How to use a split-tracks

What is a split-tracks?
To begin, let’s define what a split-track CD really is. Answer—a regular CD that you can play in any CD player, that has the just the vocals on one channel and just the instrumental accompaniment on the other channel. On the side with the vocals, there are no solos, solo speaking, or small groups, so the soloist is free to interpret differently and so it really sounds like a solo in performance (no one else singing along on the track). This is sometimes called “accompaniment CD,” or “split-channel CD.”

OK, so a split-track CD has vocals on one side and music on the other side, now what?
There are two ways to use the split-track CD, for rehearsal and performance. Using the split-track CD for rehearsals The reasons for using the split-track for rehearsals: 1) no piano player or accompanist available, 2) singing with the music only, what you hear on the listening CD, and 3) rehearsing a specific section and finding it easily. 

Why not just sing along with the listening CD?
You certainly can, and a lot of people do it this way. If you have a way to turn the vocal side up or down, however, then you could rehearse with your choir with the recorded vocals loud or soft, depending on how much help you need for your choir. When singing along with the listening CD, usually the vocals are too loud for the choir to blend with the music. The split-track also lets you play just the music to rehearse with.

Using the split-track CD for performance
The advantage of using the split-track for performance is that you have the same music to sing to as what you hear on the listening CD. There’s nothing wrong with using just piano or a small group of instruments, but to sing with what you hear on the listening CD, use the split-track to perform with. To use the split-track, consult with your sound engineer. They should know how to set this up. In short, they’ll need to run a line out of the CD player (a stereo Y-cable, out of the headphone jack, or line-out, to two mono outs). Take the two mono outs from the Y-cable (one is the left channel and the other is the right channel) and plug these into the line-in inputs in the mixing board. (Additional adapters may be needed). Now the sound engineer has two controls for the split-track, one for the music on the CD and one for the vocals on the CD. Use these two channels on the board to mix the level of the accompaniment and add the right amount of recorded vocals to the live vocal choir. This makes smaller groups sound a little bigger and helps with the overall sound. If you have a large or very large choir, then you may not need or want any CD vocals at all.