Figure of Eight, or Bidirectional, refers to a specific polar pattern where a microphone or loudspeaker exhibits equal sensitivity to signals arriving from directly in front and directly behind the diaphragm, while effectively cancelling out sound arriving from the sides (the null points). Acoustically, this occurs in pressure-gradient transducers where the diaphragm is completely open to sound waves on both sides. A crucial technical detail often overlooked is that the sound captured from the rear is typically 180 degrees out of polarity relative to the sound captured from the front. This characteristic makes the Figure of Eight pattern uniquely powerful for rejection tasks in complex setups and is the foundational component for the Mid-Side stereo recording technique, where it captures the stereo width information.