There are many ways to record with surround sound in mind. One of the more standardised methods is a technique called a Decca Tree, however there are other array setups such as the IRT cross, the Optimised Cardioid Triangle, the Hamasaki Square and Double MS just to name a few.
I will link below some research into these techniques however they all have specific placements and measurements in order to capture audio for a more immersive experience. Using these techniques as a starting point has led me to create a technique specific for the image i was trying to capture and the requirements to capture this are fundamentally the same starting with spot mics on the kit itself. Building from that then the sound stage was created in order to achieve the sound by using a Binaural microphone and then matching this with other microphones and setups to achieve the desired effect.
With the Binaural mic having DPA4011 capsules using another DPA4011 was chosen as the centre mic to have a similar frequency response to the "surrounds". These where placed at ear level relative the the artists seating position in order to achieve an Artists Perspective with the center mic placed at the same hight facing the artist.
This is the primary setup for the Surrounds, the next was the placement of the room mics where the Moscow method was used with the rear of the mic facing the ground in order to keep any out of phase information to a minimum, however having this many microphones in one area there are bound to be some issues. Having a measured and calculated idea is paramount in order to capture the best sound without and concurrent phase issues, (where the old saying measure twice cut once comes into account) so having a key point of focus such as the snare or kick drum will make this much easier. All of the 'Surround' mics where measured from the outer most spot mic for the kick drum where all the 'Spot' mics where relative to the snare. This was partially due to how much quicker high frequencies travel relative to lower ones and also pointing a focus point on to the relative center of the kit as it was the center of the room respectively. Using the fundamentals of the 'Decca Tree' and then elements from the 'Fukada Tree' for placements and measurements where taken into account for the setup which was key to capturing the sound.
Here are some diagrams and measurements of the key microphone techniques used.
Optimized Cardioid Triangle (OCT)
OCT is an array designed for the three front channels only. The system offers high separation between left-center and right-center. An additional configuration for the surround channels should be chosen carefully.
A cardioid microphone is used for the center channel placed only 8 cm (3.1 in) in front of two higher-order directional cardioids for left and right channels, pointing outwards. The spacing between the left and right microphones is the key to the desired recording angle. Distances between 40 cm (15.7 in) and 90 cm (35.4) are recommended from the designers, resulting in recording angles from 160° to 90°.
One or more pressure (omnidirectional) microphones can be added to the system to compensate for the missing low frequency from the pressure gradient capsules of the cardioids.
Fukada Tree
The Fukada Tree is a Decca Tree array, but with five cardioid microphones and two additional omnidirectional microphones as outriggers to blend in between the front and rear channels. This setup was designed by Akira Fukada in 1997.
The choice of cardioid microphones improves the channel separation, and the backward-oriented rear cardioids also minimize leakage of direct frontal sound to the rear speakers.
Omnidirectional microphones are often preferred in Decca Tree configurations for music recordings due to their natural sound color and full frequency bandwidth. The two omni outriggers serve this very important component in the Fukada Tree array.
Gasull Ruiz, Allejandro: A Description of an Object-Based Audio Workflow for Media Productions. Convention Paper 9570, AES 140th Convention, Paris 2016.
Steven A.: Object-based audio for television production. IBC 2015.
Messonnier, Jean-Christophe et al.: Object-based audio recording methods. Conference proceedings, AES 57th International Conference, USA, 2015.
Williams, Michael; Guillaume Le Dû: Multichannel sound recording, Multichannel Microphone Array Design (MMAD). 2010. http://microphone-data.com//media/filestore/articles/MMAD-10.pdf
Williams, Michael: Microphone Arrays for Stereo and Multichannel Sound Recording Vol II. ISBN 978-88-7365-104-8. Milano 2013.
Shirley, Ben et al.: Personalized Object-Based Audio for Hearing Impaired TV Viewers. Journal of the Audio Engineering Society, Vol. 65, No. 4, April 2017.