A near-coincident stereo microphone array described in detail by British audio engineer Michael Gerzon (1945 – 1996) but also credited to Tony Faulkner. It comprises a pair of cardioid microphones with capsules spaced 5cm apart at a mutual angle of 120°. The resulting SRA is 130 degrees. This technique captures both time and level differences between channels, and is comparable to similar techniques such as ORTF, RAI, DIN, NOS and others, but with a noticeably smaller spacing and wider mutual angle. It is often used with a shuffling process to enhance the sense of spaciousness at low frequencies.

A set of pioneering technologies developed by the Walt Disney Studios in the late 1930s for the film Fantasia. It was the first commercial surround sound system, which pioneered the use of pan-pots for sound positioning, multitrack recording, overdubbing, click tracks for synchronisation, control tracks for automatic gain control, and more.

An eponymously named near-spaced stereo microphone system developed by Eberhard SengPiel. It comprises a pair of cardioid microphones with capsules spaced 25cm apart at a mutual angle of 90°. The resulting SRA is 90 degrees. This technique captures both time and level differences between channels, and is comparable to similar techniques such as ORTF, RAI, DIN, NOS and others.

Identical audio content carried in both the left and right channels of a stereo system (ie. panned centre), resulting in a phantom centre sound image.

Dr Harvey Fletcher (1884 – 1981) was an American physicist working for Bell Laboratories on the development of  Stereophonic Sound, amongst other things, in the early 1930s. He was a contemporary of Alan Blumlein but was developing stereo techniques entirely independently.

See Double Mid-Sides Array

An extension of the Mid-Sides microphone concept in which a second Mid microphone is added to the array, but facing directly backwards. This system requires only three audio channels, but can be decoded to create five channels as the shared Sides mic is used with the rearward Mid mic to generate rear left and rear right signals suitable for surround sound applications. Sometimes referred to as the DMS format and employed where a compact surround-sound mic array is required.

An acronym for a German standards organisation founded in 1917: Deutsches Institut für Normung. Amongst many audio standards created by this organisation, the DIN stereo microphone array comprises a pair of near-spaced cardioid microphones with capsules spaced 20cm apart at a mutual angle of 90°. The resulting SRA is 101 degrees. This technique captures both time and level differences between channels, and is comparable to similar techniques such as ORTF, RAI, EBS, NOS, and others.

An approach to capturing and reproducing stereophonic sound developed by Dr Harvey Fletcher (of Bell Labs in America) in the early 1930s. A multiplicity of microphones arrayed in front of a large ensemble sample the audio wavefront at different points in space. Each microphone is connected to a corresponding loudspeaker in front of the audience to recreate the same wavefronts. Although effective, this technique was deemed highly impractical at the time, and it evolved through simplification into various spaced-omni microphone techniques.

A technology often employed in headphone monitoring to recreate the acoustic crosstalk between ears which naturally occurs with loudspeaker listening, but which is normally excluded by headphones. A portion of the signal from each channel is fed into the opposite channel with equalisation and a short delay.