Conventionally a sound field is characterised by the instantaneous pressure variations in an extended region of space. This paper considers an efficient and general representation of an arbitrary sound field based on a spherical harmonic expansion or modes. It is shown how the Taylor series expansion and the Ambisonics sound field representation can be subsumed into the spherical harmonic expansion description. This clarifies the nature and degree of these common approximations and suggests a more natural and efficient generalization.
This paper costs $33 for non-members and is free for AES members and E-Library subscribers.