Part II: The Definition of Multitracking
(for Part I, click here)
You've been patient, so here it is. Multitrack is a recording technique where you record one thing (like a guitar) then rewind the tape, play it back, and record something else (like singing) onto a different tape while the first one is playing. That's it. Since the tapes are perfectly synchronized using some sort of wacky voodoo magic, you can play them back and it sounds like one recording. You can keep doing this with as many instruments as you want as long as you have enough tape (or hard disk space in our makeshift musician case). The advantage of this is that you can now, most importantly, change the volume level on each track individually without affecting the other tracks, and keep doing it until it sounds perfect. You could also record multiple tracks at the same time, like at a live show. Multitrack was invented by the legendary Les Paul in the 40's. He had a device that could sync up eight different tapes so he could record eight separate parts.
"I still don't get it. What's wrong with just using one microphone and just having the band play? They sound better when they play together anyway, right?" you ask. Man, you're a tough crowd. Even if you want to record all of them at once, you still need different microphones to record each band member. You know, the microphone in front of the singer isn't really going to pick up the drums that are fifteen feet away, is it? But that is an issue for a different blog post.
So here's the process:
Let's say you have a drummer named Judy and a dude who plays guitar and sings named Michael Douglas. Before coming to the studio they've memorized the song that they want recorded. First we record Judy's drumming onto a track. Now we have the drum part for the entire song recorded. Next we rewind back to the beginning of her tape and give Michael Douglas a pair of headphones and stick him with his guitar in front of a mike. Listening to the drum part Judy recorded earlier on his headphones, he plays the entire guitar part as if she really is playing drums along with him, and we record it. When he's done he whines about needing a break because he's an artist and he needs to recharge his chi or something. So now when we rewind and play it back we hear both the drums and guitar, and it sounds like they're playing together, even though they didn't. It's like magic!
After probably an hour Michael Douglas gets back. We put him in front of a mike, again with headphones on, and while using the already recorded drum and guitar part as a reference, he sings his vocal part. Now that we're done (and Michael Douglas is just so tired from a rough day of work) we can get to the fun part, which is mixing. Did the drums end up a little too loud compared to the other parts? Well, if we recorded everything at once on a single track, we would be stuck with them unless we wanted to record everything over again. Since we recorded them on their own track though, we can just turn the volume down on 'em. Then we keep tweaking things like stereo panning, equalization, (yet another topic which I'll get to), and effects like reverberation (kind of like echo), until the song sounds perfect.
Every album you've ever listened to, unless it is very old or explicitly a live performance, is made in this fashion. Listen to your music intelligently and you might be able to pick out each track yourself. Listen to how each song is carefully arranged and mixed and you'll have a much better appreciation for the studio process and musicians in general.