Auto Room Eq; Omnidirectional Pick-Up Pattern; Free-Field Pick-Up Pattern - SABINE Power-Q Operating Information Manual

Most typically, either a cardioid, an omnidirectional, or a free-field microphone is used as a reference
microphone. A cardioid mic is directional in nature, that is, it is more sensitive to sound entering the front
of the capsule, in the same plane as the long dimension of the microphone, as shown below:
An omnidirectional microphone is more equally sensitive to frequencies from all directions, also measured
in the plane of the microphone's long dimension, as shown below:
A free-field microphone is a particular kind of omnidirectional microphone, designed to more closely
approximate the ideal free field (i.e., free from reflected sound) condition of a point-specific microphone
suspended in midair. Free-field mics are typically small diaphragm capsules (to minimize coloration from
sound reflections from the mic itself), and are generally pointed upward when used, to pick up sound in the
plane perpendicular to the plane of the length of the microphone, as shown below:
This orientation is more likely to produce accurate frequency response measurement in the same direc-
tional orientation as the ears of the listener, i.e., parallel to the floor and perpendicular to the apparent
direction of the microphone's pointing.
In most circumstances a free-field microphone is the best choice for room analysis. However, in some
instances a cardioid mic may serve better. For example, in a small room, the direct sound field will be
much smaller in comparison to the reverberant field, and a cardioid ref mic aimed away from a close
reflective wall will minimize phase cancellation and coloration from reverberant sound.
The Sabine SQ-1000 is a free-field, exceptionally flat microphone, specially calibrated for use with the
Sabine POWER-Q and REAL-Q2. It is available from authorized Sabine dealers.