At 70 cm distance it is about equivalent to the pickup angle of the near-coincident ORTF-setup. If you increase the distance between the microphones you effectively decrease the pickup angle. According to Eberhard Sengpiel this is enough to locate the sound source exactly at the speaker on the respective side, resulting in a stereophonic pickup angle of 180°. At a distance of about 50 cm (0.5 m) the time delay for a signal reaching first one and then the other microphone from the side is approximately 1.5 msec (1 to 2 msec). This uses two parallel omnidirectional microphones some distance apart, so capturing time-of-arrival stereo information as well as some level (amplitude) difference information, especially if employed in close proximity to the sound source(s). The sonic image produced by this configuration is considered by many authorities to create a most realistic, almost holographic soundstage.Ī-B technique: time-of-arrival stereophony When the microphones are bidirectional and placed facing +-45° with respect to the sound source the X-Y-setup is called a Blumlein Pair. Due to the lack of differences in time-of-arrival / phase-ambiguities, the sonic characteristic of X-Y recordings is generally less spacy and has less depth compared to recordings employing an AB-setup. A stereo effect is achieved through differences in sound pressure level between two microphones. Here there are two directional microphones at the same place, and typically pointing at an angle 90° or more to each other - see also "The Stereophonic Zoom" by Michael Williams. Various methods of stereo recording X-Y technique: intensity stereophony
0 Comments
Leave a Reply. |