It is the 21st century and our digital audio workstations allow us pretty much as many tracks as we like. I can't remember the last time I ran out of tracks in my DAW. But if I cast my mind back to an earlier era of recording, running out of tracks was an everyday occurrence. So how did old-style engineers get more tracks out of a 24-track recorder?
Oh, and it's worth saying that having a 24-track recorder was the 'gold standard'. They were mightily expensive at $50,000 or more. Many of us had to work on a budget 16-track machine. My early days in pro recording were on 8-track, and at home I used a 4-track cassette multitrack recorder. So getting those extra tracks was of vital importance.
One basic technique that was commonly used was 'bouncing'. These days, we use the term to mean mixing to a stereo file. But in the days of multitrack tape, it meant mixing several tracks together onto a single track (or two tracks for stereo) on the same tape.
Suppose therefore you were overdubbing and had already filled 22 tracks of your 24-track tape, and had quite a number of overdubs still to do. You could take a group of similar tracks that were easy to mix, such as the background vocals perhaps, and bounce them in stereo to the two remaining tracks. So if you had recorded six tracks of background vocals, you could bounce them to two, and free up four tracks.
Of course, once tracks were bounced in this way, they couldn't later be rebalanced. So you wouldn't choose dissimilar instruments to bounce unless you really had to.
But another useful technique that did not have this limitation was track sharing. Suppose for instance that you had filled up all of your twenty-four tracks yet still wanted to add some extra color to your recording?
Well just because you have used all twenty-four tracks doesn't mean that the tape is full. Not all of the instruments will be playing all of the time. Chances are there are huge gaps where certain instruments or voices are silent. Those gaps can be used to add extra instruments.
It might happen therefore that you have a 24-track recording with all tracks used, but the electric guitar solo only fills around twenty seconds or so of one track (clearly the producer was very persuasive in keeping it so short!). The rest of that track can be used to add, say, a saxophone.
So as the song plays from the beginning, Track 8 (say) starts with saxophone, then after the second chorus suddenly switches over to the electric guitar solo, then goes back to the sax. Hey – you have just turned a 24-track recorder into a 25-track!
But there is a problem. When mixing the song, the fader level and other settings that suit the electric guitar will probably not suit the sax. If it's just the fader, then this can easily be adjusted manually. If it's the EQ too, then there might be more of a problem, particularly if the change has to be done quickly.
(It might be worth saying that in the days of tape, mixing was done by playing the 24-track tape and simultaneously recording onto a stereo machine. There might be a lot of younger DAW users who would have no reason to know that.)
The solution here is to parallel that track onto two channels of the console, so the same track comes up on those two channels. Each instrument can be given its own optimum settings. Switching between the sax and the guitar is a simple matter of muting one channel and unmuting the other, then vice versa.
By now, you probably want to know whether you can do this with your DAW. Well yes you can, but you would have to be crazy, unless you had really maxed out the track capacity of your DAW and still wanted more.
If you want to hear track sharing in action, you could do no better than to explore the work of Roy Wood, of The Move and later The Electric Light Orchestra. He is well known for wanting to cram his recordings with as many instruments as possible, and track sharing was a technique that he commonly used.