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18.05.2006 Angelo Farina
© UNIPR (2006) | All Rights Reserved | Confidential
What
about source directivity ?
§Current
3D IR sampling is still based on the usage of an “omnidirectional” source
§The
knowledge of the 3D IR measured in this way provide no information about the soundfield generated inside the room from a directive source
(i.e., a musical instrument, a singer, etc.)
§Dave Malham suggested to represent also the source directivity with a
set of spherical harmonics, called O-format
- this is perfectly reciprocal to the representation
of the microphone directivity with the B-format signals (Soundfield microphone).
§Consequently,
a complete and reciprocal spatial transfer function can be defined, employing a 4-channels O-format source and a 4-channels B-format receiver:
Portable PC with 4in-4out channels
sound board
O-format
4-channels source
B-format 4-channels microphone
(Soundfield)