Stereo microphony techniques
Introduction
The stereo microphony techniques began their development when the recording went from mono to stereo, and that were accustomed to creating a sound image that would replicate the particular live sound. Humans have two ears, which suggests that the sound comes to interval with a difference of milliseconds, that the brain can determine the path within which the sound originated. Stereo microphony techniques give recordings sensation of directionality.
Developing
Theory of the techniques chosen.
Coincidental (AB).
Microphones used: two directional microphones, usually of small diaphragm condenser. Its placement form must be at an angle between 90-135 degrees so that the capsules coincide only by an area. The more clear the angle, the wider the stereo image will be.
Separate torque (xy)
The separate torque technique consists of two individual microphones, typically using cardioid or omnidirectional polar patterns, spaced to each to capture a large stereo image of an instrument or set or set.Its placement is that both microphones must be oriented towards the instrument at a distance of about 30 cm from it and maintaining a separation of about 60 cm between one microphone and therefore the other.
Semicoincident Par (ORTF)
Called by the French television station that invented it, the ORTF is a stereo technique designed to imitate the placement of human ears. To do this, you have to place two identical cardioid microphones separate exactly 17 cm, one in front of the other at an angle of 110 degrees. The resulting audio must be very close to the width and directionality that is experienced when listening to any sound source (stereo microphone techniques, n.d.). With this technique you would have to collect less ambient sound.
MID SIDE (MS)
The MID-IDE technique (also known as M-S) is the most involved stereo technique but gives you extra control over the results. To perform this method you will need a cardioid microphone, and also a bidirectional microphone. The cardioid microphone looks towards the sound fount. The track recorded with the SIDE information must then be duplicated, and also the phase must be invested in the duplicate track, with the initial panoramic view strongly on the left, and also the overview of the right. The cardioid channel is usually panoraminized in the center. By adjusting the amount of average channels in front of the side channels, the stereo image is often altered to transmit different results.
Blumlein.
The Blumlein technique is incredibly similar to A/B except that instead of cardioid microphones, bidirectional microphones are used and 90 degrees are also positioned from each other. This means that the microphone that captures the audio to the sound source also captures the right back of the area. Similarly, the microphone that looks forward and right, also captures the back and left. The resulting audio contains both a stereo image of the sound source, with an added environment captured from the rear of the recording space. This could add size and depth to the recording, but a pleasant sound room is crucial for the results.
Decca Tree.
The traditional TREE deccaus configuration uses three M50 Neumann microphones arranged in a triangle of 10 to 12 feet above the director’s position, although the space varies according to the place and size of the set.The left microphone is panoramiza to the left, the right to the right and the central to the center with additional microphones. The distance between the microphones depends on the size of the set. For the orchestra, the left and right microphones are at a distance from 8 to 10 feet, with the center about 6 to 7 feet before the left-right axis.
Conclusions
The positioning of all techniques represents different challenges in relation to the others, so it is essential selected technique/s, as well as always remain attentive to possess the phase microphones.
Bibliography
- Owsinski, b. (n.d.). The Recording Engineer’s Handbook.
- Stereo microphone techniques. (n.d.). Retrieved May 9, 2020.
- Stereo-Audio-Technica Iberia Microphone Techniques. (n.d.). Retrieved May 9, 2020.
- Techniques to record in stereo. (n.d.). Retrieved May 9, 2020.
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