Sometimes you’ll find that a vocalist has a hard time monitoring bed tracks through headphones. Here’s a trick to overcome that problem.
Set up the vocal mic and put a pair of Auratones, or similar small monitors, about three feet on either side of the microphone; use a tape measure to ensure that they are equidistant. Next, place the speakers 90 degrees off axis and point them directly at the microphone. Then, feed the monitors from a mono cue mix bus, and reverse the polarity on one of them and cut a bit of top and bottom as well. The vocalist will hear the speakers, due to the distance between his or her ears, but the speaker output will be 180 degrees out of phase at the mic capsule. Therefore, the bed track bleed, though not absolutely gone, will be down by about 30dB.
Be careful not to feed anything to the speakers that you don’t intend to use in the final mix, and don’t run them any louder than necessary for the vocalist to sing in tune and in time. A little bit of bleed won’t kill you. No one ever decided not to buy an album because there was a bit of instrumental bleed in the vocal mic! If you degrade the hi-fi quality by 5 per cent, but improve the performance by 30 per cent, it’s a no-brainer. Always let technology serve the art, not vice-versa.