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Ambisonics
Ambisonics is a ''full-sphere'' surround sound format: in addition to the horizontal plane, it covers sound sources above and below the listener. Unlike some other multichannel surround formats, its transmission channels do not carry speaker signals. Instead, they contain a speaker-independent representation of a sound field called ''B-format'', which is then ''decoded'' to the listener's speaker setup. This extra step allows the producer to think in terms of source directions rather than loudspeaker positions, and offers the listener a considerable degree of flexibility as to the layout and number of speakers used for playback. Ambisonics was developed in the UK in the 1970s under the auspices of the British National Research Development Corporation. Despite its solid technical foundation and many advantages, Ambisonics had not until recently been a commercial success, and survived only in niche applications and among recording enthusiasts. With the widespread availability ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambisonic Data Exchange Formats
Data exchange formats for Ambisonics have undergone radical changes since the early days of four-track magnetic tape. Researchers working on very high-order systems found no straightforward way to extend the traditional formats to suit their needs. Furthermore, there was no widely accepted formulation of spherical harmonics for acoustics, so one was borrowed from chemistry, quantum mechanics, computer graphics, or other fields, each of which had subtly different conventions. This led to an unfortunate proliferation of mutually incompatible ad hoc formats and much head-scratching. This page attempts to document the different existing formats, their rationales and history, for the terminally curious and those unfortunate enough to have to deal with them in detail. Most modern applications use ACN and SN3D, although ''traditional'' first order is still common. Spherical harmonics in Ambisonics A common formulation for spherical harmonics in the context of Ambisonics is Y_\ell^m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |