•At UNIPR-Aida
we had 10 years of experience
employing 1st-order
Ambisonics
microphones (Soundfield TM, DPA-4, Tetramic, Brahma)
•At RAI-CRIT,
the Holophone HD was employed
as the stanadard microphone
system for surround recording
•Both systems
were unsatisfactory in terms of spatial resolutiion and stability of the polar patterns with frequency