This a library for Pure Data that provides objects for realtime Vector Base
Amplitude Panning. Vector Base Amplitude Panning (VBAP) is a method for
positioning virtual sources to arbitrary directions using a setup of multiple
loudspeakers. In VBAP the number of loudspeakers can be arbitrary, and they
can be positioned in an arbitrary 2-D or 3-D setups. VBAP produces virtual
sources that are as sharp as is possible with current loudspeaker
configuration and amplitude panning methods, since it uses at one time the
minimum number of loudspeakers needed, one, two, or three.
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With 2-D setups VBAP is a reformulation of the existing pair-wise panning
method. Different from other panning algorithms, VBAP can be generalized for
3-D loudspeaker setups as a triplet-wise panning method. A sound signal is
then applied to one, two, or three loudspeakers simultaneously. VBAP has
certain advantages compared to earlier virtual source positioning methods in
arbitrary layouts. Previous methods either used all loudspeakers to produce
virtual sources, which results in some artefacts, or they used loudspeaker
triplets with a non-generalizable 2-D user interface.
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The directional qualities of virtual sources generated with VBAP can be
stated as follows. Directional coordinates used for this purpose are the
angle between a position vector and the median plane (θcc), and the angle
between a projection of a position vector to the median plane and frontal
direction (Φcc). The perceived θcc direction of a virtual source coincides
well with the VBAP panning direction when a loudspeaker set is near the
median plane. When the loudspeaker set is moved towards a side of a listener,
the perceived θcc direction is biased towards the median plane. The perceived
Φcc direction of an amplitude-panned virtual source is individual and cannot
be predicted with any panning law.
