Stereo recording techniques

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The recording system of delay time stereophony is called an AB-system. Two microphones are set up side by side (microphone basis) at a certain distance from the sound source. (Fig. 33)

Fig. 33

Due to the distance difference l, resulting between a point P of the sound source and the two microphones A and B, delay time and phase differences occur between the microphone signals, or. between the loudspeaker signals at replay, due to which the stereophonic effect becomes possible. Delay time differences are always combined with more or less strong intensity differences. A and B are mono microphones with unidirectional bidirectional or omnidirectional characteristics; both microphones must have the same characteristic. They immediately reproduce the signals of the left and right channels, L and R. The superimposing of L and R to a mono signal can lead to sound distorting obliteration, which means that there is no fundamental guarantee of compatibility in the AB-system. Further disadvantages are poor directional resolution, the displacement of remote lateral sound sources toward the middle and the risk of a so-called "hole" in the middle. On the other hand it's easier to realize big reproduction width and an impressive room illusion of the recording.

Stereo Recording Techniques (570 KB) Download this document in Acrobat format for printing and offline viewing.

Stereo recording techniques