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

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).

Fons Adriaensen from Parma has developped an interesting encoding software adapted to the Core Sound microphone:
http://www.kokkinizita.net/papers/tetraproc.pdf
During the encoding, at two moments it uses a FFT-based convolution (see the paper for more details). I wonder which impact these FFT operations have on the recorded signal. Usually, the FFT (especially in realtime) involves a time versus frequency trade-off that can blur sharp attacks. Perhaps there are some special techniques for avoiding it, though I have not heard yet about them.

Core Sound themselves and Soundfield have made such encoders for using with their microphones but they don't give any information about it. Moreover, I didn't find any downloadable B-Format recording of a drums solo or a xylophone, which would show the effect that A- to B-Format encoding has on sharp attacks.

Therefore I am looking for links about it (books, scientific papers or web documents).


Regards,
-j