From: Expanded three-channel mid/side coding for three-dimensional multichannel audio systems
C M
C S
C T
M 0
C 1
C 2
C 3
M 1
2 2 Ssinθ(cotθ+sinφ)
2 2 Ssinθ(cotθ-sinφ)
M 2
2 2 Ssinθ(cotθ+cosφ)
2 2 Ssinθ(cotθ-cosφ)
M 3
Ssinθsin(φ+ π 4 )
Ssinθsin(φ- π 4 )
M 4
6 3 Ssinθ(cotθ+sin(φ+ π 4 ))
6 3 Ssinθ( 2 2 sin(φ+ π 4 )-cotθ)