The Decca Tree is a well-established stereo microphone technique, originally developed by engineers at Decca Records in the 1950s, and widely used to this day in recording orchestras, choirs, and film soundtracks. The setup uses an arrangement of three spaced microphones, usually with an omnidirectional polar pattern, mounted on a tall T-shaped or triangular stand.

In this arrangement, two microphones are placed laterally approximately two meters apart, while a third central microphone is positioned about one meter in front, forming the vertex of the triangle. The resulting stereo image is formed by the combination of differences in sound arrival time and intensity differences between the capsules. The central microphone has the crucial function of stabilizing the sound image, filling the central void that can occur in purely spaced techniques, ensuring a solid and coherent image. Due to the time differences involved between the microphones, the sum of the channels for mono may exhibit timbral coloration or phase cancellations.