I’d tend towards a less disappointing explanation, myself, but that’s one possibility. 
I think the second scenario is pretty unlikely. Even the slightest variation would be compounded over time, and I heard nothing like that.
I did not hear a metronome or any kind of audible beat. Maybe he used a visual cue.
If it was a longer piece I’d certainly agree with you, but for such a short piece I think it’s possible. Especially as he could have recorded each part many times, and used the takes that are in perfect time with each other.
I’d say he’s got a speaker in the room that plays back the first instrument he’s recorded - the contrabassoon, for instance. Because it’s in the mix anyway a little bleed to the other recordings isn’t too bad, and you have yourself a neat time reference. No way did he just wing it - even the slightest variation in tempo would make a recording unusable. We’re talking tens of milliseconds here over 100 seconds, it can’t be done.
If you look carefully at the bottom 3 panels, you can see a wire hanging behind him. Could be running a click track, or electronic metronome, into an earpiece.
Here’s another one, but it’s pretty clear how this guy did it. Headphones, heavy, heavy editing and lots of patience, but it’s still fun to watch.
The bassoon player has a small black box on the right side of his music stand (to our perspective). That could be a tuner, a metronome or both. Digital metronomes have an LED which flashes on the beat, and they either have a silent mode or you turn the volume all the way down. Once that bassoon part, with all of its running sixteenth notes, is down, the others would be easier to dub. Or perhaps the metronome is better concealed in the other five shots.
Notice I didn’t say ‘easy’, I just said ‘easier’ - it’s still very cool in any case.
He’s clearly wearing earphones. You can see the wire trailing behind his neck in the saxophone panel.
I’m somewhat into the multitrack scene. Many vocalists record and mix with an audio program, and then come back and lipsync. Well, they actually sing, but they aren’t recording the audio. That would be really easy to do with instruments.
But it doesn’t appear he did that. While I can’t see the wire in the sax panel, I can see it in the contra (top right) and flute panels. Even if that was a wireless mic chord, the presence of such would indicate he isn’t miming his playing.
In the one multitrack I did, I just recorded with a head set mic and had the other tracks come out of the speakers. But this guy is clearly using something to keep tempo. It’s too strict otherwise.
I think the simplest explanation is probably the best.
He doesn’t seem to be wearing headphones, so he must be listening through a speaker. And since he must be monitoring through a speaker, he’s not working to a click track (otherwise you would hear it bleeding into the microphone). He probably just started with the most consistent part, then recorded the other parts playing along with himself. It’s not exactly the cleanest way to record, but for a youtube video of that quality, it will do.
I once recorded a video of myself playing in much the same way: http://www.youtube.com/watch?v=3IqssPdbKpg
Many possible methods:
Headrush is right, any of those are possiblilities. I’d put my money on a click track or off camera speaker.
It’s quite simple to do, really, with practice.
The other really simple option is that he used keyframing to lock the video frames and elastic audio (pro tools) or flex time (logic) or the like.
Paul McCartney & Wings, Coming Up. Paul played all the instruments, and several vocal tracks and Linda did a few vocal tracks.
Then they used special effects for the video and everyone in the band is either Paul or Linda.
I’d guess the little black box previously mentioned is something like this:
Boss DB-60 Dr. Beat Metronome
There is very clearly a drum beat with cymbals playing behind the music. He may be using a metronome or headphone or whatever, but the actual drum beat playing probably helped more than anything
Best example I’ve ever seen of this kind of thing:
And now for something (not) entirely different…
And, of course, there’s this virtuoso…