by Lucas Van Der Mee,
Sr. Design Engineer at Apogee

Here is a technique I’ve used for a long time that I have found to be very useful in a variety of situations. You can apply it to balance a set of monitors, record an x/y of a choir, and even to separate vocals from a track. I’ve used it many times when receiving a mix with a lot of wide panning of instruments or one that seems to be left-heavy or right-heavy and I want to find the proper balance.

In the old days of tape recording, each two track mix would usually be accompanied by test tones so the engineer could line up each channel and would not have to worry about it. The levels of left and right had to be exactly the same.
But very often those tones were never recorded, or they ended up on a different reel, weren’t available or could not be found anywhere. So then what can you do? Here is a simple trick I learned from a very seasoned broadcast engineer who dealt with the problem all the time.

Set the required level for both channels (left and right). Listen for an instrument or voice that clearly is supposed to be in the center (usually the lead vocal). Now pan both left and right channels to the center. Flip the phase on one of the channels and adjust its fader while listening for nulling/maximum reduction of the instrument or voice you picked as the center reference. Flip the phase back on that channel and pan both channels left/right again. You now have the perfect balance again of the original mix.