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Surround Techniques by Toru Kamekawa

An Explanation of Various Surround Microphone Techniques by Toru Kamekawa
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The original method uses Neumann M50 mics for the L,C.R positions.
Neumann M50 has directivity above 2kHz using spherical globes.

Two omni directional microphones on the outside locations.

The method invented by Mr. Fukada of NHK ( Japan Broadcasting Corporation, Japan) arranges five cardioid microphones for L,C,R,LS,and RS, and two omni directional microphones.

The distances between microphones are set to Critical Distances.

  This is the method that Mr. Fukada used in an AES surround experiment at The Symphony Hall, Osaka, Japan, in September, 2006.

It uses omni directional microphones (DPA4006) for L, C, and R. For LS and RS. 
Increased directivity in the high frequencies is accomplished by using an acoustic pressure equalizer ball (L50).

  This is the method proposed by Polyhymnia International (former Phillips Classical).

Omni directional microphones are arranged according to the loudspeaker arrangement as defined by ITU-R BS775.

  This is the surround version of INA3. The initials mean "Ideal array of cardioid microphones" in Flemish, the Dutch language.

This microphone arrangement is based on the William Curve by M.William.
(L-R angle is 180° as shown in the left arrangement. )

  This method is invented by Mr. G.Theile of IRT, a broadcasting laboratory in Germany. 

The influence of the sound from the opposite side is reduced. Omni directional microphones are used for compensation of the low frequency response (under 100 Hz) when using super-cardioid microphones.
  This is the surround version of OCT. 
The recording angle is changed by adjusting the dimension “b” (Distance between L and R). 

The recording angle is 110° when “b” is 60cm.
The recording angle is 90° when “b” is 80cm.
  This method uses two omni directional microphones for L and R, and a figure-eight microphone for C. 

The omni direction mics provide a rich and extended impression with ample bass response. The C channel figure eight provides stablization.
  This is the surround version of Omni+8. 
In case of significant sound reflections in the room, figure-eight microphones might be used for LS, RS.
  Two cardioid microphones and a figure-eight microphone faced sideway make four channels with the following equations.

L=Mfront+S, R=Mfront-S
Ls=Mrear+S, Rs=Mrear-S
  This is a microphone array for capturing ambience designed by Mr. G.Theile of IRT, a broadcasting laboratory in Germany.

This is the method for capturing ambience designed by Mr. Hamazaki of NHK (Japan Broadcasting Corporation, Japan)).

Four figure-eight microphones are arranged in a square.  Reflected sound from each sidewall minimizes the influence of direct sound from the front.

  Four omni directional microphones are arranged in a square.

This is the method based on the idea of "Ambisonic" designed by Mr. M.A.Garzon. It gets surround sound from three dimensions of the performance space.

A-Format: Four cardioid microphones are arranged at FU(front upper), RU (rear upper), LD(left lower) , and RD (right lower).

B-Format: Three omni directional microphones and three figure eight microphones are arranged in the direction of X(front), Y(side), and Z(height).

  Two figure-eight microphones (CCM68) are arranged on both sides of each of Schopes (KFM360) facing the front.

L=L(KFM) + L(CCM68)
R=R(KFM) + R(CCM68)
LS=L(KFM) - L(CCM68)
RS=R(KFM) - R(CCM68)

Toru Kamekawa profile:

In 1983 he graduated  Sound Design studies at the Kyushu Institute of Design, and entered NHK(Japan Broadcasting Corporation, Japan).

After being engaged in audio program production, he then took charge of the musical programs of the NHK Symphony Orchestra, Tokyo concert etc., involving research of new recording production techniques like 5.1 surround, etc. for high-definition television.

He assumed the position of the associate professor of Department of Musicology at Tokyo University of Arts in October, 2002. He is teaching and researching of the sound and the recording technology as a  professor now.