# Coincident crossed pair

The coincident crossed pair technique traditionally uses two figure-of-eight
microphones angled at 90 degrees pointing to the left and right of the sound
stage (and, due to the rear pickup of the figure-of-eight mic, to the left and
right of the area where the audience would be also). More practically, two cardioid
microphones can be used. They would be angled at 120 degrees were it not for
the drop off in high frequency response at this angle in most mics. A 110-degree
angle of separation is a reasonable compromise. This system was originally proposed
in the 1930s and mathematically inclined audio engineers will claim that this
gives perfect reproduction of the original sound field from a standard pair
of stereo loudspeakers. However perfect the mathematics look on paper, the results
do not bear out the theory. The sound can be good, and you can with effort tell
where the instruments are supposed to be in the sound image. The problem is
that you just don’t feel like you are in the concert hall, or wherever
the recording was made. The fact that human beings do not have coincident ears
might have something to do with it. Separating the mics by around 10 cm tears
the theory into shreds, but it sounds a whole lot better. The ORTF system, named
for the Office de Radiodiffusion Television Francaise, uses two cardioid microphones
spaced at 17 cm angled outwards at 110 degrees, and is simply an extended near-coincident
crossed pair.

The redeeming feature of the coincident crossed pair is that you can mix the
left and right signals into mono and it still sounds fine. Mono, but fine. We
call this mono compatibility and it is important in many situations – the
majority of radio and television listeners still only have one speaker. The
further apart the microphones are spaced, the worse the mono compatibility,
although near-coincident and ORTF systems are still usable.

## The Mix

Mixing is a complicated “mix” of art and science. In this Singing Canary tutorial, follow top engineer Clint Murphy as he takes you on a 60-video, step by step mixing journey.