[maxmsp] (Ambisonics) methods for encoding A-Format to B-Format

Hi Julien,

You don't need FFTs.

A-format is the four signals from the capsules - left-front/back and 
right-front/back. To get B-format:

X = 0.5 ((LF - LB) + (RF - RB))
Y = 0.5 ((LF - RB) - (RF - LB))
Z = 0.5 ((LF - LB) + (RB - RF))
W = 0.5 (LF + LB + RF + RB)

(Rumsey,F., 'Spatial Audio', Focal Press, pp 113-114)

-- 
O


julienbreval wrote:
> Hello,
> 
> I would like to know which techniques exist for encoding the output
> of a A-Format microphone (eg see the Soundfield SPS200 or the Core
> Sound TetraMic) to usual B-Format (WXYZ).